Turbo Chef Technologies 3240 manual Check for 24 VAC leaving the ignition module see , page

	To	From	Expected Resistance
Primary	Black	White (240 VAC Input)	28.1 W
	Black	Blue (240 VAC Input)	53.1 W
	Black	Red (240 VAC Input)	62.4 W
Secondary	Yellow	Yellow	0.80 W

Figure 33: Burner Transformer Ohm Chart

Combustion Blower

The combustion blower is a 3000 RPM, 208- 240 VAC, 0.33 A, 50/60 hz, blower motor. The winding resistance is 92 W. The combus- tion blower receives line voltage (208-240 VAC) from the K3 relay. Once the combustion blower reaches full speed, the air pressure switch closes, applying 24 VAC to the ignition module.

Testing Procedure

1.Disconnect line voltage from the unit.

2.Take a resistance reading of the winding; resistance should be 92 W. If resistance is incorrect, the combustion blower is damaged or defective and must be replaced (page A-14).

3.Apply line voltage to the unit and check for line voltage (208-240 VAC) applied to the winding when the unit is calling for heat and the K3 relay is closed.

4.If no voltage is present, inspect the wire harness for damage or shorts (page 45).

5.If the wire harness is intact and undamaged, the combustion blower is damaged or defective and must be replaced (page A-14).

Modulating Gas Valve

The modulating gas valve is a combination gas valve with a 24 VAC primary solenoid valve and 0.1-10 VDC modulating valve. The primary solenoid valve receives 24 VAC from the ignition module. The resistance of the primary solenoid valve is 535 k W. The modulating valve receives 0.1-10 VDC from the control board. The resistance of the modulating valve is 44 W. The modulating

valve has an adjustment shaft that adjusts the high and low flame pressure.

Testing Procedure

NOTE: See page 3 for instructions on adjusting the high and low flame gas pressure.

1.Disconnect line voltage from the unit.

2.Take a resistance reading of both coils, resistances should be 535k W and 44 W. If resistance is incorrect, the gas valve is damaged or defective and must be replaced (page A-14).

3.During warmup and cook mode, apply line voltage to the unit and check for 24 VAC at the primary solenoid coil and

0.1-10 VDC at the modulating valve coil.

4.If no voltage is present, inspect the wire harness for damage or shorts (page 45).

5.Check for 24 VAC leaving the ignition module (see Figure 35, page 28)

6.If wire harness is intact and undamaged, the modulating gas valve is damaged or defective and must be replaced (Pipe and valve assembly, page A-14).

Ignition Module

The ignition module generates 30,000 V at the spark igniter stud for direct ignition of the main burner when 24 VAC is applied. The module senses the presence of the burner flame and discontinues the ignition spark.

If the burner fails to ignite within 6 seconds, the module goes into safety lockout. If the burner does not maintain 1.5 DC uA mini- mum, the timed trial for ignition (6 seconds) is repeated and safety lockout occurs. If safety lockout occurs, power must be removed from the module before it can be restarted.

Testing Procedure

NOTE: The ignition module is different in domestic and international model ovens. Figure 34 shows the differences in the terminal labels between the two models.

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OVEN SYSTEMS