FGP55 SERIES GAS RETHERMALIZERS
CHAPTER 1: SERVICE PROCEDURES
1-21
1.7.1 Ignition Failures (cont.)
Problems Related to the Electronic Circuits
If gas and electrical power are supplied to the rethermalizer, the next most likely cause of ignition
failure is a problem in the 24 VAC circuit. First verify that the float switch valve is fully closed and
not sticking. (The float switch must be closed for power to reach the gas valve. Often, a starch build
up will cause the float switch to stick, impeding movement up and down the shaft. Simple cleaning
of the shaft will fix the problem.) If the float switch is fully closed refer to the troubleshooting
guides in this chapter.
Problems Related to the Gas Valve
If the problem is not in the 24 VAC circuit or pilot system, it is most likely in the gas valve itself, but
before replacing the gas valve refer to the troubleshooting guides in this chapter.
1.7.2 Improper Burner Functioning
With problems in this category, the burner ignites but exhibits abnormal characteristics such as
"popping", incomplete lighting of burner, fluctuating flame intensity, and flames "rolling" out of the
rethermalizer.
"
Popping
" indicates delayed ignition. In this condition, the main gas valve is opening but the burner
is not immediately lighting. When ignition does take place, the excess gas "explodes" into flame,
rather than smoothly igniting.
The primary causes of popping are:
•
Incorrect or fluctuating gas pressure
•
Misdirected or weak pilot flame
•
Clogged burner flame-transfer holes
•
Clogged burner orifices
•
Clogged burners
•
Inadequate make-up air
•
Heat damage to the controller or ignition module
•
An out-of-adjustment ignitor or broken ignition wire
•
A defective ignition module
