Frymaster SCFD, FPD manual Gas Valve, Improper Burner Function

DECATHLON SERIES GAS FRYERS

CHAPTER 1: SERVICE PROCEDURES

1.8.1 Ignition Failure (cont.)

The Gas Valve

If the problem is not in the 24 VAC circuit or pilot system, it is most likely in the gas valve. Before replacing the gas valve, refer to the troubleshooting guides in this chapter.

1.8.2 Improper Burner Function

In these instances, the burner ignites but exhibits abnormal characteristics, such as popping, incomplete lighting of the burner, fluctuating flame intensity, and flames “rolling” out of the fryer.

Popping indicates delayed ignition. In most cases, the main gas valve is opening, but the burner is not immediately lighting. When ignition does take place, excess gas ignites rapidly rather than smoothly.

The primary causes of popping are:

1.	incorrect or fluctuating gas pressure,	7.	heat damage to the controller or ignition module,
2.	misdirected or weak pilot flame,	8.	an out-of-adjustment ignitor or broken ignition wire,
3.	clogged burner orifices,	9.	a defective ignition module,
4.	clogged burner flame-transfer holes	10. missing or misaligned burner deflector targets, or
5.	clogged burners	11.	clogged vent tube (causing incorrect gas pressure).
6.	inadequate make-up air,

If popping occurs only during peak operating hours, the problem may be incorrect or fluctuating gas pressure. Verify that the incoming gas pressure (pressure to the gas valve) is in accordance with the appropriate CE or Non-CE requirements listed in the Installation and Operation manual that came with the fryer, and that the pressure remains constant throughout all hours of usage. Refer to Adjusting Burner Manifold Pressure in Section 1.4 if burner manifold pressure is suspected of being incorrect.

If popping is consistent during all hours of operation, verify that the pilot is properly positioned above the burner orifice and that the pilot pressure is correct. Correct pilot pressure is indicated by a flame 1 to 1½" long. Also verify that ignitor is properly adjusted (electrode tip 1/8" from pilot hood corner). Refer to Section 1.5 for pilot adjustment procedure.

Clogged burners, burner orifices, and burner flame transfer holes (see page 1-27 for reference) are also likely causes of delayed ignition. Clogged burners are indicated by uneven flame or partial flame on the burner face. Clogged orifices are indicated by no flame. Clogged burner flame transfer holes prevent the outermost burners from lighting immediately with the middle burners (four- and five-tube frypots).

Another cause of popping is an insufficient air supply or drafts that are blowing the pilot flame away from the burner. Check for "negative pressure" conditions in the kitchen area. If air is flowing into the kitchen area, this indicates that more air is being exhausted than is being replenished and the burners may be starved for air.

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