Middleby Marshall PS540 installation manual III. STEP-BY-STEP Operation

SECTION 3

OPERATION

WARNING

OVEN MUST BE KEPT CLEAR OF

COMBUSTIBLES AT ALL TIMES.

III. STEP-BY-STEP OPERATION

Control Panel (On split belt ovens, two conveyor speed controls are mounted on the control panel.)

A. Startup Procedures

Initial Startup

Check that the full-flow gas shutoff valve is “on”. This valve is located outside the rear of the oven. See Figures 2-3, 2-4, and 2-5.

Daily Startup

1.Turn the BLOWER switch (Figure 3-6) to the “ON” or “I” position. This starts the main blower fan and the cooling fan. The blower circulates air through the air fingers and must stay on during the cooking or baking process.

2.Check to see if the cooling fan (see Figure 1-8) is operating when the blower switch (see Figure 3-6) is turned “ON” or “I”. The cooling fans cool the control components and burner blower motor. The cooling fan, located at the rear of the electrical control cabinet blows air into and through the cabinet. Air is exhausted through the front of the cabinet and also out the front of the oven. Refer to Daily Maintenance Section for fan intake checking procedure.

IMPORTANT NOTE

The cooling fan operates when the BLOWER switch is turned “ON” or “I”. It must operate to keep the control console below 140°F (60°C).

3.Turn the CONVEYOR switch (Figure 3-6) to the “ON” or “I” position. This starts the conveyor belt moving through the oven. Set the conveyor speed for the desired baking time. Refer to the following Procedures E, F and G.

4.Set the temperature controller to the desired baking temperature. See section on bake times to determine desired temperature.

NOTE: For complete temperature controller operation instructions refer to Step C.

5.Turn the HEAT switch (Figure 3-6) to the “ON” or “I” position. This completes a circuit to supply electric power to the burner. When an oven that has not been in operation for approximately 1/2 hour is turned on, it goes through a 30-second purge cycle. The burner blower motor will not operate during the time the blower fan is purging the oven. After 30 seconds, the burner blower motor starts, which can be detected by feeling a slight vibration when touched. This permits the burner to light.

When in operation, the burner is either on low or high flame. Its flame-sensing electrode must be satisfied to keep the bypass and gas valves open. If for some reason the bypass flame is extinguished, the burner tries to relight for 90 seconds. If the burner flame does not relight in 90 seconds, the oven goes into automatic safety lockout.

To relight the oven, turn the HEAT switch to “OFF” or “O” for 5 minutes. Then, repeat the Oven Startup procedure.

6.Close front window.

7.Oven will reach a baking temperature of 600°F (315°C) in approximately 10 minutes. Allow the oven to cycle for

30minutes after it has reached desired bake temperatue. The oven is now ready for baking.

Power Failure

In case of power failure, turn off all switches; open oven window and remove product. After power has been reestablished follow normal startup procedure.

CAUTION

The burner will not operate and gas will not flow through the burner without electric power. No attempt should be made to operate the oven during power failure.

B. Shutdown Procedure

1. Turn the BLOWER and HEAT switches to “OFF” or “O”.

NOTE: The blowers will remain on until the oven tempera- ture cools down to 200°F (93°C) at which time they will stop automatically.

2.Make certain that there are no products left on the conveyor inside the oven. Turn the CONVEYOR switch to “OFF” or “O”.

3.Turn off the main gas supply valve.

4.Open the oven window.

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