Inadequate burner tip design for the mixture pressure developed particularly the flame retention. Faulty flue or combustion chamber design also will have an effect on burner performance but basically these three factors should be checked first if troubles arise. It has been proven that many problems have rather simple causes. The following are the most frequent faults in a forced draft type burner installation and probable remedies. Check all gas cocks are open and the regulator is reset if required.
Check fuses, thermostats, and electrical connections.
The fan motor fails to start. Safety unit is locked out, air pressure switch is faulty or incorrectly adjusted, fan motor or safety unit defective. After The Pre-Purge Time Has Elapsed No power on the solenoid terminals. Check the flame safety relay and replace. The ignition or sensing electrodes are touching, the porcelain is cracked, they are touching earth or incorrectly positioned.