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Service Section Technical Training. Air Conditioning Troubleshooting.

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Presentation on theme: "Service Section Technical Training. Air Conditioning Troubleshooting."— Presentation transcript:

1 Service Section Technical Training

2 Air Conditioning Troubleshooting

3 Air Conditioning System Electrical circuitElectrical circuit Refrigerant circuitRefrigerant circuit An air conditioning system can be divided into 2 main functioning groups

4 Air Conditioning System To troubleshoot a system, one must have to adopt divide and conquer technique Divide the Big problem into multiple smaller problemsDivide the Big problem into multiple smaller problems Solve each of the problem individuallySolve each of the problem individually Put electrical problem in first priorityPut electrical problem in first priority A main point to take note is that if a system do not start, the faulty must be from electrical faultA main point to take note is that if a system do not start, the faulty must be from electrical fault

5 Troubleshooting electrical faults Always ask a lot of questions and do not make assumption before we check Is the power supply being switch on / being connected ?Is the power supply being switch on / being connected ? Is the wiring being done properly?Is the wiring being done properly? Is the wire loose ?Is the wire loose ? Is there any signal coming from controller or thermostat ?Is there any signal coming from controller or thermostat ?

6 Troubleshooting electrical faults 1) Unit will not start Main power supply fail ? Voltage fluctuation ?Main power supply fail ? Voltage fluctuation ? Blown fuse or varistor ?Blown fuse or varistor ? Faulty transformer ?Faulty transformer ? Loose connections ?Loose connections ? Shorted or broken wires ?Shorted or broken wires ? Safety device opens ?Safety device opens ? No signal from thermostat/controller ?No signal from thermostat/controller ? Faulty thermostat ?Faulty thermostat ?

7 Troubleshooting electrical faults 2) Some components do not start Loose connections ?Loose connections ? Shorted or broken wires ?Shorted or broken wires ? No signal from thermostat/controller ?No signal from thermostat/controller ? Faulty magnetic contactor ?Faulty magnetic contactor ?

8 Troubleshooting electrical faults 3) Controller/thermostat A clear understanding of the functional specification of the controller/thermostat is crucial.A clear understanding of the functional specification of the controller/thermostat is crucial. Setting of the controller/thermostat must be obtained.Setting of the controller/thermostat must be obtained. Operating temperatures must be obtained (exp: room, return air, ambient, water, etc.)Operating temperatures must be obtained (exp: room, return air, ambient, water, etc.)

9 Troubleshooting refrigerant faults Some of the major problems found in a air conditioning system The air conditioner runs but shortly stopsThe air conditioner runs but shortly stops The air conditioner short cycles with insufficient coolingThe air conditioner short cycles with insufficient cooling The air conditioner runs continuously with insufficient coolingThe air conditioner runs continuously with insufficient cooling

10 Troubleshooting refrigerant faults Three main conditions in the air conditioners that are operating but not cooling satisfactorily are High discharge pressureHigh discharge pressure Low suction pressureLow suction pressure High suction pressureHigh suction pressure

11 Troubleshooting refrigerant faults 1) High discharge pressure Dirty or partially blocked condenserDirty or partially blocked condenser Air or other non-condensable gases in refrigeration cycleAir or other non-condensable gases in refrigeration cycle Overcharge of refrigerantOvercharge of refrigerant Insufficient condensing mediumInsufficient condensing medium High temperature condensing mediumHigh temperature condensing medium Short cycling of condensing airShort cycling of condensing air

12 Troubleshooting refrigerant faults 2) Low suction pressure Insufficient air or heat load on evaporator coilInsufficient air or heat load on evaporator coil Resistance against refrigerant flowResistance against refrigerant flow Shortage of refrigerantShortage of refrigerant Faulty capillary tube or expansion valveFaulty capillary tube or expansion valve

13 Troubleshooting refrigerant faults 3) High suction pressure Heavy load conditionsHeavy load conditions Unit undersized for applicationUnit undersized for application Low superheat adjustmentLow superheat adjustment Improper expansion valve adjustmentImproper expansion valve adjustment Poor installation of feeler bulbPoor installation of feeler bulb inefficient compressorinefficient compressor

14 Troubleshooting refrigerant faults Some of the problems of refrigerant system can be diagnose through the use of pressure gauge and also an ammeter

15 Troubleshooting electrical faults H.P L.P AMP Both high and low pressure are very high Running current increase extremely Pressure and running current reading Refrigerant overcharged >> Wet operation Main causes of troubles * In case refrigerant overcharged excessively, high pressure switch or overcurrent relay functions

16 Troubleshooting electrical faults H.P L.P AMP Discharge pressure is very high Suction pressure is a little higher than normal Running current increases Pressure and running current reading Insufficient condensing medium Main causes of troubles * Dirty condenser * Partially blocked condenser * Malfunction of condenser fan or fan motor * Reverse revolution of condenser fan * Short cycling of condensing air * High temperature condensing air

17 Troubleshooting electrical faults H.P L.P AMP Discharge pressure is a little higher than normal Suction pressure is very high Running current increases Pressure and running current reading Unit undersized for application Heavy load condition Main causes of troubles * High suction air temperature >> superheated operation Excessive air flow rate Excessively opened expansion valve >> wet operation * Poor installation of feeler bulb * Low superheat adjustment

18 Troubleshooting electrical faults H.P L.P AMP Discharge pressure is a little lower than normal Suction pressure is very low Running current decreases Pressure and running current reading Shortage of refrigerant Restricted refrigerant flow Main causes of troubles * Expansion valve or capillary tube obstructed * Dryer or filter clogged with dirt * Valve in liquid line partially closed * Obstruction in liquid line * Leaking power element on expansion valve * Frost grows on evaporator coil >> superheated operation

19 Troubleshooting electrical faults H.P L.P AMP Discharge pressure is a little lower than normal Suction pressure is very low Running current decreases Pressure and running current reading Insufficient heating medium >> wet operation Main causes of troubles (continue) * Poor evaporating air flow rate - Dirty air filter - Slippage of fan belt - Reverse revolution of evaporator fan - Short cycling of cooling air * Light load condition - Low suction air temperature * Frost grows on evaporator coil

20 Troubleshooting electrical faults H.P L.P AMP Discharge pressure is a little lower than normal Suction pressure is very high Running current decreases Pressure and running current reading Malfunction of compressor >> super heated operation Main causes of troubles

21 Troubleshooting electrical faults H.P L.P AMP Both high and low pressures are very low Running current decreases extremely Pressure and running current reading Extreme refrigerant shortage >> super heated operation Main causes of troubles

22 Liquid refrigerant comes back to the compressor Liquid compression Vane or valve failure Insufficient lubrication (washed out) Refrigerant is dissolved in oil Oil foaming Bearing failure Motor coil insulation is being eroded Motor coil failure Wet operation

23 Suction and discharge gas temperature is higher than the normal Oil temperature becomes higher Carbonization of oil Incomplete seat action Oil viscosity drops Insufficient lubrication Bearing failure Insufficient cooling for motor coil Motor coil failure Super heated operation

24 Thank you


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