Troubleshooting Gas Burners

As is the case with all mechanical and electrical equipment, it is recognized that occasional repair and adjustment may be necessary on any burner. Table 2-4 represents a very general list of troubles and causes that can occur with gas burners and gives some suggested remedies.

Table 2-4 Troubleshooting Gas Burners

Symptom and Possible Cause Possible Remedy
Pilot does not light.
(a) Air in gas line. (a) Clear or replace line.
(b) High or low gas pressure. (b) Check for possible gas supply problem with local gas company; replace defective burner.
(c) Blocked pilot orifice. (c) Clean orifice or replace.
(d) Flame runner improperly located. (d) Move to correct location.
Pilot goes out frequently during standby or safety switch needs frequent resetting.
(a) Restriction in pilot gas line. (a) Clear or replace line.
(b) Low gas pressure. (b) Check for possible gas supply problem first with local gas company; Replace defective burner.
(c) Blocked pilot orifice. (c) Clear blockage or replace.
d) Loose thermocouple connection on 100 percent shutoff. (d) Secure connection or replace defective thermocouple.
(e) Defective thermocouple or pilot safety switch. (e) Replace thermocouple or pilot safety switch.
(f) Poor draft connection. (f) Correct.
(g) Draft tube set into or flush with inner wall of combustion chamber. (g) Move tip of draft tube to proper location.
Pilot goes out when motor starts.
(a) Restriction in pilot gas line. (a) Remove restriction or replace line.
(b) High or low gas pressure. (b) Check for possible gas supply problem with local gas company; replace defective burner.
(c) Excessive pressure drop when main gas valve opens. (c) Check for possible gas supply problem with local gas company; test main gas valve and replace if defective.
Burner motor does not run.
(a) Burned-out fuse or tripped circuit breaker. (a) Replace fuse or reset circuit breaker. If problem continues, call an electrician.
(b) Thermostat or limit defective or improperly set. (b) Reset thermostat or limit, or replace if defective.
(c) Relay or transformer defective. (c) Replace relay or transformer.
(d) Motor burned out. (d) Replace motor or burner.
(e) Tight motor bearings from lack of oil. (e) Lubricate bearings; repair or replace damaged bearings.
(f) Improper wiring. (f) Check wiring diagram for burner and rewire correctly.
Burner motor running but no flame.
(a) Pilot out. (a) Relight pilot or replace defective pilot.
(b) Pilot safety switch needs to be reset. (b) Reset switch.
(c) Thermocouple not generating sufficient voltage. (c) Replace defective thermocouple.
(d) Very low or no gas pressure. (d) Check for possible gas supply problem with local gas company; check for obstruction in gas line and correct.
(e) Motor running too slow. (e) Replace defective motor.
Short and/or noisy burner flame.
(a) Pressure regulator set too low. (a) Change to proper setting.
(b) Air shutter open too wide. (b) Correct opening size.
(c) Too much pressure drop in gas line. (c) Check for possible gas supply problem with local gas
company; check for obstruction in gas line and correct.
(d) Vent in regulator plugged. (d) Clear vent.
(e) Defective regulator. (e) Replace regulator.
Long yellow flame.
(a) Air shutter not open enough. (a) Adjust opening.
(b) Air openings or blower wheel clogged. (b) Clear.
(c) Too much input. (c) Reduce input.
Main gas valve does not close when blower stops.
a) Defective valve. (a) Replace valve.
(b) Obstruction on valve seat. (b) Remove obstruction.