Carrier 38mvc018 3 Service Manual
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31 CHART 3 -- COMPRESSOR OVERCURRENT PROTECTION Is unit running in outdoor ambient higher than 125 °F?Beyond operating range Outdoor coil clean?Clean coil. Problem persists?Problem solved Check connections from OD board. Corrosion, or high resistance Outdoor fan Ok? Connect gauges to unit. pressures ok? Check amp draw to compressor? Values within range? Replace outdoor board Replace compressorClean/repair connection Problem persists?Problem solved Change outdoor motor High head, high suction? High head, low suction? Unit is overcharged. Reclaim charge and weigh in correct charge. Yes Yes Yes Yes Yes NoNo No No No No NoYes YesNo No Yes Yes Restriction in refrigeration circuit. Is unit running in outdoor ambient higher than 125 °F?Beyond operating range Outdoor coil clean?Clean coil. Problem persists?Problem solved Check connections from OD board. Corrosion, or high resistance Outdoor fan Ok? Connect gauges to unit. pressures ok? Check amp draw to compressor? Values within range? Replace outdoor board Replace compressorClean/repair connection Problem persists?Problem solved Change outdoor motor High head, high suction? High head, low suction? Unit is overcharged. Reclaim charge and weigh in correct charge. Yes Yes Yes Yes Yes NoNo No No No No NoYes YesNo No Yes Yes Restriction in refrigeration circuit. A08168 38/40MVC, MVQ
32 CHART 4 -- INDOOR UNIT COMMUNICATION ERROR SIZE 9K AND 12K Reset main power and restart system using remote. Problem persists? . No further action is required No Yes Measure Volts DC on outdoor TB between 1 & 3. Ok?** Yes Check the wires and connections between Indoor and outdoor units* No Fix connection or replace wiring No Yes Replace outdoor board. ** There is a 2 to 3 minute window to take the measurement before the diagnostic light is on again.Measure Volts DC on indoor TB between 1 & 3. Ok?** No Replace indoor board.Recheck wiring and connections Notes: Before measuring the Volts DC on outdoor TB, disconnect the field wire on terminal 1. Before measuring the Volts DC on Indoor TB, disconnect the field wire on terminal 1. Have the red probe of the meter on terminal 1 and the black probe on terminal 3. Reconnect wiring when measurements are complete. Reset main power and restart system using remote. Problem persists? . No further action is required No Yes Measure Volts DC on outdoor TB between 1 & 3. Ok?** Yes Check the wires and connections between Indoor and outdoor units* No Fix connection or replace wiring No Yes Replace outdoor board. * Make sure wires are connected per connection diagrams. Failing to do that will result in a communication error. ** There is a 2 to 3 minute window to take the measurement before the diagnostic light is on again.Measure Volts DC on indoor TB between 1 & 3. Ok?** No Replace indoor board.Recheck wiring and connections Notes: Before measuring the Volts DC on outdoor TB, disconnect the field wire on terminal 1. Before measuring the Volts DC on Indoor TB, A08181 38/40MVC, MVQ
33 CHART 5 -- OUTDOOR UNIT PROTECTS Suction and head equal? Outdoor coil clean?Clean coil. Problem persists? Check sensors. Flow Chart #2 Connect gauges to unit. Pressures ok? Check compressorNormal suction, high head? Non condensables in sys. Pump down and recharge unit High head, high suction? Unit is overcharged. Reclaim charge and weigh in correct charge High head, low suction? Yes No No No No Problem solved No No Yes Yes Yes Yes Yes Yes Yes Check application limits Check outdoor unit board. Indicator light flashing twice? No See note below* * Restriction in system. Check capillary tube, check for moisture, and check for damage to liquid line between indoor and outdoor units. Suction and head equal? Outdoor coil clean?Clean coil. Problem persists? Check sensors. Flow Chart #2 Connect gauges to unit. Pressures ok? Check compressorNormal suction, high head? Non condensables in sys. Pump down and recharge unit High head, high suction? Unit is overcharged. Reclaim charge and weigh in correct charge High head, low suction? Yes No No No No Problem solved No No Yes Yes Yes Yes Yes Yes Yes Check application limits Check outdoor unit board. Indicator light flashing twice? No See note below* * Restriction in system. Check capillary tube, check for moisture, and check for damage to liquid line between indoor and outdoor units. A08182 38/40MVC, MVQ
34 CHART 6 -- INDOOR UNIT COMMUNICATION ERROR SIZE 18K AND 24K * Make sure wires are connected per connection diagrams i.e. L1 to L1 and L2 to L2. Failing to do that will result in a communication error. ** There is a 2 to 3 minute window to take measurements before the diagnostic light is on again. Reset main power and restart system using remote. Problem persists? . No further action is required No Yes Measure VDC reading on outdoor between S and G. Reading positive? ** Yes Check the wires and connections between Indoor and outdoor units* No Fix connection or replace wiring Yes NoReplace outdoor board Replace indoor board.Notes: When unit is operating normally and a DC voltage reading is taken between the S and G terminal on the outdoor unit (or indoor unit) positive and negative readings will fluctuate between 0 and 24V DC. If indoor board is bad, only a positive readings will be registered between terminals S and G on the outdoor unit. The reverse will apply if outdoor board is bad (only negative readings will register). Above data is obtained by having the red probe of the meter on the S terminal and the black probe on the G terminal. * Make sure wires are connected per connection diagrams i.e. L1 to L1 and L2 to L2. Failing to do that will result in a communication error. ** There is a 2 to 3 minute window to take measurements before the diagnostic light is on again. Reset main power and restart system using remote. Problem persists? . No further action is required No Yes Measure VDC reading on outdoor between S and G. Reading positive? ** Yes Check the wires and connections between Indoor and outdoor units* No Fix connection or replace wiring Yes NoReplace outdoor board Replace indoor board.Notes: When unit is operating normally and a DC voltage reading is taken between the S and G terminal on the outdoor unit (or indoor unit) positive and negative readings will fluctuate between 0 and 24V DC. If indoor board is bad, only a positive readings will be registered between terminals S and G on the outdoor unit. The reverse will apply if outdoor board is bad (only negative readings will register). Above data is obtained by having the red probe of the meter on the S terminal and the black probe on the G terminal. Reset main power and restart system using remote. Problem persists? . No further action is required No Yes Measure VDC reading on outdoor between S and G. Reading positive? ** Yes Check the wires and connections between Indoor and outdoor units* No Fix connection or replace wiring Yes NoReplace outdoor board Replace indoor board.Notes: When unit is operating normally and a DC voltage reading is taken between the S and G terminal on the outdoor unit (or indoor unit) positive and negative readings will fluctuate between 0 and 24V DC. If indoor board is bad, only a positive readings will be registered between terminals S and G on the outdoor unit. The reverse will apply if outdoor board is bad (only negative readings will register). Above data is obtained by having the red probe of the meter on the S terminal and the black probe on the G terminal. A08183 38/40MVC, MVQ
35 CHART 7 -- UNIT NOT RUNNING, NO DIAGNOSTIC CODE Yes Use auto forced function. Unit runs? Reset remote and restart the unit. Is unit running? Problem solved Check batteries. OK? Replace battery Go to chart #13 Reset circuit breaker. Is unit running? Yes Problem solvedIs there power to outdoor unit? Yes Check fuse on outdoor board. Ok? Yes Check input and output on outdoor board. Ok? Check components. Ok? Flow charts 10 thru 12 Yes No Replace defective componentCheck wiring and circuit breaker and fix Replace fuse Replace outdoor board Check fuse(s) on indoor board. Ok?* Replace fuse Replace indoor board Check input and output on indoor board. Ok? Determine defective component and replace Yes Yes Yes Yes No No No No NoNo No No No * For sizes 18 and 24 K units only. For sizes 9 and 12K units proceed to check inputs and outputs on indoor boards. Yes Use auto forced function. Unit runs? Reset remote and restart the unit. Is unit running? Problem solved Check batteries. OK? Replace battery Reset circuit breaker. Is unit running? Yes Problem solvedIs there power to outdoor unit? Yes Check fuse on outdoor board. Ok? Yes Check input and output on outdoor board. Ok? Check components. Ok? Flow charts 10 thru 12 Yes No Replace defective componentCheck wiring and circuit breaker and fix Replace fuse Replace outdoor board Check fuse(s) on indoor board. Ok?* Replace fuse Replace indoor board Check input and output on indoor board. Ok? Determine defective component and replace Yes Yes Yes Yes No No No No NoNo No No No * For sizes 18 and 24 K units only. For sizes 9 and 12K units proceed to check inputs and outputs on indoor boards. A08169 38/40MVC, MVQ
36 CHART 8 -- UNIT NOT RUNNING OPTIMALLY Suction and head equal? Outdoor coil clean?Clean coil. Problem persists? Indoor filter clean?Clean filter. Problem persists? Check indoor fan motor Connect gauges to unit. Pressures ok?Replace indoor fan motor. Check compressorNormal suction, high head? High head, high suction? Unit is overcharged. Reclaim charge and weigh in correct charge High head, low suction? Yes Yes Yes No No No No Problem solved Problem solved No No No No No Yes Yes Yes Yes Yes Yes Yes Check application limits. Non condensables in sys. Pump down and recharge unit See note below* * Restriction in system. Check capillary tube, check for moisture, and check for damage to liquid line between indoor and outdoor units. Suction and head equal? Outdoor coil clean?Clean coil. Problem persists? Indoor filter clean?Clean filter. Problem persists? Check indoor fan motor Connect gauges to unit. Pressures ok?Replace indoor fan motor. Check compressorNormal suction, high head? High head, high suction? Unit is overcharged. Reclaim charge and weigh in correct charge High head, low suction? Yes Yes Yes No No No No Problem solved Problem solved No No No No No Yes Yes Yes Yes Yes Yes Yes Check application limits. Non condensables in sys. Pump down and recharge unit See note below* * Restriction in system. Check capillary tube, check for moisture, and check for damage to liquid line between indoor and outdoor units. A08170 38/40MVC, MVQ
37 CHART 9 -- UNIT NOT RUNNING OPTIMALLY (HP IN HEATING)* Visually check outdoor Unit for ice blockage. **Check reversing valve. Go to flow chart #12 No Yes Yes Check defrost sensor. Ok?No Replace sensor Check application limits. Ok? ** Check for blockage on outdoor coil and drain pan. Are the holes in drain pans blocked? NoBeyond operating range Yes Yes Check ambient conditions. Prime icing? Explain to customer Visually check outdoor Unit for ice blockage. **Check reversing valve.No Yes Yes Check defrost sensor. Ok? Go to flow chart #2 No Replace sensor Check application limits. Ok? * To supplement flow chart #8 es in drain pans blocked? NoBeyond operating range Yes Yes Check ambient conditions. Prime icing? Explain to customer A08184 38/40MVC, MVQ
38 CHART 10 -- COMPRESSOR Check contactor output on outdoor board if not done already. If bad, replace outdoor board. * For size 9 and 12k units contactor is on outdoor board. Trace connections from OD board. Connections ok? Check compressor windings. Ok?No fix connection No Yes Check capacitor. Capacitor ok? Yes Check contactor.* Contactor ok? NoReplace contactor Yes NoReplace capacitor NoReplace compressor No Compressor ok. Trace connections from OD board. Connections ok? Check compressor windings. Ok?No fix connection No Yes Check capacitor. Capacitor ok? Yes Check contactor.* Contactor ok? NoReplace contactor Yes NoReplace capacitor NoReplace compressor No Compressor ok. A08171 38/40MVC, MVQ
39 CHART 11 -- OUTDOOR MOTOR Trace connections from OD board. Connections ok? Motor ok. Fix connectionNo YesYes No Replace capacitors YesNo Replace motor Check capacitor. Capacitor ok? Check motor windings. Ok? Visually confirm that fan blades and outdoor coil are not blocked. Clear blockage Yes No Trace connections from OD board. Connections ok? Motor ok. Fix connectionNo YesYes No Replace capacitors YesNo Replace motor Check capacitor. Capacitor ok? Check motor windings. Ok? Visually confirm that fan blades and outdoor coil are not blocked. Clear blockage Yes No A08172 38/40MVC, MVQ
40 CHART 12 -- REVERSING VALVE Check RV connection on outdoor board. Ok? Clean or repair the connectionNo Yes Yes Check RV output on outdoor board. Ok? No Replace outdoor board Replace reversing valve. Yes Check RV solenoid. Ok? Replace solenoid No Check RV connection on outdoor board. Ok? Clean or repair the connectionNo Yes Yes Check RV output on outdoor board. Ok? No Replace outdoor board Replace reversing valve. Yes Check RV solenoid. Ok? Replace solenoid No CHART 13 -- RECEIVER BOARD Check wiring and connection between receiver and ID board. Ok? Fix wiring or connectionNo Yes Replace remote control Yes Check input and output on ID and receiver boards. Ok? No Replace receiver board Check wiring and connection between receiver and ID board. Ok? Fix wiring or connectionNo Yes Replace remote control Yes Check input and output on ID and receiver boards. Ok? No Replace receiver board A08173 38/40MVC, MVQ