Finding : Compressor is too cold.
Cause : Possibly flow of liquid refrigerant from evaporator to suction line and compressor.
Action : Set TXV for lower superheat.
Finding : Compressor is too hot.
Cause : Compressor and its motor overloaded because evaporator load.
Action : Reduce evaporator load or replace with larger size compressor.
Cause : Insufficient liquid in evaporator.
Action : Locate fault online between condenser and TXV. See suction pressure is too low.
Cause : Low evaporator load.
Action : Locate fault online between condenser and TXV. See suction pressure is too low.
Cause : Suction and Discharge valve leaking.
Action : Replace it.
Cause : Condensing pressure too high.
Action : Clean condenser and check motor is working or not.
Finding : Compressor cycling (Cut out via HP Control).
Cause : Condenser pressure is too high.
Action : Clean condenser and check motor is working or not.
Cause : HP control is defective.
Action : Replace HP control.
Cause : HP control set too low.
Action : Using pressure gauge set pressure control at value.
Finding : Compressor cycling (Cut out via LP Control)
Cause : Compressor capacity is too high.
Action : Establish capacity regulation.
Cause : Compressor id too large.
Action : Replace with smaller size.
Cause : Opening pressure of evaporative pressure regulator set to high.
Action : Using pressure gauge set at correct value.
Finding : Compressor is running continuously (Suction pressure too high)
Cause : Compressor suction and discharge valve is leaking.
Action : Replace valve.
Cause : Compressor capacity too low at load given time.
Action : Replace compressor.
Finding : Compressor continuously running (Suction pressure too low)
Cause : Cut out of LP is too low or LP defective.
Action : Set pressure or replace it.
Finding : Compressor oil boiling during Operation.
Cause : Flow of liquid refrigerant to compressor.
Action : Set TXV.
Cause : System with oil separator float valve not closing completely.
Action : Replace float valve or oil separator.
Finding : Oil Boiling during start.
Cause : High refrigerant absorption in crankcase because of low ambient.
Action : Install heater element under compressor.
Finding : System with OS: Too much absorption of refrigerant in oil separator during stands till.
Action : Oil separator too cold during start; Install thermostat control heating element or solenoid valve with time delay in oil return tube. Fit NRV in discharge line after oil separator.
Finding: Compressor oil discolored.
Cause : System contamination rising.
Action : Change oil & filter drier.
Cause : Cleanliness does not observe during installation.
Action : Clean out system.
Cause : Moisture contained.
Action : Clean system necessary.
Cause : High discharge pipe temperature.
Action : Locate remedy cause of temperature and clean system necessary.
Cause : Inadequate clean after motor burnout.
Action : Clean refrigerant system. Replace filter several times if necessary.
Finding : Oil level too high.
Cause : Oil Quantity to large.
Action : Drain oil to correct level.
Cause : Refrigerant absorption in crank oil due to low ambient.
Action : Install heating element under compressor.
Finding : Oil level too low.
Cause : Wear on piston ring or cylinder.
Action : Replace worn part.
Cause : Compressor is not in same horizontal plane or equalizing pipe is too small.
Action : Resize the oil equalizing pipe or fix electronic oil management system.
Cause : Float valve partly or fully chocked.
Action : Replace it or clean it.
Finding : Compressor does not start.
Cause : Insufficient electric supply.
Action : Check electricity
Cause : Blown fuse/ MCB
Action : Locate and repair wiring fault/ tripping PCB.
Cause : Main switch OFF.
Action : Switch on
Cause : Fuse in control circuit blown
Action : Locate and repair wiring fault and change fuse
Cause : Thermal protection on motor is defective.
Action : Locate and remedy cause of excessive current consumption. Start system when winding cooled down.
Cause : Supply voltage too low.
Action : Check with electricity.
Cause : Single face drops out.
Action : Locate and remedy fault (often blown fuse).
Cause : Excessive suction pressure.
Action : Motor KVL crankcase pressure regulator.
Cause : Condensing pressure is too high
Action : Clean condenser and check condenser fan motor.
Cause : Short circuit of motor winding (Motor burn out).
Action : Cleanout refrigerant system and replace motor.
Cause : Starting current too high
Action : Locate and remedy of overload, Replace contactor.
Cause : Dirt Particles in refrigerant system.
Action : Cleanout system and install new filter drier and new compressor.
Cause : Copper plating on motion gear because acid formation in refrigerant system.
Action : Cleanout system and install new filter drier and new compressor.
Cause : Contactor Undersized.
Action : Replace contactor with larger size.
Cause : Compressor and motor overloaded.
Action : Locate and remedy cause of overload. Replace compressor.
Cause : Defective oil pump
Action : Replace oil pump
Cause : Oil boiling in crankcase
Action : Use crankcase heater and/ or pump down.
Cause : Flow switch-Insufficient brine concentration/ pump not working, Evaporator temperature too low.
Action : Locate remedy of low or no flow in brine circuit.
Cause : Supply voltage too low.
Action : Contact with Electricity supplier.
Cause : Single phase dropout.
Action : Locate remedy fault.
Cause : Short circuit of motor winding.
Action : Cleanout refrigerant if necessary and replace compressor and filter drier.
Finding : Condensing pressure High
Cause : HP control- Air or other not condensable gases in refrigerant system.
Action : Purge and charge condenser system until reaches running temperature.
Cause : HP control-Condenser surface to small.
Action : Replace condenser with larger size.
Cause : HP control-Refrigerant system charge to large (Liquid connection in condenser)
Action : Recover refrigerant until condensing pressure is normal. Sight glass must be full.
Cause : HP control-Condensing pressure regulation set for too high pressure.
Action : Set to correct pressure.
Cause : HP control-Dirt on condenser surface.
Action : Clean condenser
Cause : HP control-Fan motor or blade defective or too small.
Action : Replace motor or fan blade or both.
Cause : HP control-Air flow to condenser restricted
Action : Remove air inlet obstruction or move condenser.
Cause : HP control-Ambient temperature too high
Action : Create fresh air inlet or move condenser
Cause : HP control-Incorrect air flow direction through condenser.
Action : Change rotation of fan motor. On condensing units, air must flow through condenser and then compressor.
Cause : HP control-short circuit between condenser fan airside pressure and suction sides.
Action : Install a suitable duct, possibly to outdoor air.
Cause : HP control-Cooling water temperature too high.
Action : Ensure lower water temperature.
Cause : HP control-Water quantity too small
Action : Increase water quantity, possibly by using automatic water valve.
Cause : HP control-Deposits on inside of water pipes. (Scale etc.)
Action : Cleanout condenser tubes, possibly by deacidification.
Cause : Water pump defective or not connected.
Action : Investigate cause, replace, or repair cooling water pump if fitted.
Finding : Suction pressure too low
Cause : LP Control-LP set Incorrectly
Action : Adjust or Replace LP control.
Cause : LP Control-Insufficient liquid in evaporator
Action : Locate fault between liquid receiver and suction line
Cause : LP Control-Low evaporator load
Action : Locate fault between liquid receiver and suction line
Cause : LP Control-Leaking suction or discharge valve
Action : Replace compressor valve plate (Semi hermetic) /Compressor (Hermetic).
Cause : Low system load
Action : Establish capacity control or increase low pressure differential
Cause : Insufficient refrigerant in receiver.
Action : Add Refrigerant.
Cause : Liquid line is too long
Action : Shorten line by relocate condenser or receiver/ mount bigger liquid line.
Cause : Liquid line is too small.
Action : Mount bigger liquid line.
Cause : Sharp band in liquid line.
Action : Use band smoother.
Cause : Filter drier Partially blocked.
Action : Replace filter drier.
Cause : Solenoid valve sticking.
Action : Replace or clean solenoid valve.
Cause : Inadequate subcooling.
Action : Add internal Heat exchanger.
Cause : Fault at TXV.
Action : Exchange TXV
Cause : Evaporator too small.
Action : Replace with larger evaporator.
Cause : Evaporator fan defective.
Action : Repair or replace fan.
Cause : Pressure drops in evaporator and/or suction line too long.
Action : If necessary, replace evaporator and/or suction line.
Cause : Lack of or inadequate defrosting of air cooler.
Action : Establish defrost system or adjust defrost procedure.
Cause : Freezing in brine cooler.
Action : Increase brine concentration and check freezing protection equipment
Cause : insufficient air or brine through cooler.
Action : Check fan motor or pump
Cause : Oil collection in evaporator.
Action : Level out and avoid oil traps, Add U traps every 3mtr if suction line going longer distance straight upward.
Finding : Discharge pipe temperature too high.
Action : Replace Valve Plate and/or compressor.
Finding : Discharge line temperature too low.
Cause : Liquid Flow to compressor (TXV superheat set too low, or bulb location is incorrect)
Action : Set superheat higher
Cause : Condensing pressure too low
Action : Wintertime with air cooled condenser fan speed controller must on.
Finding : Knocking Sound.
Cause : Liquid hammer in cylinder because of liquid flow in compressor
Action : Set TXV to higher superheat.
Cause : Oil boils up due to liquid build up in crankcase
Action : Install heater in or under crankcase.
Cause : Wear on moving parts like bearing
Action : Repair or replace compressor.
Finding : Suction gas temperature too High
Cause : System refrigerant charge too small
Action : Charge refrigerant to correct level.
Cause : Defect in liquid line of components in liquid line
Action : Check filter drier block, if blocked then replace it.
Cause : TXV Superheat set too high
Action : Adjust TXV Super heat if valve bulb feels warm by hand.
Finding : Suction gas temperature too low
Cause : TXV Superheat set too low
Action : Set TXV to higher superheat
Cause : TXV Bulb located incorrectly (too warm or poor contact on piping)
Action : Check the bulb location and insulate bulb with rubber foam.
Finding : Suction pressure too high
Cause : Compressor too small.
Action : Replace compressor with larger capacity.
Cause : One or more compressor disk valve leaking.
Action : Replace valve plate or compressor.
Cause : System load too high.
Action : Replace compressor with larger capacity.
Cause : Hot gas defrost valve leaking.
Action : Replace valve.
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