LAHK-1 Service Manual
Contents
1. F Ohms _ 86 8056 59 15 714 5 72 906 _ 84 8448 30 34 562 3 77 620 82 8862 55 17 438 28 36601 1 82676 81 9 077 54 17 902 0 85 340 _ 52 18873 26 38 776 2 90 962 _ 50 19 903 23 42 315 4 96 999 48 20 997 21 44 875 6 103 486 46 22 159 19 47610 8 110 460 _ 45 22 767 18 49 047 9 114 141 16 52 069 11 121 921 68 12 493 41 25 394 14 55 301 13 130 295 66 13 139 12 58 759 15 139 313 64 13 822 10 62 460 _ 9 64408 18 154 169 61 14 924 34 30 856 20 165 048 Specifications are subject to change without notice 3 Circuit Board Confirm the thermistor is operating properly before troubleshooting the circuit board Make sure the control board has 24 Volts AC when measured at the 24 VAC and the com terminals If not find the cause of voltage failure The circuit board is designed to convert the thermistor ohm input to a 2 9 16 VDC output to control the position of the damper actuator Above 2 VDC output the actuator will start to move the damper toward the closed position At 9 16 VDC the actuator will have moved 85 degrees and the damper will be approximately 95 closed The damper should never be 100 closed The chart below includes the various damper angles based on the different outdoor temperatures Measure2. Outdoor Unit Control Board 10K ohm thermistor r r l l f i v common blk TE black D Low Ambient Hood 4 na E Part Number LAHK 1 I 208v or m Insert the black plug into the CNAC2 connection Su pply Voltage 208 230V 1 phase 60Hz E on the board Connect the white wire male F l connector to the wire that corresponds to the Am ps 0 20 i outdoor unit supply voltage as shown below i move and secure cap to unused wire Fuse Size 1 amp 208 volt orange wire female connector LL 20460 Volt white wire female connector _ i CRIBUE Carei For use with Modular PURY and PUHY outdoor units To reversing valve 21S4a T Y S KMU amp T Y S LMU Series Only yellow Serial Number Date of Manufacture CN505 PNW PW OD Initials Disconnect white plug with four wires from the CN505 connection Plug the white male connector from the low ambient kit onto green the CN505 connection Connect the white Manufactured for Mitsubishi Electric US Inc L plug with four wires onto the spare connection l Specifications are subject to change without notice 2015 Mitsubishi Electric US Inc 10 2015 Mitsubishi Electric US Inc Specifications are subject to change without notice 11 This product is designed and intended for use in the commercial environment Please be sure to put the contact address telephone number on this manual before handing it to the customer Manufactured for MITSUBISHI ELECTRIC US INC 1340
3. Satellite Boulevard Suwanee GA 30024 Toll Free 800 433 4822 www mehvac com CITYMULTI Low Ambient Hood LAHK 1 Technical amp Service May 2015 Specifications are subject to change without notice 2015 Mitsubishi Electric US Inc
4. on the stop are engaged into the actuator motor teeth 1 Loosen the Philips head screw for the mechanical stop 4 Using the crank handle turn the motor counterclockwise until the 3 Loosen the 2 nuts on the damper shaft U clamp indicator snugs against the stop at 85 degrees 24VAC DC 50 6 32 8 RAJAS edo A D a FEH 23 x za SOJ sfa e gt e 7 P zs 3s zio a EO a a 8352S st xy 7 a o s Z x w a gt S Sg oi S S N ae K oO lt i NIE T 2 s Sa z s NE N Jea 2925 3 Ose Wisin 22506 Ws Miz sae mea s gis 3 Ws i E miz amp Asa 6 Close the blades by hand and insert Crank handle under damper blade near the screws as shown to ensure it is open approximately 1 4 inch at 85 degrees Specifications are subject to change without notice 2015 Mitsubishi Electric US Inc 6 7 Holding the blades against the handle re tighten the 2 nuts on Ensure end of shaft is flush to edge of clamp black surface as shown the damper shaft U clamp 8 Slightly crank the handle to release the motor The damper will return to the open position Review and Manual Test To ensure the LAHK unit is functioning as designed Crank the Belimo motor back to the 85 degree position and visually check that the damper does not close completely Your goal is approximately 1 4 opening between the blades at the 85 degree position 2015 Mi
5. will close to a position equal to that required during the cooling cycle Once the unit comes back out of defrost and into heating mode the damper will again spring wide open for full airflow Operation Test Outdoor unit must be in cooling mode All hoods and damper controls are tested at the factory before shipping To perform an operational test once the installation has been completed follow the steps below Operation testing when the outdoor ambient is ABOVE 50 F 1 Turn on power to the outdoor unit 2 Make sure the outdoor unit is in cooling mode 3 Locate the outdoor temperature sensing thermistor at the end of the short conduit coming out the side of the control panel it can be seen inside the plastic shield 4 Using an aerosol dusting sprayer invert the can and spray the thermistor with very short bursts of the cold liquid Caution Do Not overspray the thermistor as it could be damaged It may take 10 20 seconds for the internal thermistor temperature to drop The damper will start to move toward the closed position after the thermistor drops below 50 F 5 Once the thermistor warms above 50 F it will move back to the full open position indicating the low ambient kit is working as designed Operation testing when the outdoor ambient is BELOW 50 F Turn on power to the outdoor unit 2 Make sure the outdoor unit is in cooling mode 3 The damper will move toward the closed position to a predetermi
6. MANUFACTURED FOR 2015 MITSUBISHI ELECTRIC US INC TECHNICAL amp SERVICE MANUAL wa LAHK 1 Low Ambient Hood for use with CITY MULTI PUHY P T Y S K LMU PURY P T Y S K LMU and PURY HP T Y S KMU Series Outdoor Units Contents 1 Control Box Component Identification cccecceceeeeeeeeeees 2 2 Operating SEQUENCE cccccceeeccceseeeceeeeeceeeeceueeesaeessaaeess 3 3 Damper Blade Adjustment ccsccsssseesssseesesseeseseeeseaeees 5 4 Damper Actuator Manual Override ccccceeceeeeeeeeeeeeeees 8 PAE eiaa cee ne oe ee eee eee 9 6 Wiring ACI AMM caivesuicatnureinadoisnanre snahorsiawssiancidaiel melaieaatsapainadoins 10 1 Control Box Component Identification DAMPER CONTROL BOX CONTROL BOARD TRANSFORMER 208 230 24VAC 40VA INTERLOCK RELAY SPDT 240 VOLT COIL TERMINAL BLOCK DAMPER ACTUATOR ee j a THERMISTOR WITH PLASTIC SHIELD Specifications are subject to change without notice 2015 Mitsubishi Electric US Inc 2 2 Operating Sequence Outdoor Unit in Cooling Mode The LAHK 1 low ambient hood is designed to reduce the airflow through the outdoor units as the ambient temperature drops This maintains the head pressure at a level that will allow the system to perform at 100 capacity down to 100F outdoor temperature A thermistor mounted on the side of the unit senses the outdoor temperature As the outdoor temperature drops the resistan
7. ble that during shipping the damper shaft may have mechanical stop to adjust the maximum angle of rotation This must moved in the actuator shaft clamp assembly In some cases due be adjusted to 85 degrees and the damper blade position verified or to manufacturing tolerances the LAHK blades could close 100 re set to the proper position 1 4 open to ensure the unit functions The damper should never be 100 closed during operation properly When working properly the damper will be approximately 95 closed at 20 and below The following procedure will allow proper adjustment Belimo motor angle indicating The factory setting for the mechanical stop scale shown below is shown below at 95 Angle Indicator IMPORTANT ENSURE POWER IS OFF BEFORE STARTING Basic Service Overview 1 Set damper motor stop to 85 degrees 2 Loosen U bolts on damper shaft 3 Crank motor against 85 stop then lock into position 4 Set damper to approx open Use damper crank handle as spacer Re Tighten U bolts on damper shaft Release motor by slightly cranking with handle Check operation manually 7 The goal is to have opening on damper assembly in the 85 degree position oe 2015 Mitsubishi Electric US Inc Specifications are subject to change without notice 5 STEP BY STEP INSTRUCTIONS 2 Slide the mechanical stop to 85 halfway between 8 and 9 and tighten the screw making sure the locating teeth
8. ce of the thermistor increases The thermistor is connected to the specially designed circuit board and the resistance value from the thermistor is converted to a DC voltage output within the circuit board This DC voltage output drives the damper actuator to a predetermined position based on the outdoor temperature The inverter driven fan motor will adjust the discharge pressure based on system capacity demand The motor will speed up and force more air through the damper if there is a higher system capacity demand or slow down if system capacity demand decreases Outdoor Unit in Heating Mode Heating mode requires the damper be in the fully open position to allow full airflow and maximum heating capacity Heating mode automatically deactivates the kit through an interlock relay The coil for this relay is tied into the reversing valve connection on the outdoor unit When the unit switches to heating mode the reversing valve is energized This in turn energizes the interlock relay When the relay is energized the normally closed contact opens By opening this contact the power to the transformer and control board is interrupted this allows the damper to spring to the full open position Outdoor Unit in Defrost Mode If the outdoor unit will be running in heating mode a defrost period is inevitable During defrost the low ambient controls see this as the unit operating in cooling mode If the outdoor temperature is below 50 F the damper
9. he Unlocking the damper actuator damper actuator 2 options Flip the lock switch to the position pointing to Flip the lock switch to the locked symbol the position pointing to the unlocked symbol Remote control by supplying power to the unit for gt than 3 sec Angle Indicator 2015 Mitsubishi Electric US Inc 5 Parts List Damper Control Box Part Description Damper Actuator Part Number NFB24 SR Interlock Relay 240 volt coil Transformer 208 230 24vac 40VA R68AA0005 R68A B0006 Circuit Board CB LAHK 1 A Themistor hamess assy TH LAHK 1 A CN505 Connector CNAC2 Connector HC LAHK 1 1A HC LAHK 1 2A A o ere Wire Harness Components CN505 Connector Part Number HC LAHK 1 1A Inches everything shown NN AN A ed Red y CNAC2 Connector Part Number HC LAHK 1 2A Inches everything shown Note Damper linkage parts can be purchased locally If damper blades or complete assembly needs replacing order new LAHK 2 hood and damper assembly 2015 Mitsubishi Electric US Inc Specifications are subject to change without notice 9 6 Wiring Diagram LAHK 1 Wiring Diagram Control Box Mounted on Hood 40 VA Transformer Damper Actuator Common 24 V Hot i 2 10VDC Circuit Board 240 volt ac NC Relay W Terminal strip Factory switch positions
10. lt units the CNAC2 connector will also provide 230 volts to the control transformer Once the proper connection is confirmed measure voltage on the primary side of the transformer It should be 208 or 230 10 depending on the supply voltage at the outdoor unit If there is no voltage on the primary side of the transformer check the fuse that is located in the fuse holder inside the outdoor unit See wiring diagram for fuse location Once power has been confirmed at the primary side of the transformer check the secondary low voltage side of the transformer it should be approximately 27 volts If no voltage is present replace transformer Specifications are subject to change without notice 4 Interlock Relay The interlock relay uses a normally closed contact to allow power to flow to the transformer energizing the low ambient kit control circuitry Any time the outdoor unit is in cooling mode this contact will be in closed When the outdoor unit reversing valves energizes switches to heating mode the coil of the relay is energized opening this contact This in turn de energizes the transformer disconnecting power to the low ambient kit control circuitry This allows the damper to spring return to the full open position during heating mode To check make sure the contact is closed when the outdoor unit is in cooling mode coil de energized and the contact is open when the outdoor unit is in the heating mode coil energized Dam
11. ned position based on the outdoor ambient temperature indicating the low ambient kit is working as designed 2015 Mitsubishi Electric US Inc If neither of these tests work Proceed with the component troubleshooting instructions Component Troubleshooting Thermistor The thermistor is a 10 000 Q NTC Type The circuit board has a blinking indicator light built in to reference what the thermistor is sensing The chart below shows what the blinking light sequence means Blink s Thermistor Temperature Above 50F 50F to 20F HMM 3 Below 20F Constant ON Thermistor is open or shorted If the light is on constantly the thermistor is open or shorted and needs to be replaced If the blinking light sequence doesn t fall within the range given in the chart the thermistor needs to be replaced If its Suspected that the thermistor is operating inaccurately check the tolerance in the following instructions Disconnect the thermistor from the control board Measure the resistance across the two leads Measure the temperature of the thermistor Accuracy on the temperature reading is important to prevent a good thermistor from being replaced Compare the ohm reading with the temperature on the chart below Based on the thermistor temperature the ohm reading should be within 1 2 of the number shown below If not and the thermistor connections are not corroded the thermistor should be replaced F Ohms er Ohms F Ohms
12. per Actuator Before trouble shooting the damper motor verify the two factory switches are in the position shown below Damper Actuator 1 Common 2 Hot 3 2 10VDC 5 Factory switch positions Make sure the motor has 24 volts on the 1 Common and 2 Hot connections If not find the cause of the voltage failure and correct The damper actuator receives a DC voltage signal from the circuit board This voltage can be measured between 1 Common and 3 2 10VDC connections The damper actuator has an angle indicator where it clamps onto the damper shaft linkage Compare the DC voltage supply to the damper angle indicator position in the chart below The angle should be within 2 of the chart shown below If not check to make sure the damper started off in the correct position 0 Degrees IMPORTANT It s possible that during shipping the damper shaft may have moved in the actuator shaft clamp assembly See Section 3 Damper Blade Adjustment If the damper actuator angle doesn t match within 2 with the corresponding control board voltage supplied as shown below the damper actuator should be replaced Temperature Ohms DC volts output Angle p82 wen 20 pO f ago 8H p45 rer 402608 80s s 30000 o a o a9 is o wo 3046200 l oe 2015 Mitsubishi Electric US Inc 3 Damper Blade Adjustment IMPORTANT The Belimo damper motor within the LAHK control box has a built in It s possi
13. the DC voltage output on the circuit board at com and the out terminals If the output doesn t match the thermistor input ohms as shown below replace the circuit board ETEN m DC volts MN ETE Above52 F 52 F 2 2 00 a O DE 50 f 19903 825 p45 ro 450 a ofulopen _ full open o a ta BOT p85 sooo za o 3 o aae 790 o 5 ssar ems e 2 4220 oie a Transformer The transformer is 208 230 24volt AC For proper connections to the outdoor unit the following diagram and instructions should be referred to Outdoor Unit Control Board j CNAC2 Connection common blk 230 460v wh i g mm m q a the black plug into the CNAC2 connection i on the board Connect the white wire male connector to the wire that corresponds to the outdoor unit supply voltage as shown below move and secure cap to unused wire 208v or 208 volt orange wire female connector 230 460 volt white wire female connector oe am am am am so od The low ambient kit is designed to function with both 208 230 volt and also 460 volt outdoor units On 208 volt units the CNAC2 connector will provide 208 volts to the control transformer On 230 volt units the CNAC2 connector will provide 230 volts to the control transformer The 460 volt units include a transformer that reduces the outdoor unit internal voltage to 230 volts Because of this on the 460 vo
14. tsubishi Electric US Inc Specifications are subject to change without notice 7 4 Damper Actuator Manual Override IMPORTANT Never manually override the damper position if the outdoor unit could switch to heating mode during the override period Heating mode requires the damper to be fully open for full capacity It may be desirable to manually override the damper position and lock it into position until repairs can be completed If so select an average temperature typical for the outside environment during the override period and then use that average temperature to find the desired damper angle in the chart below Temperature Ohms DC volts output Angle ps2 aena 20 pO 19 9038 35 tS 39917 875 46220 916 Below 20 F Oo 5 w a ae a oo o 3w sase 790 Oo 35 20 Follow the instructions below for manually positioning and locking the damper in place IMPORTANT Disconnect power to the damper motor before locking in place The damper actuator comes with a crank handle attached to manually move the damper position The crank handle is removable and if it s missing a 3 16 allen wrench will work just as well Use the following diagrams and instructions for this procedure Specifications are subject to change without notice 8 Winding the damper actuator insert crank handle tum handle in direction of arrow 1 f SS Z he Locking t
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