Carrier 48MPD Troubleshooting and Diagnostics, Problem Solution Compressor does not RUN, Dsio

Page 56

TROUBLESHOOTING AND DIAGNOSTICS

 

 

 

 

 

 

 

 

PROBLEM

 

SOLUTION

COMPRESSOR DOES NOT RUN

 

 

 

 

 

Contactor Open

 

 

 

1.

Power off.

 

1.

Restore power.

 

 

 

2. Fuses blown in ®eld power circuit.

2.

After ®nding cause and correcting, replace with correct size fuse.

3.

Alarm tripped.

3.

Check alarm history on HSIO.

 

 

 

4. No control power.

4.

Check secondary fuse(s); replace with correct type and size. Re-

5.

Compressor circuit breaker tripped.

 

place transformer if primary windings receiving power.

5.

Check for excessive compressor current draw. Reset breaker; re-

6.

Safety device lockout circuit active.

 

place if defective.

6.

Reset lockout circuit at HSIO or circuit breaker.

 

 

 

7. Low-pressure switch open.

7.

Check for refrigerant undercharge, obstruction of indoor air¯ow, or

 

 

 

 

 

 

 

 

 

 

 

 

whether compressor suction shutoff valve is fully open. Make sure

 

 

 

8. High-pressure switch open.

 

liquid line solenoid valve(s) is open.

 

 

 

8.

Check for refrigerant overcharge, obstruction of outdoor air¯ow, air in

 

 

 

 

 

 

 

 

 

 

 

 

system or whether compressor discharge valve is fully open. Be sure

9.

Loose electrical connections.

 

outdoor fans are operating correctly.

9.

Tighten all connections.

 

 

10. Compressor stuck.

10.

See 06E compressor service literature.

 

 

Contactor Closed

 

 

 

1.

Compressor leads loose.

1.

Check connections.

2.

Motor windings open.

2.

See 06E compressor service literature.

3.

Single phasing.

3.

Check for blown fuse. Check for loose connection at

 

 

 

 

 

 

 

 

 

 

 

 

compressor terminal.

COMPRESSOR STOPS ON HIGH-PRESSURE SWITCH

 

 

 

 

 

Outdoor Fan On

 

 

 

1.

High-pressure switch faulty.

1.

Replace switch.

2.

Air¯ow restricted.

2.

Remove obstruction.

3.

Air recirculating.

3.

Clear air¯ow area.

4.

Noncondensables in system.

4.

Purge and recharge as required.

5.

Refrigerant overcharge.

5.

Purge as required.

6.

Line voltage incorrect.

6.

Consult power company.

7.

Refrigerant system restrictions.

7.

Check or replace ®lter drier, expansion valve, etc. Check that com-

 

 

 

 

 

 

 

 

 

 

 

 

pressor discharge valve is fully open.

 

 

Outdoor Fan Off

 

 

 

1.

Fan slips on shaft.

1.

Tighten fan hub setscrews.

2.

Motor not running.

2.

Check power and capacitor.

3.

Motor bearings stuck.

3.

Replace bearings.

4.

Motor overload open.

4.

Check overload rating. Check for fan blade obstruction.

5.

Motor burned out.

5.

Replace motor.

COMPRESSOR CYCLES ON LOW-PRESSURE SWITCH

 

 

 

 

Indoor-Air Fan Running

 

 

 

1.

Filter drier plugged.

1.

Replace ®lter drier.

2.

Expansion valve power head defective.

2.

Replace power head.

3.

Low refrigerant charge.

3.

Add charge. Check low-pressure switch setting.

 

 

Air¯ow Restricted

 

 

 

1.

Coil iced up.

 

1.

Check refrigerant charge.

2.

Coil dirty.

2.

Clean coil ®ns.

3.

Air ®lters dirty.

3.

Clean or replace ®lters.

4.

Dampers closed.

4.

Check damper operation and position.

 

 

Indoor-Air Fan Stopped

 

 

 

1.

Electrical connections loose.

1.

Tighten all connections.

2.

Fan relay defective.

2.

Replace relay.

3.

Motor overload open.

3.

Power supply.

4.

Motor defective.

4.

Replace motor.

5.

Fan belt broken or slipping.

5.

Replace or tighten belt.

 

 

 

 

LEGEND

 

 

HSIO Ð Human Sensory Input/Output Device

 

 

DSIO

Ð Processor Module

 

 

VFD

Ð Variable Frequency Drive

 

 

56

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Contents Installation, Start-Up and Service Instructions ContentsGeneral ContentsSafety Considerations Installation Install Outdoor HoodsPhysical Data Base Unit 48/50MPPhysical Data Optional Power Exhaust Specications Compressor Oil ChargeVariable Frequency Drive VFD Physical Data FAN MotorRoof Curb Dimensions, 48/50MP62L and 70M Roof Curb Dimensions, 48/50MP82N-10R Base Unit Dimensions, 48MP62L, 70M Base Unit Dimensions, 48MP82N-10R Base Unit Dimensions, 50MP62L and 70M Base Unit Dimensions, 50MP82N-10R Unit Unit WeightSize Field Electrical Connections Make Electrical ConnectionsNEC EquipGND Electrical Data FLALRA MCARecommended Sensor Device Non-Shielded Cable ManufacturerSpace Temperature Sensor Wiring Space Temperature Sensor Averaging Heat Interlock Relay Outdoor Air¯ow Control Transducer/Thermistor CCN Connection Approved Shielded Cables Comm CCNCOM Auxiliary Control Box Location 50MP70M Unit Shown Installing Flue/Inlet Hoods 48MP Units Only Gas Piping DetailsCheck Compressor Mounting Flue De¯ector Baffle AssembledPRE-START-UP System CheckEvaporator-Fan Belts, Pulleys, and Sheaves Ð ExampleFan Performance Forward Curved Ð 48/50MP62L Fan Performance Forward Curved Ð 48/50MP70MFan Performance Forward Curved Ð 48/50MP82N Fan Performance Forward Curved Ð 48/50MP90PFan Performance Forward Curved Ð 48/50MP10R Fan Performance Air Foil Ð 48/50MP62LFan Performance Air Foil Ð 48/50MP70M Fan Performance Air Foil Ð 48/50MP82NFan Performance Air Foil Ð 48/50MP90P Fan Performance Air Foil Ð 48/50MP10RControls Conguration and Quick Test Keypad and Display Module Hsio Configuration Hsio Keypad Key UsageSet Point Ranges and Defaults SET Point Subfunction Display Default Range START-UPInitial Check Basic Conguration DataOccupied Cooling GeneralSupply FAN IGC Control Board LED Alarms OverridesControl Loop Checkout 48/50MP Units SMG, SCV and MLG Recommended Starting ValuesControl System ComponentsIndex of Lead/Lag Circuits Compressors Lead CircuitKeypad and Display Module Hsio Stby YESFunction Hsio Keypad and Display Module Functions and SubfunctionsSUB Functions Service Variable Frequency Drive VFD DisplayPower Exhaust MOTORS, PULLEYS, and Belts EVAPORATOR-FAN MOTORS, PULLEYS, and BeltsManufacturer Lubricant LubricationRefrigerant Circuit Charging Chart Ð Unit 48/50MP62L Charging Chart Unit 48/50MP90P Adjustments Pressure Switch Settings Psig kPagBelt Installation and Tensioning Switch Cutout CUT-IN06E Compressors, Typical Gas Valve Adjustment Protective DevicesMain Burner Removal Compressor ProtectionVariable Frequency Drive VFD Stby no Processor Modules PsioHigh-Voltage Relay Modules DSIO1 and DSIO2 Torque Compressors Compressor Replacement Ð Perform the followingTroubleshooting Troubleshooting and Diagnostics Problem Solution Compressor does not RUNCompressor Stops on HIGH-PRESSURE Switch Compressor Cycles on LOW-PRESSURE SwitchTroubleshooting and Diagnostics IGC Control Heating Ð 48MP Units Only Page Packaged Service Training Call for Free CatalogSTART-UP Checklist Model no Serial no Date TechnicianIII. Preliminary Checklist Items IV. START-UPCL-3 Fact Config Fanm

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