maintenance
Maintenance procedures
WARNING
Hazardous voltage!
Disconnect all electric power, including remote disconnects before servicing. Follow proper lockout/tagout procedures to ensure the power can not be inadvertently energized. Failure to disconnect power before servicing could result in death or serious injury.
Problem
Insufficient cooling
Possible cause
1.Insufficient air flow due to: a) dirty evaporator; b) ice on evaporator coils (indicates airflow restriction through evaporator); c) dirty filter; d) obstructed discharge air intake; e) fan motor not running; f) evaporator fan or fan wheel slipping on motor shaft
2.Heat gain or loss in room exceeds unit capacity
3.Defective compressor
4.Insufficient refrigerant charge indicated by: a) low wattage; b) condenser air outlet
cold
5.Overcharge of refrigerant indicated by high wattage and sweating of the compressor return line
6.Thermostat not set for full cooling
7.Insufficient airflow through condenser due to: a) dirty condenser; b) loose belt; c) fan loose on shaft
8.Cutout on high pressure
9.Only one refrigerant circuit operational in
Remedy
1.Correct as follows: a) clean; b) defrost (using fan operation only); c) clean or replace filter; d) remove obstruction; e) check electrical system; f) adjust fan position.Tighten set screw on fan wheel.
2.Refer to original load calculations. Recalculate heat gain or loss.
3.Replace, if necessary.
4.Check refrigerant charge pressure with gauges. If refrigerant is low, recharge system.
5.Reclaim excess refrigerant.
6.Refer to thermostat operating instructions.
7.Correct as follows: a) clean coil; b) verify drive is adjusted correctly; c) tighten fan on shaft.
8.See that air is flowing and that damper is set properly.
9.Reset high pressure cutout on inoperative circuit. Check contactor in inoperative circuit.
Problem
Unit short cycles
Possible cause
1.Remote thermostat
2.Loose connection in electrical unit
3.Thermostat contacts fluttering
4.Air flow to evaporator is restricted
5.Insufficient charge
Remedy
1.Repair or replace.
2.Trace and repair.
3.Repair or replace.
4.Flush or blow dirt out of coil.
5.Reclaim, evacuate, recharge per nameplate.
Problem
Compressor starts and runs, but fan does not run.
Possible cause
1.Faulty switch
2.Open fan motor coil circuit
3.Fan binding on shroud or venturi ring
Remedy
1.Replace.
2.Replace.
3.Adjust fan mounting.
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