Bryant 378 User's Manual
Contents
1. 2 ONE PILOT RELAY _ TWO PILOT RELAYS IF ANY OF THE ORIGINAL WIRE AS SUPPLIED WITH THIS APPLIANCE MUST BE REPLACED IT MUST REPLACED WITH SAME OR EQUIVALENT WIRE LOW VOLTAGE WIRE 18 A W G 4 64 THICK 600V 105 C INSULATION LINE VOLTAGE WIRE 14A W G 5 64 THICK 600V 105 C INSULATION S P D T LIMIT SWITCH 18 A W G 2 64 THICK 600V 150 C INSULATION THIS APPLIANCE IS CONVERTED TO PROPANE GAS THE INSTALLATION WILL NOT BE COMPLETE UNLESS THIS WIRING LABEL REPLACES THE WIRING LABEL SUPPLIED ON UNIT 57814 Figure 2 Wiring for Propane Gas TG x LOW VOLTAGE gt LOW VOLTAGE TERMINAL STRIP TERMINAL STRIP ON CONDENSING UNIT st 2 378 THERMOSTAT BRYANT P N 95265 _ SUB BASE BRYANT P N 95270 7 gees a Figure 3 Low Voltage Wiring 378 112. Capacity Table Water Capacity Gallons 36 450 Chiller 5 54 450 Chiller 8 36W 378 54W 378 1 5 90W 378 108W 378 Coil 3 0 1 ft of 3 4 inch pipe 03 1 of linch pipe 05 lft of 1 1 4inch pipe 08 _ Ift of 1 1 2 inch pipe 12 c With the pump operating adjust the water _ operating level in the chiller Summer Operation In general it is recommended that the methanol be flushed from the chilled water system for summer operation The presence of methanol in the chilled water will reduce the capacity with a corresponding increase in operating cost However the reduction in capacity resulting from the 5 solution of meth anol is smali less than 1 the methanol may be left in the system If the system is drained flushed and refilled with water be sure to add one box of chilled water ad ditive borax for each 20 gallons of water or frac tion thereof in the system _ Note The above explanation covers only the normal winter shut down protection If for any reason the gas air conditioner must operate when the outdoor temperatures are below freezing it will be neces sary to prepare the chilled water system for the minimum temperature Consult your Bryant disin butor for special procedures to follow EH 378 og Blower Motor MAINTENANCE LUBRICATION if equipped with 011 cups oil motor bearings with SAE 10 20 no
3. Clearance from combustibles From casing all sides and top 6 From base 0 This permits use of combustible material as sup port Caution When using rails etc as support do not enclose unit so as to interfere with drainage 4 Service clearance Front 24 Side Provide adequate side clearance for fil ter removal Clearance on left side for blower service side clearance for coil service _ Provide adequate clearance when air conditioner is located adjacent to unit INDOOR INSTALLATION _ Mounting Unit may be set flush with floor or mounted on sup ports There is no need to provide clearance under the base Shim as required to make unit level Clearances 1 From combustible materials a 0 clearance on bottom b 6 clearance from casing surface line con tact allowed c 6 vent and draft hood 2 Service access Same as for outdoor installa tion _ COMBUSTION AND VENTILATION AIR When the furnace is installed in a confined space but in a building otherwise having adequate infiltra tion from the outside air for combustion and venti lation may be taken from the building Two openings should be provided each having a free area of one square inch for each 1000 Btu per hour one located above the draft diverter relief opening and the other near the floor 6 When the furnace is installed in a building of un usually tight construction air for combustion and ventilatio
4. 378 3937809 5 10 65 GENERAL The Model 378 is approved by the American Gas Association for 1 Use with natural mixed and propane gases 2 Outdoor installation a On a roof b At grotind level 3 Indoor installation when equipped with Bryant draft hood assembly Part No 36154C8 and special front door in place of door furnished a Attic b Basement utility room etc 4 Use with 36W 54W 90W and 108W water coils 5 Use with 48R 60R 90R and 120R direct expan sion coils INSPECTION Be sure available gas supply is the same as shown on American Gas Association rating plate OC LOCATING THE UNIT Check electric supply voltage phase and fre When metaline in conjunction with a cooling sys quency to be sure that it is the same as required tem refer to the applicable section of this instruc on the rating plate Check to be sure that adequate tion for additional information power is available to handie the increased electri cal load when the unit is used for cooling Before locating the unit refer to local codes OUTDOOR INSTALLATION Installation of the all weather heating and cooling 3 unit consists of the following Mounting 1 Locating the Unit The unit design permits use of four corner posts _ 2 Gas Piping rails or any other method of support sufficiently 3 Venting strong to accommodate the weight however consult 4 Electric Connections loca
5. anged accordingly 4 Air Flow and Temperature Rise The furnace is approved for operation under the temperature rise conditions shown in Table I 120R amp 300 378 200 000 20 F to 75 F _ TABLE 36W 54W 48R 150 000 45 F to75 F 60 amp 150 378 100 000 20 F to 75 F 90W 108W 908 300 000 45 F to 75 F The pulley setting has been made at the factory to give an air flow compatible with the intended use of the equipment i e the setting varies with the type of cooling coil to be used Table II gives pulley setting as the furnace leaves the factory and shows also how the pulley can be adjusted to give the desired air flow if the duct resistance is higher than normal The static pressure against which the furnace is operating is the difference in pressures in the return air duct and the discharge duct hear the furnace If this differential pressure determined when the filters are clean and the pulley is opened the number of turns shown for normal static is more than shown for normal static in Table II the blower speed should be increased by changing the pulley setting to that shown in the column for higher than normal static pressures The temperature rise is the difference between the 1 temperature of the air in the return duct and in the discharge duct near the furnace This temperature tise measured after equilibrium has been attained sh
6. d for modulated input down to 50 000 BTUH when equipped with an approved modulating valve The size 300 furnace natural gas only is erent for modulated input down to 100 000 BTUH __ next page for Gas Input Measurement EH 378 Determine gas input as follows a Determine the number of seconds required for Input Btu Temperature Rise Air Model No perhr through Furnace the gas meter test dial to complete one revo tution b Divide 3600 by the number of seconds in Item a above Multiply result of Item b by the number of Cubic feet shown for one revolution of the 2 test dial This gives you cubic feet per hour of gas flow d Multiply result of Item c by the heating value of the gas in BTU consult local util ity for value This gives you the total meas ured input in BTUH Compare this value with that on your rating plate Example Suppose that the size of the test dial is 1 2 5 cu ft it takes 20 seconds for the dial to complete one revolution heating value of gas is 1050 ft Proceed as follows a 20 seconds to complete one revolution b 3600 divided by 20 equals 180 180 x 0 5 equals 90 cu ft per hour of gas flow d 90 x 1050 equals 94 500 BTUH input Only minor changes should have to be made at the pressure regulator If the manifold pressure must be changed more than 3 w c to obtain rated input the orifices should be ch
7. grams 208 230 VOLTS COMBUSTION 60 CYCLE gt 2 SINGLE PHASE CURRENT DRAW LESS _ THAN 12 AMPERES FACTORY Low VOLTAGE gt gt gt FIELD LINE VOLTAGE PRESS sw iy LIMIT SWITCH COMBUSTION A AIR BLOWER MOTOR Fy FIELD LOW VOLTAGE mmm FAC TORY LINE VOLTAGE BLOWER MOTOR j PILOT GAS NS RESISTOR ONE 2H moe TWO 2H PILOTS OF THE ORIGINAL WIRE AS SUPPLIED WITH THIS APPLIANCE MUST BE REPLACED IT MUST BE REPLACED WITH SAME OR EQUIVALENT WIRE LOW VOLTAGE WIRES 18 A W G 4 64 THK 600V 105 C INSULATION LINE VOLTAGE WIRES 14 A W G 5 64 600V 105 INSULATION LIMIT SWITCH WIRES A W G 2 64 THICK 600V 150 INSULATION THIS APPLIANCE 15 CONVERTED TO PROPANE GAS THE INSTALLATION WILL BE COMPLETE UNLESS THIS WIRING LABEL IS REPLACED WITH THE WIRING LABEL SUPPLIED WITH CONVERSION KIT 57389Ci _ Figure 1 Wiring for City Gases 378 EH 378 FACTORY LINE VOLTAGE Ey LIMIT SWITCH F N COMBUSTION a a 7 BAIR BLOWER 208 230VOLTS CoMBUSTION i J MOTOR 60 CYCLE SINGLE PHASE CURRENT DRAW LESS THAN 12 AMPERES FACTORY LOW VOLTAGE FIELD LOW VOLTAGE LINE VOLTAGE BLOWER MOTOR A Gas B VALVE
8. her Indoor Outdoor Unit Water Coil Connections For installation of chilled water lines from the gas air conditioner to the water coil in the Model 378 refer to installation instructions furnished with the gas air conditioner For piping and wiring recommendations on multiple gas air conditioner installations as required for the _ 90W 378 and 108W contact your Bryant distributor Winter Shut Down Protection It will be necessary to add anti freeze to the chilled water system for winter protection whether the Model 378 is installed indoors or outdoors The ad dition of the anti freeze will furnish freeze protec tion for the coil and piping It will also provide for expansion of water in the coil if the coil is located in the heated air stream EH 378 Winter Shut Down Protection continued Winter shut down can be provided as follows 1 With the pump circulating water with additive borax add one gallon of methanol uninhibited methyl alcohol for each 20 gallons of water or fraction thereof and circulate for ten minutes 2 It is not necessary to drain the system 3 Tag the unit to show methanol has been added 4 Determine the correct amount of methanol quired as follows a Estimate the system water capacity in gal lons from table below Multiply the length of pipe in feet by the gallons in one foot then add the gallons of water in chiller or chil lers and coil Water
9. l codes particularly for roof installation 5 Start up and Adjustment 6 Connection with Electric Air Conditioner when aE adel Pearce used Clearances 7 Connection with Gas Air Conditioner when 1 Provide a minimum 1 inch clearance on bottom used for water drainage rain sleet and snow s46 soos ses _ 09 _ xorddy Ton 1 0 2 Txozxsz z Txozxsz z jqesodsip sio 0 Tx0zxsz Gy 8 8 1 8 1 Lb t T JapNO LAN SUT 197V p o pinbry 10 0 JaMOTE oes PUA WAO 000 0081 001 100095 00 BUNEI 1938 000 06__ 000 OST SZz 000 OST SZZ 000 OST SzZ 000 0 lt 65 000 9 211 000 000 SZ ZIT 000 SZ ZIT youuog _ 000 002 00 000 002 00 000 005 00 000 005 00 000 00T OST 000 001 091 000 00T 0ST 000 00T 0ST mdu 86 801 BLE 9 8 5 06 8 6 3001 848 406 8 815 409 8E 8 _ LINN YOOGLNO YOOGNI NAHLVAM TIY 8 5 EH 378 Outdoor Installation Clearances cont d E Provide adequate clearance for outlet and return duct connections 3
10. ly as one with a minimum number of turns 4 Maintain a minimum of 1 4 inch per linear foot upward slope on all horizontal runs 5 Rigidly support the flue pipe with hangers and straps to insure that there will be no movement after installation 6 Extend the flue connection pipe through the chimney wall flush with the inner face of the chim ney liner Never connect into a chimney serving open fireplace unless the fireplace opening is sealed off 7 The chimney or gas vent should extend high enough above the roof or neighboring obstruction so that wind from any direction will not create a positive pressure in the vicinity of the outlet of the chimney or gas vent The installer is referred to Part V of American Standard Installation of Gas Appliances and Gas Piping ASA 721 30 1959 for detailed information on chimney and gas vent use In general the chimney or gas vent should extend 3 feet higher than the point of emergence through the roof and at least 2 feet higher than any abject within a radius of 15 feet EH 378 4 8 if more than one appliance is vented into the _ chimney the cross sectional area of the chim ney must be as large as the largest flue pipe being _ connected plus 50 per cent of the cross sectional areas of the additional flue pipes being connected 9 If more than one appliance is manifolded into the same flue connecting pipe the cross secti
11. n detergent oil each heating and cooling season Use approximately six drops for each bearing Some motors are equipped with bearings of a permanently lubricated type and therefore need no further oiling Blower Bearings are of the permanently lubricated type and therefore need no further oiling Combustion Air Blower Motor located in compartment Oil motor bearings with SAE 10 20 non detergent oil each heating season Use approxi mately three drops for each bearing Air Filter Periodically inspect air filters Replace when dirty with filters of the same size see marking on fil ters making sure that arrows on edge of filter point in direction of air flow toward blower Excessively dirty filters reduce furnace efficiency Cleaning the Unit _ 1 Be sure main line disconnect switch is in the off position Tag with suitable warning label 7 Turn manual gas and pilot valve to peer tion 3 Remove upper and lower front access panels 4 Disconnect pilot and escapement tubing 9 Remove burners 6 Remove screws holding horizontal dividing panel and flue collector in place dividing panel and flue collector up and back to give access to flue outlets 8 Remove flue baffles 9 Clean flue passages with suitable brush 10 Re assemble furnace by reversing the above procedure making sure all seals are properly re placed See following pages for Wiring Dia
12. n should be obtained from outdoors or from spaces freely communicating with the outdoors Two openings should be provided each having a free area of one square inch for each 2000 Btu per hour one located above the draft diverter relief opening and the other near the floor For further information on this subject refer to ASA Z21 30 1959 or later editions of this standard Installation of Gas Appliances and Gas Piping GAS PIPING The gas supply line should bea separate line direct from the meter to the furnace Check local utility for recommendations concerning existing lines Choose a supply pipe size large enough to keep the pressure loss as low as practi cal Never use pipe smaller than the gas connection to the furnace local codes for all gas pipe installation The following are pertinent recommendations 1 Avoid low spots in long runs of pipe It is best to grade all pipe 1 4 inch in 15 feet to prevent traps All horizontal runs should grade to risers Risers should be used to connect to the furnace and to the meter 2 Install a drip leg in the riser leading to the furnace This drip leg will serve as a trap for dirt and condensate The drip leg can be installed by connecting tee to the riser leading to the furnace so that the straight through section of the tee is vertical Then connect a capped nipple to the tee The capped nipple should extend below the level of the gas co
13. ntrols a minimum of 6 inches 3 A manual shut off valve should be installed in the gas line within sight of and convenient to the furnace This shut off valve is furnished 4 Support all piping with appropriate hangers etc Properly support gas piping at furnace to prevent damage to weather tight seal 5 After all connections are made check for leak age using soap and water solution or in accordance with local utility regulations Never use a match or other open flame EH 378 VENTING INDOOR INSTALLATION Consult local codes Unless the local codes direct otherwise the unit may be vented to a permanent chimney or to a listed Type B or Type C gas vent The Model 378 furnace is approved for indoor instal lation only when used with draft hood Bryant Part No 36154 8 To install indoor draft hood a Remove upper front access panel to gain en trance to flue collector b Insert draft hood inside furnace casing collar and push it down over the flue collector collar to form snug connection c Fasten draft hood to flue collector collar with Sheet metal screws _ The following recommendations are made 1 Select flue connection materiai that is satis factory for the installation and that meets the _ requirements of the local codes 2 The flue connection pipe must be the same size as the outlet collar on the furnace No reduction in this size is permissible in the pipe run 3 Run pipe as direct
14. o the unit on all outdoor installa tions r 26 gt a 73 Thermostat connections for heating only are to be made at terminals 4 and W See Figure 3 for low voltage _ connections when cooling equipment 15 used _ 4 A eed electrical line should be run for this installation START UP AND ADJUSTMENT 1 Betore Starting the Unit Check to see that electric and piping con nections have been made b Make sure gas piping is purged and free of air do not purge into the combustion chamber of the furnace All gas piping connections should be leak tested Do not use an open flame Use a soap and water solution 2 Start Up Follow lighting instructions attached to the unit Sequence of control operation is as follows a When pilot gas cock is opened gas flows to the pilot and to the pilot pressure switch b Pilot pressure switch then closes to com plete the 24 volt circuit The pilot then lights automatically Subsequent Switch action completes circuit through and W to energize the electric gas valve When the thermostat calls for heat circuit 1s closed between Wand 4 This allows current to flow through combustion air fan relay which energizes the com bustion air blower and builds up pressure in the combustion air switch When combustion air pres sure switch is closed low voltage is completed _ The conditioning air blower is not actuated by a fan switch b
15. on valves for the 48R and 606 378 units are supplied as a loose with the condensing unit To install the expansion valve proceed as follows 1 Remove panels from right hand side of the 378 unit 2 Remove plug from flare nut connector on dis tributor and insert expansion valve 3 Remove plug from external equalizer line flare fitting and connect equalizer to expansion valve 4 Shipped as loose parts on 48 amp 60 sizes are 2 large metal seals a neoprene gasket and nuts and nuts and bolts to seal the liquid line opening In stall air seals as shown SCREW 4 Nr e 5 Uncoil capillary line of expansion valve and attach sensing bulb to top of horizontal suction line inside of unit casing Wrap bulb with prestite tape shipped with unit as a loose part 6 Connect coil to condensing unit per instructions packaged with the condensing unit 7 Follow procedures outlined in Condensing Unit Installation Instruction for leak testing and evacua tion 8 Replace panels on unit and connect condensate located on opposite side of unit to a suitable drain site 9 All electrical connections should be made in accordance with National Electric Code and any local codes that might apply Make electrical con nections as shown in wiring diagram in condensing unit instruction and the low voltage diagram in this instruction CONNECTING GAS AIR CONDITIONER W 378 All Weat
16. onal area of this manifold pipe must be as large as the sum of the cross sectional areas of the pipes connecting into 10 Flue pipe must he at least 6 inches from any combustible materials Do not use dampers or other in flue i Any part of the vent which is outdoors must be ade quately insulated to assure proper chimney action and prevent condensation OUTDOOR INSTALLATION The Model 378 ali weather unit is shipped with out door vent as standard equipment and must be instal led in accordance with the following instructions and without alterations Installing Outdoor Vent 1 Remove upper front access panel to gain en trance to flue collector Z Insert cap and pipe assembly through furnace casing important Be sure the outer wail of the double wailed pipe extends over the furnace casing con collar to assure weather tight connection and that the inner wall connects to the flue collector collar 3 Fasten the flue pipe assembly to the flue col lector collar with sheet metal screws Note Addi tional venting is not required on outdoor units ELECTRIC CONNECTIONS 1 All electrical connections are to be made in accordance with National Electrical Codes and local codes governing such wiring Field connections to be made accordance with wiring label attached to unit See Figures 1 and 2 2 Weather tight connections must be made at elec i trical entrance t
17. ould be within the range shown in Table I The pulley setting shown in Table should give air rise within the approved range TABLE II Model No 36W 378 54W 378 48 378 60R 378 Static 108W 378 Normal Static ARI Factory Setting of _ Static Pulley Turns Open w c Open p20 05 29 37 20W 378 0 ee Higher Static Pulley Setting Turns Open The furnaces are approved for operation up to 0 50 in w c EH 378 CONNECTING CONDENSING UNIT TO R TYPE MODEL 378 The evaporator coil is supplied as an integral part of R Type 378 unit The condensing unit may be installed remotely or adjacent to the R Type 378 unit Consult Condensing Unit Installation Instructions for minimum clearances and connection of refrigerant tubing All openings in refrigerant lines from evaporator coil and condensing unit are plugged or capped to keep moisture out of the system These plugs or caps should not be removed until each connection is made Each connection should be made in the shortest time possible to avoid contamination from surrounding air Note The 90R and 120R 378 units have a factory installed expansion valve Items 1 through 5 will therefore not apply for these sizes in the following instructions The expansi
18. ut by a delay fan relay If the lower limit opens the automatic gas valve is de energized If the upper limit opens the automatic gas valve is de energized and the combustion air pressure switch is by passed so that the conditioning air blower will continue to run The automatic pilot turns the main gas off should pilot flame be put out This can be checked by turn ing the main burners and pilot on then shutting the pilot gas off The main burners should shut off The limit controls the temperature reached in the aha unit The limit will shut off the main gas if the _ temperature goes too high The limit may be checked by removing the fan belt and firing the unit The burners should shut in a few minutes 3 Adjust Gas Input Air Shutter Adjustment To adjust the air shutter pull the shutter closed until there is slight yellow tip at the top of each flame Then open the shutter until the yellow tip disappears Gas input should agree with that shown on the eating plate of the unit The burners are equipped with orifices sized to give the correct input with a mani fold pressure of 3 inches w c 0 3 for natural and mixed gases and 11 inches w c for propane gas The furnaces are approved for minimum firing rates shown on tating plate as follows Size 150 May be fired at 100 000 BTUH input Size 300 May be fired at 200 000 BTUH input Note The size 150 furnace natural gas only is also approve
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