Installation Manual
Contents
1. Thermostat Aquastat connections 24v Low Vol tage Wiring Field 6 I e Ua A e R Hot supply Wiring VOJ R O Reversing Valve Cooling O Y Compressor O Y ON T ell Hot Water Circulator Pump vy Special Instructions E Circ Pumf vee ee ane r ne Relay i Note If heat pump is to be operated without the hot water e e circulator connected to the water a ts tank and flooded with water S remove the wire marked with S RED tape located here 2 g S This pump is water lubricated T A and must not be run dry 380 120v transformer NOTE The domestic hot water circulator pump voltage is Field 120v 1 50 Wiring L3 Hl 2 380v 3Ph 50hz Connections L 1 7 S Compressor relay Connect L3 to Phase 1 Gnd Connect L2 to Phase 2 Compressor relay Connect L1 to Phase 3 E Gnd lug Connect Gnd to gnd lug IMPORTANT NOTE FOR 3 PHASE SCROLL COMPRESSORS This2. Tee Important Instructions 1 Diagram above shows the proper manner of plumbing a tank that has only 2 ports 2 The tank must have at least 1 1 4 fittings at A to accomodate the flow from the heat pump and the floor circ pump when both are in operation 3 The water line between A on the tank and the tee at B should be at least 1 1 4 4 Install a check valve at C and D to prevent backflow through the floor system or the heat pump when only one of the two pumps is running 5 Tank should have an additional 3 4 fitting at M to allow for an imersion well style probe thermostat Page 17 12 Feb 00 Maritime Geothermal Ltd Five x 60 000 Btu DX to Water heat pumps stacked and manifolded to yield 300 000 Btu s Ja Ti ME na La n BESE A 2 A SER 5 l Page H eating Cooling HO water Wat Tal ark 2 Heating Only oC P 3 o Bufer 20 K Boiler H ol er T an Domestif H ot er Expansion Plate Parking Lot Brazed plate exchangers R 407C re frigerant internal circulator pumps As above with computer controlled operation 100 Gal Buffer tank 6 shown at left serves as the distribution tank for heat pumps 4 and 5 when in the cool ing mode 100 Gal Buffer tank 7 serves as the distribution tank for all 5 heat pumps when in the heating mode for
3. Maritime Installation Geothermal Ltd Manual NORDIC models DXW 45 55 65 DX to Water Direct Expansion Heat Pumps mabe ol Contents A pitt rnm Refrigerant Filled Copper Heat Exchanger Loop Hot Water Output Maritime Geothermal Ltd P O Box 413 Email nordic atcon com Petitcodiac N B E0A 2H0 www discribe ca nordic mgmain htm 12 Feb 00 Maritime Geothermal Ltd A NORDIC Direct Expansion Heat Pump System Energy Input Solar Geothermal Storage System Earth s Mass HEATING Extraction amp COOLING Rejection System DX heat pump Heat Distribution Ductwork and or Infloor Heating NORDIC DX to Water gt CE NORDIC DX to Air Maritime Geothermal Ltd 12 Feb 00 NORDIC DXW Heat Pump System Prerequisites There are four specific parts or sub systems to a DXW heat pump installation ER L aad TI Horizontal Loop Fields The successful application of a DXW heat ae Mies z on A the machine correctly for 5 a K a the home or area to condi tion and pro 2 viding enough m land area or m volume of earth a from which to 1 extract or reject heat DXW heat pumps react 1 with the earth much like a gt conventional reversing heat pump and closed loop plastic earth heat ex
4. ww DF or DC or DXW Heat Pump lines min ZONE 1 ZONE 3 ZONE 2 ZONE 4 Page 4 Maritime Geothermal Ltd Introduction to DXW Technology Direct earth coupled heat pump or DXW heat pump is one that has its refrigerant evaporator condenser in direct thermal contact with the earth from which heat 1s either ex tracted from during the heating mode or introduced to during the cooling mode of operation The general refrigeration cycle of our DXW machine is similar in nature to a conventional water to air or water to water heat pump in that there exist a compressor expansion device reversing valve and refrigerant to air heat exchanger Conventional technology concerned with heat pumps re lies upon the transfer of heat from the ground by means of a secondary heat exchanger system and working fluid e g wa ter which is pumped to the geothermal unit located in the heated structure The conventional heat pump has it s own internal primary heat exchanger which extracts heat heating mode or rejects heat cooling mode from this water which is then pumped back to the earth to be reheated or cooled DXW systems similarly use a ground coil system how
5. Pressure testing linesets Using the 1 4 schrader valve supplied on each loop the installer can again check the pressure on each lineset with his refrigera tion gauge set before re leasing the pressure and a 3 cutting the loop stubs coming into the basement to the proper lengths Interconnecting tubing Once the outside loops have been installed it is necessary to interconnect the gas and liquid lines of each loop coming into the building to its corresponding line on the heat pump Each set of two pipes is labeled on the DXW heat pump as loop 1 liquid loop 1 vapor etc depending on the tonnage of the heat pump The larger of the two pipes is the gas line 1 2 OD while the smaller line is the liquid line 3 8 OD The dealer must install a 1 2 OD gas line from each of Page 9 12 Feb 00 Maritime Geothermal Ltd NORDIC DXW Horizontal Trench Design Elevation View a Next trench line Next trench line n 1 2 soaker hose 6 ft Backfill 6 or more by hand with heavy dense material if excavated w ri Undisturbed nudn 1 2 Type Type LY or Soil A might damage the K copper pipe placed Mog in each corner i 10 ft 4 ft gt lt 10 ft gt IMPORTANT NOTES Horizontal style pipe runs should be placed 6 deep x minimum of 48 wide trench as shown above Hand backfilling in the area just over the copper pipe is recommended to pre
6. and the ROM chip See diagram A Possible settings are 1 Both jumpers removed 2 loop system 2 Left jumper only 3 loop system 3 Right jumper only 4 loop system 4 Both jumpers installed 5 loop system These jumpers are normally set at the factory and would Page 12 Feb 00 only be altered by a dealer in the case of an initial setup of a replacement control board etc Reset Pins The NCB can be reset by shorting the two pins shown in the diagram opposite Default Jumper If the service man wishes to return the onboard memory settings to the factory default settings he need only pull the connector shunt off the default pins for 10 seconds After 10 seconds replace the connector to restore operation at default level RS232 Connector The NCB controller is a full 8 bit computer capable of communicating with a terminal program to allow the installer to change a range of settings on the heat pump if required for special conditions Attachment of a serial cable to the appro priate pins on the board and running a computer terminal pro gram on a laptop etc will allow the service man to view lo cally or at a remote location the following 1 All the time delay settings 2 Loop run times 3 Soaker hose run time 4 Total operating hours 5 No of automatic resets Outputs In keeping with the philosophy above of keeping the 24v ac control power out of the NCB the outputs of the controller board are
7. ever the working fluid is a refrigerant and the copper ground loop is the primary heat exchanger Such geothermal heat ex change 1s an efficient and effective way of achieving heat ex change in heating and air conditioning systems and especially heat pump type systems Since the ground temperature is rela tively constant at 48 F at a depth 6 ft below the frost line the available heat 1s constant The elimination of the secondary earth heat exchanger typically plastic in nature and its associated working fluid reduces the temperature difference required between the ground and the evaporating refrigerant yielding a higher suc tion pressure than a conventional system under similar cir cumstances and thus a higher efficiency Many attempts have been made in the past to develop suc cessful direct coupled heat pumps for residential and commer cial uses These attempts have failed adequately to meet a number of requirements associated with an economically and functionally viable system Some of the shortcomings 1n cluded 1 Inadequate oil return to the compressor primarily in the heating mode 2 Inadequate evaporator length and spacing for properly extracting heat from the earth resulting in low capacity and low efficiency of the systems 3 Refrigerant charges in the range of 10 times greater than a similar capacity conventional geothermal heat pump 4 Approximately 3 times as much refrigerant required in the cooling mode as 1
8. liability shall be at it s option to repair or replace any part or component which is returned by the customer during the applicable warranty period set forth above pro vided that 1 MARITIME Geothermal LTD is promptly notified in writing upon discovery by the customer that such part or component fails to conform to this war ranty 2 The customer returns such part or component to MARITIME GEOTHER MAL LTD transportation charges prepaid within 30 thirty days of failure and 3 MARITIME GEOTHERMAL LTD s examination of such component shall dis close to it s satisfaction that such part or component fails to meet this warranty and the alleged defects were not caused by accident misuse neglect alteration 1m proper installation repair or improper testing Page 32
9. liquid line must be run from each heat pump liquid line to the corresponding liquid line of each groundloop Note that there is a transition in size from 3 8 to 1 2 as the liquid line attaches to the groundloop stub coming into the basement A suitable reducing coupling can be purchased from any refrigeration wholesaler The tubing used for this procedure must be refrigeration tubing cleaned amp dehydrated suitable for the job Every ef fort must also be made to insure that the tubing does not be come contaminated during installation We recommend that caps be placed on the open ends of tubing immediately after cuts are made and that these caps are only removed after all bends have been made and the pipe fixed 1n its permanent lo cation ready to make the silver soldered joints It is very im portant to keep a refrigeration system perfectly clean and dry therefore removing the caps just prior to silver soldering will insure that the tubing 1s exposed for a minimal time to the at mosphere and the associated moisture contained therein Insulating linesets All tubing inside the basement must be insulated with 3 8 wall armaflex or equivalent insulation to prevent condensa tion and sweating during winter operation Silver soldering linesets Once all the tubing runs have been routed insulated and fastened in place the caps can be removed couplings applied or alternately the tubing can be swaged and the joints sil ver
10. warrants that the compressor shall be free of defects in materials and workmanship for an additional period of 48 FORTY EIGHT MONTHS from said date MARITIME GEOTHERMAL LTD shall at it s option repair or replace any part or parts covered by this warranty which shall be returned to MARITIME GEO THERMAL LTD transportation charges prepaid which upon examination proves to be defective in materials or workmanship Replacement or repaired parts and components are warranted only for the remaining portion of the original warranty period This warranty is subject to the following conditions 1 The NORDIC heat pump must be properly installed and maintained in ac cordance with MARITIME Geothermal LTD s installation and maintenance instruct ions 2 The installer must complete the Installation Data Sheet have it endorsed by the owner and return it to Maritime Geothermal Ltd within 21 days after the in stallation of the unit 3 It is the responsibility of the building or general contractor to supply tempo rary heat to the structure prior to occupancy These heat pumps are designed to pro vide heat only to the completely finished and insulated structure Start up of the unit shall not be scheduled prior to completion of construction and final duct installation for validation of this warranty If the heat pump manufactured by MARITIME GEOTHERMAL LTD fails to conform to this warranty MARITIME GEOTHERMAL LTD s sole and exclusive
11. faulty water erating see if shaft is turning Use an amprobe to measure current draw Blockage or restriction Check water flow and power Remove obstruction in water in the water line or hot to pump Check water lines for lines Acid treat the domestic water heat exchanger _ obstruction hot water coil Thermostat limit is Check contact operation Replace thermostat if faulty open Should close at 120 F and open at 140 F Disconnect switch open Check both line and load sides Replace blown fuse or breaker or fuse blown in electri of fuses If switch is open de or close switch cal supply to hot water termine why tank Reset button tripped on Check voltage at elements Push reset button hot water tank with multimeter Thermostat on hot water Visually inspect the setting Readjust the setting to 120 F tank set too low Should be set at 120 F Heat pump not running Note the amount of time the Temporarily turn up the tank enough hours to make heat pump runs in any given thermostats until colder sufficient hot water hour weather creates longer run cy The Dole flow control is a simple self cleaning device designed to deliver a con stant volume of water from any outlet whether the pressure 1s 15 psig or as high as 125 psig The controlling mechanism con sists of a flexible orifice that varies 1 s area inversely with pressure so that a constant flow 1s maintained In line Flow
12. it should be unpacked to determine if any damage has occurred during shipment Any visible damage should be noted on the carrier s freight bill and a suitable claim filed at once The heat pump 1s strongly constructed and every effort has been made to insure that it will arrive intact however it is in the customer s best interest to examine the unit thoroughly when it arrives Optimum Placement The location of liquid to water heat pump inside the home should be determined by 1 The ease at which piping runs can be connected to the infloor heating headers on the output side of the unit 2 Space availability in a mechanical room for the hot water distribution tank and associated pumps etc 3 Ease of access to the water well supply and discharge lines or groundloop lines If possible the four main service doors should remain clear of obstruction for a distance of 2 two ft so that servicing and general maintenance can be carried out with a minimum of difficulty Raising the heat pump off the floor a few inches is generally a good practice since this will prevent unneces sary rusting of the bottom panel of the unit We recommend that the heat pump be placed on a piece of 2 Styrofoam covered with 1 4 plywood The Styrofoam will smooth out any irregularities in the cement floor while the plywood will distribute the weight of the NORDIC unit evenly over the Styrofoam This process will also deaden the compressor noise emitted f
13. normally required and during the heating mode all the loops are active Liquid refrigerant passes from the air handler section through the bi flow filter drier and through the cooling TX valve which 1s fully open by virtue of it s equalizer line being connected to the common suction inlet line and it s controller bulb attached to the vapor inlet line hot in heating mode of the air handler Liquid refrigerant then travels towards the liq uid line header solenoid valve and check valve assembly So lenoid valve A is a normally open valve and is de energized during the heating mode thus refrigerant can travel unre stricted through the heating check valves B C D E towards the inlet of all the heating TX valves Each heating TX valve is equipped with a small bypass capillary tube which allows approximately 1 2 ton of refriger ant to flow regardless of the position of the TX valve This by pass is intended to perform 2 functions e Limits the amount of hunting done by the TX valve due to the long evaporator length e Prevents the heat pump from tripping out on a high pres sure limit if all the heating TX valves decide to close at the same time The TX valves control the flow of liquid refrigerant to it s loop by virtue of the sensing bulbs being attached to each respective return vapor line and all the equalizer lines con nected to the common suction inlet line The sensing bulb of each TX valve is located just below the
14. soldered with 5 silfos NORDIC absolutely requires that dry nitrogen be bled through the system during all silver soldering procedures so that no oxidation occurs on the inside of the copper tubing Vacuuming system When silver soldering is finished the entire system should be pressurized to 100 psig with dry nitrogen and all joints Page 12 Feb 00 made by the installer checked for leaks using soap suds or some other technique that the installer feels comfortable with It is important not to bypass this step since vacuuming the system with a leak will be impossible and attempting to do so will introduce moisture to the system making the process take much longer to vacuum after the leak has been found and re paired Vacuum the system until the reading on an electronic vac uum gauge stays below 500 microns for a period of 5 minutes after the vacuum pump is shut off and the system sealed Charging system Once the system has been vacuumed refrigerant can be added by weighing in 1 3 of the prescribed refrigerant charge into the low side of the system Start the heat pump in the heating mode and continue to add refrigerant as a liquid at a rate of no more than 1 lb per minute until the prescribed charge is reached Alternately before the machine is started the entire charge can be weighed into the system through the high side schrader valve Hot Water Connections Connection to the hot water generator feature of the he
15. the entire system are shown as 8 at left 18 Maritime Geothermal Ltd 12 Feb 00 NORDIC Series DXW 45 55 65 A U ENE EEE a EEE HEEE A March 98 Pace 19 12 Feb 00 Maritime Geothermal Ltd Maritime Geothermal Ltd Revision 1 35 Color Caissie Grey Direct Expansion to Water Heat Pumps Models DX W 45 55 65 Style Horizontal Date March 1998 Drawn By G Kaye Title Cabinet amp Piping Layout Receiver Brazed Plate or Coaxial Heat Exchanger Accumulator Compressor Electrical Box es Front O O TXV Bank e Unit cabinet constructed of 20 gauge satin galvanized sheet metal Reinforcing devices placed in all high stress areas 3 Way Valve Bank e All components are easily accessible through Back Left four full length removable doors Cabinet is fully insulated with flame retardant accoustic material gt gt 3 4 ID Domestic Hot Water Lines Optional Control System Connection 1 2 diameter hple 18 3 Thermostat Wire 24VAC Refrigeration 3 8 OD Liquid Lines Service Ports Electrical Supply for Internal 26 Circulator 14 2 Wir 115v 1 Phase 60 Hz NA Electrical Supply for Heat Pump O 12 3 Wire 575v 3 Phase 60Hz 1 ID Main Buffer Tank Connections 1 2 OD Vapour Lines 1 diameter hole
16. the system and it must be rectified if the unit is to maintain good service Lock out function DXW heat cool machines See Microcontroller function manual page for complete information on the function of the controller board during lockout Electrical The NORDIC unit is supplied with an opening for 3 4 conduit nipple on the right side of the unit An additional 1 2 knock out is also supplied to accommodate accessories which may be attached to the heat pump s relays such as electronic air filters humidifiers etc Above the accessory knock out is another 3 8 hole for the thermostat wire A wiring diagram is located on the electrical box cover for quick reference and although the connections to be made are quite simple Mari time Geothermal Ltd recommends that a properly qualified electrician be retained to make the connections and wire the thermostat Starting the Heat Pump BEFORE starting the heat pump the following areas should be rechecked to assure proper operation 1 Check all high voltage field wiring and electrical connec tions inside the control box for good connection 2 Check all low voltage thermostat to make sure they are connected properly Place thermostat HEAT OFF COOL switch in the OFF position 3 Turn on the main power switch Allow the power to re main ON without starting the unit for a period of 4 hours Refrigerant migrates to the compressor oil when the com pressor is unheated A crankcase heate
17. unit is equipped with a scroll compressor which must rotate in the proper direction After initial connection start the compressor while observing the suction and discharge pressures with a refrigeration guage set If the compressor is not pumping reverse supply conductors L1 and L2 and then recheck Reversing any two of the three input wires to a three phase motor will reverse the direction of the motor Page 26 Maritime Geothermal Ltd 12 Feb 00 Maritime Geothermal Ltd Electronic Controller Board for DXW Heat Pumps Theory of Operation The Nordic DXW heat pump operates on the principle of a buried multi loop condenser evaporator assembly to ex change energy to and from the earth as required by the sea son When heating is required the heat pump uses all loops typically 1 per ton in parallel to extract heat from the ground During the cooling mode when the buried loops are acting as a condenser the number of loops in operation at any one time must be controlled in accordance with their tempera ture for proper operation of the heat pump To accomplish this Maritime Geothermal Ltd has de signed an electronic control board to monitor and control all aspects of the DX heat pump operation The NORDIC CONTROLLER BOARD hereinafter called NCB has been designed to operate the heat pump with the highest reliability and efficiency without the main micro processor being directly connected to the heat pu
18. D Dolo Jumper Loop Switch Activating LED x7 te Reset No of ROM RAM Low Pres Loops 2 Lockout LED a Loop Switch U S 2 Working U Mi O ICroprocessor Prop erly LED Low Pres Ctrl S Loop m Switch O Rx RS232 High Pres Ctrl 5 e A Communica TI High Low Heart en tion Port Pres Pres Beat Lockout LED IN l 2 3 4 5 SH JE O G Y Equipment Loop Status ON LED s ed Activates loop 1 through 5 T7 Cooling loop solenoids Soaker Hose E Emergency Heat O Reversing Valve G Blower DX to Air models Y Compressor R 24v Hot C Common 24vAC Page 28 Maritime Geothermal Ltd compressor contactor supply By moving the selector switch COOL a 24v signal on the between R and O terminal indicates that COOLING mode has been entered which activates the reversing valve the NO liquid line solenoid and 1 cooling loop When Y and R are subsequently made by a contact closure of the stat the compressor 1s activated There are adjustable time delay s built into for every function that the NCB looks after These time delays can be changed in the field by a serviceman with a laptop computer and a serial cable A list of printouts available from the NCB are included in appendix High amp Low Pres Controls and Loop Pressure Limit Switch INPUTS The NCB has another terminal block on the middle left side which accepts inputs from the high amp low refrigerant pre
19. D indicator will be ON CONTINU OUSLY The system can be reset from a permanent lockout by shorting the RESET pins or by interrupting power at the unit s main breaker Both the OFF cycle time delay on lock out and the num ber of automatic resets before permanent lockout are adjust able individually for the HIGH and LOW pressure controls Page Maritime Geothermal Ltd EG You could have auto reset LOW pres and 4 for HIGH Delays are separately adjustable The lock out counter will reset itself to 0 after a prede termined time set 8 hours adjustable so that 1 lock out in August and 2 in September will not cause a permanent lock out a month later on the 1 lock out which occurs at that time The NCB will ignore a low pressure condition for a pre set time on initial start up This feature allows refrigerant to reposition itself and begin to circulate in the system without producing a lock out in the unit On DX to air units the preset is five minutes but on DX to Water units this setting is changed at the factory to 0 minutes delay so that the water heat exchanger would not be frozen and damaged if circulation was lost during water chilling mode ON DX to Water units the factory setting for auto matic resets is set at 1 for the same reason as above Method of Operation Cooling Mode Checkout The NCB was designed to handle the unique situation of multiple parallel groundloops which occurs in the NORD
20. IC direct expansion system and as such incorporates features which are unique to our controller board Move the SYSTEM selector switch to the COOL posi tion The reversing valve NORMALLY OPEN liquid line solenoid and 1 groundloop will activate followed by the blower If the system has been in the HEAT mode there will be a delay as the MODE switch timer keeps the compressor OFF for 5 minutes adjustable The compressor will start and be gin to cool using only 1 of the possible loops available MODE 1 The controller board keeps track of the actual run time hours and stores this information in non volatile mem ory Eventually the head pressure will build up in 1 loop and activate the loop pressure limit switch which will close and send a signal to the NCB to switch to loop 2 This procedure will be repeated until all the loops have been used once If a further pressure signal is received then the NCB calculates the average run time on the loops used If the average 1s less than the MODE switch time 15 minuets factory set adjustable the controller board will advance to MODE 2 which will be gin to use 2 loops at a time If the advancement to MODE 2 produces a low pressure lock out situation the NCB will automatically shut the com pressor off for a predetermined period of time back up one MODE and try again after the timer has run out NOTE The number of automatic resets amp time delays on low and high pressure in the coolin
21. QUIRED a 10 ft 10 ft JK 10 ft Diagram at left shows another possible aN configuration for a horizontal DX piping system e Each loop should encompass about 2500 to 3500 sq ft of land area per ton of heat pump e Each loop consists of 350 ft of 1 2 copper tubing e The pit could be a excavated area or an existing area which needs to be filled as part of general excavation e Loops should be buried approxi mately 6 ft underground for best performance Example BO ft Nordic DX 45 should have 3 loops as shown at left a DX 55 4 loops and a DX 65 5 loops Other configurations would work as well such as a 50 ft x 50 ft pattern or a 60 ft x 45 ft etc The object is to encompass at least the minimum area mentioned above with spacing no closer than 8 ft between any two pipes Home Page 14 Maritime Geothermal Ltd The only difference between a Direct Expansion heat pump and a conventional geothermal unit is the fact that the NOR DIC unit has it s heat exchanger embedded in the ground Due to some engineering obstacles involved with remote parallel evaporators some special equipment and techniques which are described below are required to allow such a sys tem to work effectively 4 Ton System Description Heating Mode All NORDIC DXW systems utilize multiple earth loops to transfer heat to and from the ground One loop per ton of capacity is
22. R and W is made Nor mally used to control a back up plenum heater on a DX to Air machine however could be used to acti vate any secondary source of heat 4 L Lock out indicator status A 24V AC indicator lamp wired between C and L will flash at a rate of once per second if a HIGH or LOW pressure re frigerant cut out is OPEN The light will be on steady if there is a permanent lock out of the sys tem 5 C common side of 24v AC transformer To activate the unit in HEATING mode the aquastat need only to make a connection between R and Y The compressor will start along with the condenser circulator pump if it has been wired to the AUX relay which is supplied by power via a separate line On lower voltage models equipped with 220v single or three phase main circulators 220v circulator pump power can be obtained directly from the 21 12 Feb 00 Maritime Geothermal Ltd NORDIC DX Solid State Control Board Diagram A Selects the No of loops that termo stre Comec onb lock The board controls 2 5 2 Short Pins to Reset Restore l P Da yil Jumper if no B terminal CRLQWYBG e D O O Oh
23. at pump is accomplished by teeing into an electric or oil fired hot water tank with a capacity of 40 gal minimum A typical piping diagram is shown elsewhere in this manual Be sure to note the position of the check valve and the direction of water flow One should be sure the tank is filled with water and is under pressure before activating the heat pump to insure proper lubrication of the circulator pump Slightly loosen the copper union on the hot water discharge pipe to allow air to escape from the system before the unit is started This step will make certain that the water circulator is flooded with wa ter when it is started Since the pump is water lubricated damage will occur to the pump if it is run dry for even a short period The union on the discharge water line may have to be purged of air several times before good circulation is ob tained A hand placed several feet down the line will sense when the water is flowing The thermostats on the hot water tank should be set to 120 F since the heat pump has an internal thermostat set at a low of 130 F By setting the tank thermostats as de scribed the heat pump will try to keep the tank above the cut in point of the electric element settings thus generating hot water from the heat pump only During periods of high demand the electric elements will energize to help make hot water Safety Controls The NORDIC heat pump has three built in safety con trols which are designed t
24. changer Heat that is available to the unit must travel through the earth and therefore the conduc tion capability of the earth in the location of the 3 x 350 8 000 ft 4 x 175 4 x 350 10 000 ft 4 x 175 5 x 350 12 500 ft 4 x 175 Note These are minimum loop field requirements based on an earth temperature of 45 F heat exchanger is very important A unit used en tirely or primarily for heating will have no problem Page The source OF energy lt iskan kan enlane k sa neek ene ak ne SEO AG SNC ONE as 5 54c5 2ika0 y55554kewakene krnienakev k Converting the energy to a useable form Distributitie the NEAL Lan nk a5145455 a0 0a1 4e kab kn kai a k YY S Pbatntu Heat Pump st ato Hot Water radiant slab Solar amp Geothermal The Earth s mass with conduction and heat transfer since it will be cooling the loop during heating mode which draws moisture towards the coils because they are colder than the surrounding ground Horizontal loop fields should be laid out so that the copper coils have good cross sectional influence on the minimum ar eas listed above As a general rule wider spacing between the loops so that they do not influence one another will result in improved performance of the Nordic DXW 45 will heat up to 1500 sq ft Nordic DXW 55 will heat up to 2200 sq ft Nordic DXW 65 will heat up to 2800 sq ft Assuming a
25. connection to the 3 way valves on the gas line header assembly The liquid refrigerant coming in contact with the warm earth vaporizes to a gas and flows back to the heat pump via the 1 2 OD copper return vapor lines System oil is entrained in by the velocity of the return gas and 1s continuously swept back towards the compressor Refrigerant vapor normally picks up from 5 to 12 F superheat as it returns to the heat pump Refrigerant vapor enters the 3 way valve header as sembly at ports F passes straight through the valve to ports G where it exits to the vapor line header From the vapor line header the refrigerant gas enters the reversing valve at point H and exits to the common suction line I where it travels to the accumulator and onward to the compressor Hot high pressure refrigerant gas enters the desuperheater coil on units so equipped where a small portion of its heat is re moved in the production of hot water The hot refrigerant then enters the air coil where the refrigerant vapor is condensed by the process of cool household air flowing across the air to refrigerant coil Further sub cooling of the refrigerant liquid Page 12 Feb 00 takes place as the refrigerant reaches the bottom of the coil and begins another cycle General Operation Cooling Mode During the cooling mode of operation the NORDIC DXW heat pump takes control of the earth condenser coils and allows the most efficien
26. d to cooling mode Page 23 12 Feb 00 Locate open control and deter mine cause Replace faulty control if necessary Microcontroller board shows RED high pres or GREEN low pres lockout flashing or glowing steadily Check refrigerant level Check anticipator in thermo stat Make sure setting is for longest cycle or max amps Control should reset automati cally Heat pump can then be restarted by resetting the lock out relay Turn power off then back on Replace faulty con trol if 1t will not reset Add refrigerant slowly Check for possible leaks Normal charge is 3 to 3 5 Ibs per ton Replace TX V s if not operat ing properly Verify refrigerant flow path and check cooling TXV for proper operation Check temp difference across water coil to verify refrigerant returning Check or replace valve sole noid and if necessary replace entire reversing valve assem bly 12 Feb 00 Maritime Geothermal Ltd Thermostat not set to signal Turn aquastat down operation Low or no wa Open control circuit ter chilling Reduced water flow or Check for return water temp too 1 Blocked water lines 1 Replace filter cold Unit trips out on 2 Circulator pump not operat 2 Replace circulator pump low suction pressure ing control 3 Blocked strainers or filters Insufficient hot Circulator pump not op Visually inspect the pump to Replace if
27. e heat pump uninsulated to pick up heat in the header trench as long as the header trench is more than 12 out from the building 40 ft BUILDING Page 12 Maritime Geothermal Ltd if the refrigerant evaporating pressure drops below 20 psig Some possible causes for a trip out on low pressure are 1 Ruptured or broken groundloop coil 2 Low refrigerant charge 3 Frozen water coil in cooling mode 2 High pressure control The second safety control is a high pressure safety limit which monitors compressor discharge pressure This device will not normally trip unless there is an interruption in air flow Such a situation could occur if the blower motor or fan belt failed or if the heat pump had an extremely dirty air filter 3 Low Temperature The low temperature control located on the outlet of the evaporator in cooling mode shuts the machine off if 1 Water flow is restricted during cooling mode 2 Output water is too cold The following paragraph applies to heating only ma chines If either of these controls trips it will activate a lock out relay which prevents the unit from restarting until power to the control circuit 1s broken by turning the thermostat to the OFF position and then back on again or the electrical supply to the unit is broken by opening the heat pump breaker and then closing it again If one of these controls trips there is a serious problem with
28. ever the board is powered up to indi cate NORMAL system operation One additional yellow LED located near the upper right corner of the NCB will light whenever the loop pressure limit switch closes Method of Operation Heating Mode Checkout When the aquastat has been connected and the system powered up move the selector switch to heat mode and turn up the aquastat The compressor will cycle ON The system will remain on until the aquastat 1s satisfied or the MODE switch is changed Once the aquastat is satisfied the compressor will shut OFF A short cycle timer will keep compressor OFF for 2 minutes adjustable between cycles and 5 minutes between a changeover from HEATING to COOLING High Low Pressure control operation If a high or low pressure situation occurs within the sys tem at any time the NCB will shut down the compressor for 5 minutes during HEATING mode adjustable and 30 minutes during COOLING mode adjustable During the time that the pressure control 1s actually OPEN contacts open the LED will flash at a rate of once per second When the control CLOSES the LED will go out but the compressor will re main off until the timer has expired before compressor opera tion resumes The NCB keeps track of the number of times that the system has locked out and after 3 lock outs adjustable with automatic resets the NCB will lock the sys tem out permanently When a permanent lock out has oc curred the appropriate LE
29. g mode is adjustable the default is 3 The NCB will always advance to loops which have been unused the longest Similarly if MODE 2 cannot reject the heat pump s heat to the ground without tripping the loop pres limit switch then the NCB will advance to MODE 3 which turns on the soaker hose in a horizontal loop situation 30 Maritime Geothermal Ltd 12 Feb 00 The SOAKER HOSES provide increased cooling of the counter automatically field by increasing the moisture content and thus the conduc tion of the loop field Water is controlled via a 24 volt AC solenoid valve attached to city or well water NOTE Soaker hoses should be installed on all horizon tal groundloop fields as per the manufacturers instructions The soaker hose will stay on continuously for a predetermined period of time set 12 hours adjustable even if the system is turned to HEAT and then back to COOL Memory Functions 1 Switching from HEAT to COOL will not affect the MODE the heat pump was in during the cooling mode The unit will return to the same loops 1n which it was operating before the switch occurred 2 After a period set at 2 weeks adjustable if cooling has not been used the NCB will reset the cooling MODE to MODE 1 automatically 3 Retains loop settings and run time on each loop or set of loops as per the MODE setting 4 Stores all lock out information and resets lock out DC or DF Series Heat Pump Lines C and D can be run to any dev
30. ice that requires hot water such as infloor heating car wash laundry or commercial kitchen See other diagrams in this section for further details on typical plumbing schemetics Pressure Relief Valve PRV Taco Model 0011 7 Aquastat High Velocity Pump Insulated Tank 40 to 160 F Thermometer C A Check Valve Minimum lines Important Instructions 1 Diagram above shows the proper manner of plumbing a tank that has only 2 ports 2 The tank must have at least 1 1 4 fittings at A to accomodate the flow from the heat pump and the floor circ pump when both are in operation 3 The water line between A on the tank and the tee at B should be at least 1 1 4 4 Install a check valve at C and D to prevent backflow through the floor system or the heat pump when only one of the two pumps is running 9 Tank should have an additional 3 4 fitting at M to allow for an imersion well style probe thermostat Page 31 12 Feb 00 Maritime Geothermal Ltd LIMITE D WARRANTY MARITIME GEOTHERMAL LTD warrants that the heat pumps manufac tured by it shall be free from defects in materials and workmanship for a period of 1 ONE YEAR after the date of installation or for a period of 1 ONE YEAR AND 60 SIXTY DAYS after the date of shipment whichever occurs first In addition MARITIME GEOTHERMAL LTD
31. les e Install spacers to keep the pipes separated as far as possible from one another in the boreholes e Install 100 120 ft of dual tubing 1 2 vapor amp 3 8 liquid Recheck pressure on lines Secure pipes through opening in borehole head Backfill with pea gravel to 30 ft from top Seal hole with bentonite T a clay from 30 ft to surface e Install linesets from well heads in horizontal trenches to heat pump in building Silver braze all joints with 5 silver solder using dry nitrogen to purge the system When all joints are complete pressurize the entire system with 150 psig nitrogen and recheck for leaks Vacuum until system stays below 500 microns for five minutes after vacuum pump has been shut off Charge the prescribed amount of refrigerant through the high side schrader valve located on the front of the machine ae A Pinch around pipes and silver braze Keep pipes up 1 2 off bottom to insure good flow kar 7 8 Stub Cap Copper Page 6 Maritime Geothermal Ltd Easier to sell Systems can be quoted more accurately and easily since there 1s less outside subcontracting involved Excavation or drilling contractors know in advance what is required and can quote definite prices whereas with well drilling for open loop systems the well price may eliminate the sale entirely Installation Instructions Unpacking When the heat pump reaches it s destination
32. ly 2 0 Reversing valve COOLING mode 3 Y Compressor Other terminals which are available such as G B W L and C are normally not required with a DXW unit but are required for a DX to Air unit The functions of these termi nals are as follows and may be used by the installer if re quired 1 G Blower DX to Air models 2 B Indicates to the board that the unit is in HEAT ING mode NOTE the NCB has an optional see Jumper if no B on diagram shunt available which allows the board to generate its own B sig nal if the thermostat does not provide one The B signal is over ridden only by a signal to O In most DXW installations you will leave this shunt in place and the unit will therefore be in HEATING mode whenever O is not activated When the B terminal is generated by the board there is no real OFF Therefore to reset a permanent lock out by the NCB you need to short the RESET pins or turn the main supply power OFF and back ON again By generating our own B terminal the DXW machine can be operated with only 2 digital signals in a building that is run by a computerized building management system reducing overall control point cost per unit 3 W Second stage of heat The NCB will automati cally energize E on the bottom right terminal block after 35 adjustable minutes if the aquastat has not been satisfied E will also be energized if a contact closure between
33. meter Page 24 Maritime Geothermal Ltd 12 Feb 00 NORDIC DXW 45 55 65 HACW Series Schematic 380V 3 Ph 50 Hz Gna TI a T1 a T2 T2 380 3 50 qQ Compressor gt T3 I3 Intermediate 380v transformer AA Aux Relay 120v Thermostat 135 F max Control 120v transformer mo ez 34v 120v 1 50 Gad Circ pump relay ropa S Water o Aquastat Connections Circ pump KE Manual relay Coil Rese da Ctrl Compressor Relay CRLOW YBG Coil Y e Thermostat Connections T a k T e E Low Loop 3 e o A Ci Microcontroller Board i e e e e 0 0 7 Aux relay Coil iza Er i HILL Ai azam R 12345 S E O G Y RC i i a Reversing Valve Coil C gt Soaker Hose High a 3 3 way Solonoid Coils up to 5 Good 1 per ton Notes 1 Aux Relay A 1s included in the unit and provides a set of dry contacts for operating an external circulator pump Page 25 12 Feb 00 Maritime Geothermal Ltd NORDIC DXW 45 55 65 HACW Series Electrical Box 380v 3Ph 50Hz Models Field Wiring
34. meter shows no voltage on Determine why the disconnect Fuse blown Low voltage Burned out motor Thermal overload on compressor tripped Faulty compressor con tactor Seized compressor due to locked or damaged mechanism the line side of the compressor contactor At heat pump disconnect box switch was opened if all 1s OK close the switch Replace fuse with proper size voltmeter shows voltage on the and type Time delay type line side but not on the load side Voltmeter shows abnormally low voltage Below 210 v at heat pump disconnect switch Ohmmeter shows no resistance between common and run ter minals or between common and start terminals Note Be sure compressor overload has had a chance to reset If comp is hot this may take several hours Ohmmeter shows reading when placed across R and S terminals and infinity between C amp R or C amp S Make sure the internal over load has had time to reset Voltage on line side with con tactor held closed but no volt age on one or both terminals on the load side Points pitted or burned Compressor attempts to start but trips it s internal overload after a few seconds Faulty run capacitor Check with ohmmeter for Replace if faulty shorts open etc Page 22 D Check total load on system Call power company Determine cause and replace motor If windings are open or over load is faulty replace com p
35. mp and it s associated AC noise which can cause erratic operation We have isolated all INPUTS OUTPUTS and the POWER SUP PLY from the AC supplies in the heat pump so that AC noise is not a problem All the inputs for aquastat functions are optically cou pled to the NCB where they are transferred to a 5v or Ov signal for the microprocessor The NCB reads the voltage on each of it s inputs and determines what functions are required based on this information Aquastat Inputs NOTE The aquastat chosen should be a good quality 1 stage heating cooling aquastat By allowing the 24vAC aquastat to operate the NCB instead of the heat pump s controls directly we improve reli ability in two ways 1 The stat does not have to handle any current from compressor relays loop solenoids etc In our system direct connection to the stat could put loads on the stat which would shorten it s life With the 24v signal we send only a few milli amps of current are required 2 It is impossible to for the installer to short any thing during the installation of the aquastat Crossed connec tions etc would only activate the compressor etc 1n some er ratic manner but would not damage the controller board or aquastat The NCB has all all the time delay functions of a con Page ventional electronic aquastat built into its program The 3 terminals going to the aquastat from the NCB are as follows 1 R has 24v hot signal continuous
36. ncountered it 1s recommended that the Page 7 12 Feb 00 Maritime Geothermal Ltd Piping Layout of Vertical Style DXW Vertical Loop Field Typical 5 ton 5 loop Vertical System Another possible borehole layout with one possible borehole layout Schrader Valve Pressure Gauge 7 11 x lt 3 or larger borehole 100 ft pre made loops of 3 8 liquid line and 1 2 vapor line copper tubing U Spacers 120 ft max Charge to 150 psig nitrogen 3 8 copper 100 ft typical Check pressure again before tubing inserting into borehole and after N IV 1 2 OD tubing ete Ra i Loops can be taken to jobsite Spacer in coiled up formation and then Ss Assembly uncoiled just before insertion into borehole 050 Boreholes should be backfilled up to approx 30 ft 9 25 x 1 2 from the surface with 1 4 pea gravel thereafter to Polyethelene the surface with bentonite clay i ipe Wire tie gt 718 Stub Cap a figure 8 Pea gravel is used for backfilling material because it copper Ny fashion allows any water that may be in the borehole to _ ka nnn circulate freely thus improving the heat transfer characteristics of the hole The bentonite clay seals the to
37. nd has a holding charge of 30 psig nitrogen when the dealer receives it Materials you will need inside A lineset is required to connect the heat pump to the un derground coils which will be installed outside the structure This lineset consists of one 3 8 liquid line and one 1 2 gas line for each ton or loop installed The dealer will be re quired to silver braze 5 silfos the required indoor linesets from the point of entry to the basement or installation area to the heat pump Horizontal Trench Requirements The DXW heat pump requires one ground coil or loop per nominal ton of capacity Trenching for the DXW heat pump can be best accom plished with a tracked excavator equipped with a 44 to 48 bucket If a wider bucket is available and you can afford the extra cost the trenches could be wider for improved perform ance The object of course is to allow the copper loops to contact earth which has not been influ enced by the proximity of another loop The trenches are dug from 5 to 6 ft deep to a total length of 180 Each of the DXW loops is 350 long and when laid in the form of a U down each side of the trench the turn at the end will occur at 175 allowing for a small degree of error by the excavator op erator Take special care that the bottom of the trench is kept as smooth as possible to reduce the chance of pinching or crushing the copper tubing when backfilling the trench If rocky conditions are e
38. ne Sets Covering with sand Compacting r TA P a Enoush extra tubing has been supplied to A reach into the building when temporary plastic casing is removed Excavate alongside each borehole so that the copper tubing can lay over into the trench Water Flow Reguirements Condenser HOT Side LWT F EWT YF W 45 35 000 Btu s W 55 50 000 Btu s W 65 60 000 Btu s i 2 IN 97 gt M N NO S M 6 U T aj o 00 NO 00 N QO ON ph Page 16 Maritime Geothermal Ltd Cold Supply IN Hot Water out 12 Feb 00 Hot Water Tank Plumbing Connections Remove drain in tank and install T as shown below For DXW Heat Pumps Hot IN Hot OUT Install Plumbing as per IN amp OUT water WI2 num markings on individual heat pumps Lines C and D can be run to any device that requires hot water such as infloor heating car wash laundry or commercial kitchen See other diagrams in this section for further details on typical plumbing schemetics N Insulated Tank gt C 7 Check Valve Minimum 1 lines dua 1 40 to 160 F Thermometer Pressure Relief Valve PRV 9 B Taco Model 0011 High Velocity Pump Floor e Circ Pump A
39. o protect the unit from situations which could damage it 1 Low pressure control The low pressure control 1s designed to shut the unit down 12 Feb 00 Maritime Geothermal Ltd NORDIC Horizontal DXW Loop Field Plan View 60 ft lt sen gt 4 ton system shown SSE AE e Coiled copper tubing pome BZN ps ceces TN jhe HM o TT p e Excavated trenches minimum 4 wide x 6 deep Note Trenches will be backfilled with material which will maximize the thermal conductivity of the adjacent earth e Each loop consists of 350 ft of 1 2 OD type L copper tubing 175 ft YY e Allow a minimum of 10 ft between each trench and preferably 15 20 ft if space Is available IMPORTANT Install 1 2 plastic perforated soaker hose 2 to 4 ft below grade Manifolding done inside the building gt CA e Insulate all tubing within 12 of the structure Example with 1 2 closed cell armaflex insulation Heat Pump Building is slab on grade construction with heat provided by e Piping that is laid in a header trench should 7 hot water pumped through tubing be insulated to a point where each loop Utility Room embedded in the slab branches to it s individual trench Loop 4 shown above could be left DX to W styl
40. only a 3 borehole to a normal depth of 100 ft per ton Page 5 12 Feb 00 Maritime Geothermal Ltd NORDIC Vertical Style DXW Typical Loop design NOTE Layout for one borehole shown below Actual installation re quires one borehole per ton I E 3 holes for a DX 45 4 NORDIC DX to holes for a DX 55 and 5 for a Air or DX to Water DX 65 Heat Pump He Line h _ Vapor Line lt Trench ft NOTES e Drill vertical bore to a depth of 100 to 120 ft e Pre assemble or construct on site the dual 3 8 and 1 2 piping assem bly required Seal both ends and pressurize with 150 psig nitrogen for leak checking Silver brazing a schrader valve in the end of the 3 8 Sa ld line will allow gauge checking for loss of pressure to here Check for leaks with soap suds After a minimum 2 hr waiting period 120 ft max recheck the line for loss of pressure If the temperature of the loop hasn t changed then the pressure should be same as it was originally e Insulate both liquid lines and vapor lines from the heat pump to the well L Spacers head unless in separate horizontal trenches Vapor lines in separate horizontal trenches need only be insulated from 10 ft out in the trench to the basement wall Liquid lines must be insulated from the heat pump to approx 6 ft down the drop pipes in the vertical boreho
41. ops that are in use at the time Being able to select the correct percentage of groundloop to engage and scavenging the refrigerant from the idle loops is important for several reasons 1 It allows the to operate in both modes with one charge allowing us to disable most of the groundloop system when 1t 1s cold and reintroduce it on a predetermined ba sis as the field warms up 2 It allows the machine to switch from heating to cooling mode without shut off on it s low pressure control since refrigerant pressure is supplied to the intake of the com pressor by the idle loops while the refrigerant is being repositioned to operate in another loop or loops Once the refrigerant enters the groundloop s 1t condenses giving up its heat and returns to its liquid state Oil and liquid refrigerant are swept along the underground copper lines back to the liquid line header assembly where it flows through the cooling check valve s connected to the respective liquid lines and onward towards the cooling TX valve which meters re frigerant into the air coil as required Liquid cannot enter any of the other liquid lines because of the orientation of the cool ing check valves nor can it enter the heating section of the 15 12 Feb 00 Maritime Geothermal Ltd liquid line header by virtue of liquid line solenoid valve A Vertical DX Borehole With Cop being energized closed while in the cooling mode per U Tube Laying Horizontal Li
42. optically coupled to solid state switches so that the worst malfunction in wiring etc would produce only minor damage if at all to the output section of the control board There are 12 output connections at the bottom of the NCB located on 2 two 6 terminal connectors Terminal designa tions are as follows Left to Right Left Block 1 Cooling Loop 1 2 Cooling Loop 2 3 Cooling Loop 3 4 Cooling Loop 4 5 Cooling Loop 5 6 Soaker Hose Left to Right Right Block 7 Electric Heat 8 Reversing Valve 9 Blower 10 Compressor 11 R HOT side of control transformer 12 C COMMON side of control transformer NOTE Observe location of R and C they must not be reversed 29 12 Feb 00 Indicator LED s There are 14 LED indicator lights on the NCB which show the status of ON OFF functions being controlled by the board Each of the first 5 outputs loop solenoids has a green LED light to indicate which loops are being operated at any one time Terminals 6 through 10 above have a red LED Three additional LEDS are located near the center of the board which are from left to right 1 RED High pressure lockout indicator Flashes once per second if the control is OPEN Steady ON if the unit 1s permanently locked out on the high pressure control 2 GREEN Low pressure lockout indicator Opera tion same as above 3 Heartbeat RED Heartbeat flashes 1 per sec ond continuously when
43. ot v v py a 3 1 1 2 9 Left View K lgpm W 45 CB50 30 W 55 CB50 38 W 65 CB50 50 _ gpm __ 9 Ezan E _ Page 20 Maritime Geothermal Ltd 12 Feb 00 Maritime Geothermal Ltd Revision 1 00 Color Caissie Grey Direct Expansion to Water Heat Pumps Models DX W 45 55 65 Style Horizontal Date June 1998 Drawn By G Kaye Title Cabinet amp Piping Layout to control system 18 3 Thermostat wire Note The heat pump controls are 24VAC Electrical Knock out for Electrical Supply Knockout external circulator wiring 4 Disconnect switch _ a Left View Domestic Hot Out HACW Domestic Hot IN HACW Note all refrigerant lines sr ean should be insulated with Hot Cold IN Main Buffer Ta 1 3 8 wall armaflex Hot Cold OUT Main Buffer Tank Refrigeration Vapour Lines 28 Back View Model Minimum Circuit Recommended TD Fuse or Control Ampacity Wire Size Breaker Wire DXW 45 HACW 15 QD D DXW S5 HACW DXW 5 HACW 12 Feb 00 Maritime Geothermal Ltd NORDIC DXW Heat Pump Trouble Shooting Guide Compressor not operating Power Failure Electric circuit test shows no voltage on the line side of compressor contactor Check for blown fuse at heat pump s disconnect box or blown fuse Disconnect switch open Volt
44. p 30 ft of the hole from surface contamination thus posing no problem to the aquifer Page 8 Maritime Geothermal Ltd bottom of the trench especially the corners where the pipe will lay be covered by hand with limestone tailings or some other heavy dense material t provide a relatively smooth rest ing place for the copper pipe Unlike plastic pipe the copper tubing will stay where you put it when unrolled rather than arguing with you as plastic does on a cool day Once the pipe has been unrolled and placed backfilling by hand to a depth of 46 with fill as described above will ensure that the pipe is protected from falling rock etc during the machine backfilling procedure Other excavating devices such as a ditch witch chain dig ger or a regular back hoe can be used if ground conditions permit however you will have to dig a U shaped trench with spacing 5 ft to 10 ft We have found that the greater speed of the tracked excavator in most soil conditions and the fact that you only have to dig one trench which is excellent width for a man to work in more than compensates for it s extra rental or operational costs An alternative technique for burying the underground cop per tubing would be to dig a large shallow pit with a bull dozer This pit would have to be large enough to accommo date all the loops required in the system The copper tubes should have a spacing of at least 6 ft minimum A wider
45. r is standard equip ment on your heat pump and it will warm the compressor Page 12 Feb 00 dispelling the liquid refrigerant 4 Turn on the water supply to the hot water generator and check all plumbing for leaks 5 Check the hot water tank to be sure it 1s filled with water before energizing the circuit Slightly open the union on the hot water discharge pipe to make sure that all air 1s out of the system and the circulator pump is flooded with water Make sure the air filter is clean and in place 7 Vacuum out any dust and debris that may have collected in the unit during installation Check the condensate drain to be sure that it is free of obstruction 8 Make sure the unit is sitting level so that condensate wa ter will not overflow the catch pan 9 Make sure the proper time delay fuse has been installed in the fuse box 10 Have the following tools on hand and know how to use them 4 A refrigeration gauge set An electronic or other accurate thermometer An amprobe Connect your refrigeration gauge set After the 4 hour warm up period place the thermostat function switch in the HEAT position turn up the ther mostat The compressor blower and hot water circulator will start 3 Observe the readings on the high and low pressure gauge set When the home reaches a temperature of 65 to 70 F the suction pressure blue gauge should be approxi mately 54 to 58 psig while the head or discharge p
46. res sure red gauge should be in the area of 225 to 275 psig Record this information on the warranty test card 4 Record the return air temperature by drilling a small hole in the return air plenum approximately 2 ft from the filter rack and inserting the thermometer s sensing device 5 Similarly record the discharge air temp There should be a rise across the air exchanger of from 25 to 35 F 6 At the electrical disconnect switch place the amprobe jaws around the supply wires and record the current in each 7 Place the thermostat function selector in the COOL posi tion Placing the selector in this position energizes the reversing valve and loop 1 solenoid valves Next turn down the stat to a temperature that will cause the air con ditioning to begin The blower and compressor should operate The outlet temperature will be approx 15 to 25 F cooler than the return air temp Ne e o General Maintenance As with any piece of equipment there will eventually be some maintenance to be done on the heat pump however a DXW heat pump is relatively maintenance free and only one item will need attention as follows Check contactors for burned or pitted points Theory of Operation The DXW heat pump utilizes a typical vapor compression refrigeration cycle similar to many other common appliances 13 12 Feb 00 Maritime Geothermal I td NORDIC DXW Pit Heat Exchanger Layout ONE LOOP PER TON RE
47. ressor Replace contactor Attempt to rock compressor free If normal operation can not be established replace compressor Maritime Geothermal Ltd Compressor not operating Compressor short cycles Unit trips off on LOW suction pressure control HEATING Low or no wa ter chilling Open control circuit Low refrigerant level Compressor repeatedly locks out on it s LOW pressure safety control Intermittent contact in electrical control circuit Faulty low pressure ctrl Low refrigerant charge Faulty TXV s Refrigerant not return ing to water coil Reversing valve stuck in the heating mode Thermostat not calling for heat High or low pressure limit open Lock out relay energized Control board shows hi or low pres permanent lock out Refrigeration gauges show suction pressure dipping below 20 psig Normal operation except too frequent starting and stopping Refrigerant pressure control should open on drop at approx 20 psig Check return air temp Normal suction 1s 40 60 psig Check individual suctions to verify that each TX V opening and closing cycle is approxi mately the same Check discharge pressure and gas temp Only the gas line s that are in use indicated by the controller should be HOT Feel liquid line check valves Unit works well in the heating mode but there is no loud rush ing sound when unit is quickly switche
48. rom the bottom of the cabinet As an alternative several pieces of 2 x 4 lumber can be placed under the unit running from the electrical connection side to the filter rack side of the heat pump Laying the 2 x 4 s in this manner will give the best support since they will be at right angles with the internal steel compressor and heat exchanger supports Materials supplied by NORDIC 12 Feb 00 NORDIC supplies the DXW heat pump with all internal valving and headering pre assembled pressure tested and ready to be installed to the customers duct system and under ground copper exchanger loops The underground coil assem blies are also supplied pre tested and sealed with 100 psig nitrogen pressure A DXW system may comprise from 2 to 5 underground loops One loop is required for each nominal ton of compressor capacity The standard loops are 1 2 OD type L or K copper tubing When the dealer unpacks the coils the integrity of the loops can easily be checked by at taching a suitable pressure gauge to the 1 4 schrader valve on the coil assembly The pressure read at room temperature should be approx 100 psig 5 psig If a loop is not within this tolerance it should be set aside for retesting or returned to NORDIC for replacement Under no circumstances should a copper groundloop be used if there is any question that it may not be pressure tight The DXW heat pump unit has been high pressure tested for leaks a
49. s required in the heating mode 5 Lack of a proper means to store additional refrigerant re quired during the cooling operation but not needed during the heating mode 6 Inefficient and ineffective method to account for vastly varying condenser capability depending on ground tem perature 7 Difficulty in providing an easy to install system of earth exchanger loops The NORDIC solution has been to start with a clean 12 Feb 00 new concept and to design a unit from the ground up We started by developing an evaporator system that would yield the best performance to pressure drop factor and which would impact enough area to maintain a minimum suction pressure above 40 Psig The current horizontal groundloop comprises 350 ft per ton of 1 2 OD copper tubing A 3 ton system would have 3 such loops working in parallel during the heat ing mode Refrigerant charge had been determined to be 5 lbs of R 22 per loop These 1 2 copper loops maintain sufficient velocity at all times to insure adequate oil return During cool ing mode the machine automatically selects one or more loops based on discharge pressure to act as the condenser As the discharge pressure builds to a predetermined point the on board computer selects the most appropriate combination of groundloops to dissipate the heat at the lowest cost to the homeowner By intelligently controlling the manner in which the condenser is utilized our total system charge does not ha
50. spacing would lead to slightly greater efficiency Entering dwelling The copper groundloops must enter the dwelling at some location typically through the concrete foundation just above the poured floor An alternate method would be to run the pipe insulated up the outside wall making a 90 degree turn above ground and entering the dwelling between the floor joists just below the first floor These pipes should be insu lated with a minimum of 3 4 of closed cell weatherproof in sulation There will be two 1 2 OD copper tubes for each nominal ton of capacity of the heat pump being installed For example a 3 ton unit would have 3 groundloops and thus 6 ends to go through the concrete wall We recommend that you drill these holes to a diameter large enough to allow for the insertion of a plastic sleeve see drawing and the tubing with it s insulation jacket Suitable measures must be taken to seal the installation from water penetration before the trench is backfilled Unrolling amp Placing the Tubing Each 50 roll of tubing is taped both individually and to the next roll in the group so that at any one time only 50 of the 350 is free to unroll This allows for easier unrolling and prevents kinking the pipe Observe how the taping is done so that you know which side of the loop to start unrolling first To begin unroll approximately 12 of copper tubing Slide two 6 lengths of armaflex closed cell insulation with wall thickness of a
51. ssure controls as well as the loop maximum pressure switch These connections are pre wired at the factory and the installer need not concern himself with the connections unless he is replacing the board for some reason The connections are marked H H To and from the normally closed HIGH re frigerant pressure switch L L To and from the normally closed LOW re frigerant pressure switch A 5v DC signal is sent out continuously on one side of each of these controls If the NCB does not see 5v coming back it knows the pressure control has opened and takes ac tion to shut down the compressor S S A 5v DC signal is sent out continuously to one side of this Normally Open pressure switch The NCB 1s normally looking for a 0 voltage on the return lead If 5v is seen on the return lead then the NCB knows the switch has closed be cause of a limit pressure condition in the groundloop and will take action to switch loops There is an LED indicator light which will light when the loop pressure switch is closed This light will go out when the heat pump changes loops and loop pressure drops back below the reset pressure of this switch Other INPUTS Initial setup of the NCB requires that the board know during the cooling mode whether it is on a 2 3 4 or 5 loop system The NCB can then decide which loops to cycle and in what order This is accomplished by setting the position of two shunt style jumpers located between the microprocessor
52. t least 1 2 over the end of the tubing and insert it through the plastic sleeve of hole 1 approximately 8 into the basement It is good practice to label this line loop I gas to identify it when interconnecting linesets inside the 12 Feb 00 building Unroll the copper tubing down one corner of the trench When 175 ft of tubing has been laid out make your turn and proceed back the other side of the trench to the foun dation of the building Slide two 6 lengths of armaflex insula tion onto the tubing and insert the stub end through hole 2 M in the wall to f match the other A end of the loop Label this end of the line loop Z liquid so that the com plete loop can be identified later Manually back fill the loop with fill to a depth of 4 to 6 for protection during the machine backfill process Duplicate the process described above apply ing labels to identify the two ends of successive loops loop 2 3 4 etc until all required loops are in place Insulation Placement Near Foundation It is important to apply closed cell insulation to the copper groundloops as they come within 12 of the building to pre vent the possible build up of ice near the foundation of the home Applying 1 2 wall closed cell waterproof insulation to the tubing as described above will insure that very little heat is absorbed from the ground near the basement wall thus avoiding possible frost damage to the structure
53. t least R 20 walls and R 40 ceiling heat pump Unless you are sure there will be sufficient moisture present in the loop field area during the Summer a soaker hose is recommended in all hori zontal trench systems which will used for air condi tioning purposes Vertical Bore Systems Vertical bores 3 x 100 ft holes provide an alternate method of installing a DXW unit A high water table in the borehole area 20 to 30 ft will insure that there is er conduction with the earth and al though the loop length per ton 1s aa 11 e shorter than the gt horizontal design m the vertical orien M tation and mois ture in the bore holes very uniform con a V provides m S n Boreholes at gt W k 3 12 Feb 00 Maritime Geothermal I td NORDIC DXW Series Typical Plumbing Boiler drain Boiler Feed for Air Release Pressure Reducer TN Set 12 15 mu psig 5 xo n 2 2 Minimum line size 1 V Circulator Pump Taco 0011 or Grundfos UP 26 99 high velocity E Ball Valve O Pressure Gauge 0 30 Psig Auto or Manual Vent Thermometer 40 to 140 F e _ gt Aquastat Electric Hot Water Distribution Tank o gt zone valves LL To and form Well or Groundloop 75 100 Psig Pressure relief valve
54. t transfer of heat to the ground via an onboard computer which monitors the conditions under which the heat pump is operating and stages the earth loops into the system as required When the heat pump thermostat signals for cooling three items are energized The reversing valve The liquid line solenoid valve One or more of the vapor line 3 way valves Refrigerant is directed to one or more loops based on loop temperature and stored information in the embedded control ler Each of the loops can be used independently or in con junction with one or more of the others The controller makes decisions based on preset information concerning system ca pacity horizontal or vertical configuration amount of heating and cooling runtime etc Refrigerant leaves the compressor and enters the desuper heater coil as in the heating mode which removes a small por tion of the heat available to make hot water The gas then flows to the reversing valve and onwards towards the refriger ant vapor header The 3 way valves which are powered ON by the controller board allow refrigerant to flow into the earthloops to which they are attached Valves which are de energized remain closed at port G however flow is OPEN between ports F and H allowing refrigerant to be scavenged from the groundloops not in use Within a few minuets all the liquid refrigerant in the idle cooling loops is rerouted to the one or more cooling lo
55. ve to be altered nor does an excess charge have to be stored anywhere DXW Better than Current Technology There are several advantages of DXW technology that are superior to conventional geothermal heat pumps of both the open loop and closed loop variety Listed below are some of the reasons why DXW technology is becoming more attractive to Homeowners Dealers and Utilities More Reliable e Fewer parts to the system e Does not require a supply and return well e Does not require a well pump or circulation pumps No water heat exchanger and associated valving to cor rode freeze and break More Efficient The direct expansion principle allows the refrigerant to come directly into contact with the earth separated only by copper tubing During winter maximum heat transfer takes place at higher temperature than conventional groundloop technology without the maintenance and electrical cost of cir culation pumps Less Maintenance Only a sealed refrigeration circuit to maintain More Versatile DXW systems can be installed in a more confined area than a conventional groundloop system primarily because the heat exchanger coil is much more efficient at transferring heat to the refrigerant than a plastic earth exchanger Normal loop lengths for a DXW machine are nominally 350 ft per ton as opposed to 450 to 500 ft per ton for a plastic earth exchanger Similarly vertical systems require
56. vent crushing or pinching of the pipe during backfilling operations Individual trenches 1 per ton should be spaced a minimum of 10 ft apart to allow the best performance of the groundfield Install a Soaker hose in all trenches as per the diagram to assist in initial compaction around the copper loops and also to heat conductive moisture to the ground during cooling modeif required by the system Experience has shown that groundloop fields with the piping laid in a relatively horizontal fashion or with a slight incline uphill will have better performance in the cooling mode due to considerations concerning the flow of liquid refrigerant back to the air handler when cooling The 1 2 liquid lines must be Floor Joist S ER TE reduced to 3 8 at the point of entry to the building where N A the vertical rise begins Insulate all 4 inside lines Excavated Trench A with armaflex ea Wa Drill hole through wall approx 1 minimum larger than pipe size Seal with foam or other watertight sealant Reduce the 1 2 liquid lines s Suitable for max temp of 250 F to 3 8 here m BERR Insulate all lines within 10 ft of Basement floor basement wall with 1 2 armaflex Page 10 Maritime Geothermal Ltd the gas lines on the heat pump to the corresponding gas lines of each groundloop Similarly a 3 8 OD
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