Trane GUNE, Installation, Operation And Maintenance Manual

Page: 36 / 39

Troubleshooting
36 GUNE-SVX001A-EN
Too much heat.
Unit is over fired.
Refer to “Gas Input Rate,” p. 28 . Check orifice size.
Replace if too large.
Thermostat malfunction.
Check thermostat for operation, to ensure circuit open
and closes.
Unit runs continuously.
Check wiring per diagram. Check operation at the gas
valve. Look for a short in thermostat circuit.
Defective gas valve.
Replace valve and check pressure setting (see Table 5,
p. 15 ).
Excessive gas supply pressure. Refer to Table 5, p. 15 .
Incorrect airflow. See blower manufacturer for corrective action(s).
Cold air is delivered during
heater operation.
Incorrect manifold pressure or gas input. Test and reset manifold pressure (see Table 5, p. 15 .)
Incorrect airflow. See blower manufacturer for corrective action(s).
High limit is tripping.
Unit is over fired.
Refer to “Gas Input Rate,” p. 28 . Check orifice size.
Replace if too large.
Incorrect airflow. See blower manufacturer for corrective action(s).
Defective high limit switch.
Check operation of switch. If switch is open during
operation, check gas pressure and/or CFM; adjust
accordingly. If switch is open during start-up, replace
switch.
Defective control board.
Check for 24 V on line side of high limit. Constant
voltage should be recorded. If not, control board is
suspect. Check flash code.
Power ventor will not run.
No power supply to the unit. Turn on power supply, check fuses and replace if bad.
Thermostat not calling.
Turn up thermostat. Check for 24 V on terminals R and
W1 on terminal strip.
Loose wiring or connection.
Check all wiring in the power vent circuit to ensure good
connection, including “neutral.”
Motor overload protection is tripping or bad motor.
Check for 115V between motor leads and check amp
draw of motor. Replace if necessary.
Defective control board.
Check for continuous 115 V on terminal “CBM Blower”
and neutral during call for heat. If not present and all
checks are normal, replace.
Motor not oiled. Refer to “Maintenance,” p. 31 .
Power venter turns on and off
during operation.
Power venter improperly wired. Check power venter circuit per wiring diagram.
Main burner did not light on call for heat.
Check motor voltage and amp draw against motor name
plate, replace if motor found defective.
Defective control board.
Check for continuous 115 V on terminal “CBM Blower”
and neutral during call for heat. If not present and all
checks are normal, replace.
Motor not oiled. Refer to “Maintenance,” p. 31 .
Power venter will not stop.
Power venter improperly wired. Check power venter circuit per wiring diagram.
Main burner did not light on call for heat.
Heater is in lockout mode; check flash code table for
problem.
Defective control board.
If no flash codes present along with no call for heat,
replace control board.
Noisy power venter.
Power venter wheel loose. Replace or tighten.
Power venter wheel is dirty. Clean power venter wheel.
Power venter wheel is rubbing on housing. Realign power venter wheel.
Bearings are dirty.
Oil bearing on power venter motor (refer to label on
motor).
Table 14. Tubular duct furnace troubleshooting guide
Symptoms Possible Cause(s) Corrective Action