English – Middleby Marshall PS360WB-U User Manual

Page 13

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13

ENGLISH

C. Preparation for Use with Various Gases
Before proceeding to set up the oven for a specific gas, check

that the main gas supply valve and the circuit breaker/fused

disconnect are in the OFF ("O") position.
The main and pilot orifices must match the sizes shown in the

Gas Orifices and Pressure Specifications table, near the

beginning of this Section. If necessary, replace the orifices.

Refer to Part D, Replacing the Gas Orifices.
The orifice (manifold) pressure should be adjusted to the value

shown in the Gas Orifices and Pressure Specifications table for

the specific gas type and location.
1. For Use with Natural Gas

The actual heat input to the oven must match the rated heat

input. The input to the burner can be determined using the

orifice (manifold) pressure data or by the volume supplied

using the gas meter. Both of these procedures are

described in Part F, Adjusting the Orifice (Manifold) Pressure

and Heat Input.
If the measured input does not correspond with the rated

input (shown in the Gas Orifices and Pressure Specifications

table), check first that the correct orifices are installed. If the

orifices are correct, check and correct the supply and orifice

pressures to obtain the correct input based on the gas

meter reading.

2. For Use with Liquid Propane (LP) Gas

When using liquid gas, the converter in the multifunction

gas valve must be removed, and then replaced INVERTED

from its former position. See Figure 2-16. Inverting the

converter will disable the governor. This step is only

required if the supply pressure is below 50mbar.

D. Replacing the Gas Orifices (if so required)
1. Replacing the Main Orifice

a. Check that the main gas supply valve and the circuit

breaker/fused disconnect are in the OFF ("O") position.

b. Open the union in the gas supply line. The union is

shown in Figure 2-16, on the previous page.

c. Refer to Figure 2-17. Unscrew the four hex screws that

hold the venturi mounting plate to the front of the

burner. Remove the gas train/venturi assembly from

the oven.

d. Remove the two 1/2" nuts that secure the gas train to

the venturi mounting plate.

e. Remove the main orifice using an 11/16" wrench.
f.

Install the new orifice.

2. Replacing the Pilot Orifice

NOTE: All natural gases use the same size pilot orifice

(0,635mm), as do all liquid propane (LP) gases (0,381mm).

Because of this, it is not normally necessary to replace the

pilot orifice unless converting the oven from natural to

propane, or from propane to natural, operation.
a. Refer to Figure 2-17. Unscrew the pilot tube

compression nut and slide it out of the way. Pull the

tube from the fitting to expose the pilot orifice.

b. Remove the pilot orifice.
c. Slip the new pilot orifice into the pilot tube.
d. Push the pilot tube back into place until it bottoms, and

hold it in place. Slide the compression nut back into

place and engage the threads. Tighten the nut to a

snug fit with your fingers.

e. Gently tighten the nut one complete turn with a wrench.

DO NOT OVERTIGHTEN THE COMPRESSION NUT.

3. Replacing the Bypass (Low Flame) Orifice

a. Refer to Figure 2-16. Note the locations of the 1/2" hex

compression nuts that hold the bypass line in place.

Loosen the compression nuts using a 1/2" wrench.

b. Remove the bypass tube. Then, remove the bypass

orifice from the tube.

c. Slip the new orifice into the bypass tube.
d. Replace the tube onto its fittings on the solenoid valve.

While holding the tube in place, slide the compression

nuts back into place and engage the threads. Tighten

the nut to a snug fit with your fingers.

e. Gently tighten the nuts one complete turn with a wrench.

DO NOT OVERTIGHTEN THE COMPRESSION NUTS.

f.

Replace the gas train and venturi by following Steps a-

d in Replacing the Main Orifice, above, in reverse order.

WARNING

After completing these procedures, perform a gas

leak test before operating the oven.

Figure 2-17 - Replacing the Main and Pilot Orifices

Main

orifice

Pilot

orifice

Pilot tube

Compression

nut

Main orifice

holder (attached

to gas train)

Venturi

assembly

Venturi

mounting

plate

Ignition

sensor

wire

SECTION 2 - INSTALLATION

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