Middleby Marshall Essential Gas Conversion Instructions for Your Oven

SECTION 3 - SERVICING COMPONENTS

Appendix - Instructions for All Gas Conversion Kits

for Ovens with Wayne Burner, Propane to Natural Gas, 8/00

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5.The pilot pressure should be adjusted as follows:

•The current flow between the pilot hood and the flame sensor, when measured with a microamp meter or multimeter, holds constant at a minimum of 2.0 µA. See Figure 7.

•The pilot pressure as shown on the manometer is in the range of 3-1/2” - 4” W.C. (8.7-10.0 mbar).

Adjust the pilot pressure as necessary by turning the pilot adjustment screw on the combination gas control valve. Turning the screw clockwise decreases the pilot pressure. Turningthescrewcounter-clockwiseincreases the pressure.

Some valves may have a burr in the pilot adjustment portal. If you have fully tightened the adjustment screw, and the manometer still does not register a change in pressure, continue to tighten the screw to break through the burr. Back the screw out until its top is flush with the top of its hole, then tighten the screw again as necessary to adjust the pressure. Repeat this procedure as necessary to properly adjust the pilot pressure.

If the pilot pressure cannot be properly adjusted, switch the oven off and allow it to cool; then, replace the combination gas control valve. Repeat Section VII (Gas Leak Test) before attempting to adjust the pilot pressure again.

7.After the pilot pressure has been properly adjusted, replace the cap screw.

8.Reset the oven’s set point temperature to the customer’s original settings. Leave the oven in operation to allow the manifold pressure to be checked in the next Section of these instructions.

Figure 7

Flame sensor ( + )

Pilot hood ( - )

X. MANIFOLD PRESSURE ADJUSTMENT

1.Remove the regulator cap screw from the combination gas control valve.

2.Using a manometer, check the pressure at the manifold pressure tap, as shown in Figure 6. A manifold pressure of 3-1/2” W.C. (8.7mbar) is recommended for natural gas operation.

3.Adjust the pressure as necessary by turning the adjustment screw on the combination gas control valve. Turning the screw clockwise decreases the pressure. Turning the screw counter-clockwise increases the pressure.

If the manifold pressure cannot be properly adjusted, switch the oven off and allow it to cool; then, replace the combination gas control valve. Repeat Section VII (Gas Leak Test) before attempting to adjust the manifold pressure again.

4.After the manifold pressure has been properly adjusted, replace the cap screw. Record the final value on the Gas Conversion Label, as shown in Figure 8.

5.Switch the oven off, and allow it to cool.

XI. MARKING AND LABELING

1.Print the word “NATURAL” in the space provided on the Gas Control Conversion Tag, P/N 22501-0007. See Figure 8. Fasten the tag onto the gas piping next to the combination gas control valve.

2.Locate the round “LPG” label (red) on the burner or burner motor. Attach the kit-supplied yellow/green “NAT” label, P/N 22500-0064, on top of the “LPG” label. The new label should completely cover the “LPG” label. See Figure 8.

3.Complete the information on the Gas Conversion Label as shown in Figure 8.

4.Attach the Gas Conversion Label in plain view on the outside of the oven, as close as possilble to the oven’s serial plate.

Figure 8

Attach on top of existing “LPG” label (on burner or burner motor)

Attach to gas
piping next to
combination
gas valve	Name of	Date of
	technician	conversion

Part no. of this Kit - see chart on Page 1

New label completely

covers “LPG” label

Measured value from Section X

Stated on the oven’s	See chart on	Attach completed label in plain
		view near serial plate
serial plate	Page 1
	6

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