Sterling QVEB - Manual (Page 21)

9. Loose wiring.
10. Defective ignition control.
1. Improper venting.
1. Poor thermostat location.
2.
Defective thermostat.
3. Improper thermostat or transformer wiring
at gas valve.
4. Short circuit.
5. Defective or sticking gas valve.
6. Excessive gas supply pressure.
1. Loose electrical connections at gas valve,
ignitor, pilot or thermostat.
2. Excessive thermostat heat anticipation
cycles.
3. Unit cycling on high limit.
4. Poor thermostat location.
5. Draft on Pilot.
6. Defective ignitor control.
7. Blower motor turning too slowly.
8. Defective high limit switch.
1. Blower wheel loose.
2. Blower wheel blades dirty.
3. Blower wheel rubbing housing.
4. Bearings are dry.
5. Pulleys loose.
1. Main gas off.
2. Pilot adjustment screw turned too low on
combination/automatic main gas valve.
3. Air in gas line.
4. Incorrect lighting procedure.
5. Dirt in pilot orifi ce.
6. Extremely high or low gas pressure.
7. Defective spark cable.
8. Drafts around unit.
9. Pilot valve not opening (faulty wiring).
10. No spark (faulty wiring).
11. Defective gas valve/ignitor control.
1. Loose wiring.
2. Defective motor overload protector or
defective motor.
9. Check and tighten all wiring connections
per diagrams.
10. Replace, if necessary. Also see W, X & Y
symptoms.
1. Refer to “Installation, Venting”.
1. Relocate thermostat away from drafts.
2.
Replace thermostat.
3. Check wiring per diagrams.
4. Check operation at valve. Look for short
(such as staples piercing thermostat wiring),
and correct.
5. Replace gas valve.
6.
Refer to “Operation”.
1. Tighten all electrical connections.
2. Adjust thermostat heat anticipator for
longer cycles. Refer to “Operation”.
3. Check for proper air supply across heat
exchanger.
4. Relocate thermostat. (Do not mount
thermostat on unit).
5. Eliminate drafts. Refer to Installation.
6.
Replace ignitor.
7. Clean blower wheel blades; oil blower
motor; check for voltage to blower fan.
Refer to “Maintenance” section.
8. Jumper limit switch terminals 1 and 2.
If burner operates normally, replace switch.
1. Replace or tighten.
2. Clean fan wheel.
3.
Realign.
4. Oil bearings on blower motor. (Refer to label
on motor).
5. Replace or tighten.
1. Open all manual gas valves.
2. Increase size of pilot fl ame. Refer to
“Operation”.
3. Purge air from gas supply.
4. Follow lighting instruction label adjacent to
gas valve.
5. Remove pilot orifi ce. Clean with compressed
air or solvent. (Do not ream).
6. Refer to “Operation”.
7. Check spark cable connection,
and replace if defective.
8. Eliminate drafts. Refer to “Installation”.
9. Inspect and correct all wiring.
10. Inspect and correct ignition system wiring.
See symptoms W, X, & Y.
11. Replace.
1. Check and tighten all wiring connections
per diagrams. Thermostat wires tagged “W”
and “G” must be connected together (unless
special thermostats are used; if so, see
thermostat wiring diagram). See electrical
connections.
2. Replace motor.
Power Vented Blowers Troubleshooting Guide
SYMPTOMS POSSIBLE CAUSE(S) CORRECTIVE ACTION
H. continued
J. Condensation of water vapor.
K. Burner won't turn off.
L. Rapid burner cycling.
M. Noisy
N. Pilot will not light or will not
stay lit.
O. Fan will not run.
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