Trane SCWH - Manual (Page 31)

PKG-SVX14A-EN 31
Maintenance
troubleshooting
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 2-circuit units
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
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. 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.
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.
Remedy
1. Replace.
2. Replace.
3. Adjust fan mounting.
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.