Middleby Marshall PS224 PS310 Main Orifice Replacement, Gas Leak Test, Pilot orifice assembly

SECTION 3 - SERVICING COMPONENTS

Appendix - Instructions for Service Kit 36863 - Gas Conversion Kit for PS360EWB/WB70 with Midco Burner, Propane to Natural Gas, 1/98

2.2Remove and retain the aluminum pilot tubing from the burner assembly. The end of the tubing that enters the combination gas control valve should be removed first.

2.3Remove and retain the pilot orifice by unscrewing it (counterclockwise) from the burner plenum wall.

2.4Unscrew and retain the pilot tubing connector and the pilot tap plug from the ends of the pilot orifice, as shown in Figure 2. When these attachments have been removed, discard the pilot orifice.

2.5Screw the pilot tubing connector and the pilot tap plug into place in the new propane pilot orifice (p/n 31819). Tighten them to a snug fit.

2.6Screw the new propane pilot orifice into its opening in the plenum wall. Tighten it to a snug fit. Ensure that the end of the orifice holding the pilot tubing mount points towards the piping assembly.

2.7Replace the aluminum pilot tubing that was removed in Step 2.2, above.

2.8Screw in the brass fittings at both ends of the aluminum pilot tubing. Tighten them to a snug fit. DO NOT OVERTIGHTEN THE FITTINGS.

3. MAIN ORIFICE REPLACEMENT

3.1Remove and retain the main orifice holder by unscrewing it (counterclockwise) from the burner plenum wall.

3.2Unscrew and discard the main orifice from the inner end of the holder, as shown in Figure 3.

3.3Screw the new natural gas main orifice (p/n 31821) into the orifice holder. Tighten it to a snug fit.

3.4Replace the main orifice holder into its opening in the burner plenum. Tighten it to a snug fit.

4. LOW FLAME ORIFICE REPLACEMENT (PS360WB70 only)

4.1Unscrew the brass fittings at both ends of the aluminum low flame tubing. This allows the tubing to be removed. See Figure 4.

4.2Remove and retain the tubing from the solenoid valve.

4.3Remove and discard the low flame orifice from the end of the low flame tubing.

4.4Insert the new natural gas low flame orifice (p/n 22174-0006) into the discharge end of the low flame tubing, as shown in Figure 4.

4.5Replace the low flame tubing into the fittings on the solenoid valve.

4.6Screw in the brass fittings at both ends of the aluminum low flame tubing. Tighten them to a snug fit.

5. GAS LEAK TEST

Figure 2

Pilot orifice assembly

Pilot tubing connector

Pilot tap plug

Pilot orifice

Figure 3

Main orifice and holder

Main orifice

holder

Main orifice

Main manifold tap plug (leave in place)

Figure 4

Low flame orifice replacement

Aluminum

tubing

	Low flame							er
							rn
		orifice				To	bu
					n
			atio
		bin
	m				e
	co
m				alv
			lv
Fro	ntro
sco
ga

Solenoid valve

5.1Paint all pipe connections from the gas union to the burner plenum, and the aluminum pilot and low flame orifice tubing connections, with a solution of soap and water (2/3 soap, 1/3 water is recommended). Any bubbles that are visible indicate a gas leak.

5.2If a gas leak is detected, tighten the affected joints and connections. If tightening the connections fails to stop the leak, replace the affected component and repeat the gas leak test.

WARNING - FIRE / EXPLOSION HAZARD

Hidden gas leaks can cause a flashback in the machinery compartment. THIS CAN CAUSE SEVERE INJURY OR DEATH. Stand well clear when switching on the heating circuit.

5.3If no leaks are detected by the test, switch on the oven. Switch on the heating circuit to ignite the main burner.

5.4With the burner in operation, paint all gas pipe joints with the solution of soap and water.

5.5If any further gas leaks are detected, shut down the oven. Reseal and tighten the affected joints and connections. If tightening the connections fails to stop the leak, replace the affected component(s) and repeat the gas leak test.

Page 2 of 4 P. Jan. 98 Rev B p/n 36862

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