Middleby Marshall PS528G installation manual GAS Supply

V. GAS SUPPLY

CAUTION

DURING PRESSURE TESTING NOTE THE FOLLOWING:

1.The oven and its individual shutoff valve must be dis- connected from the gas supply piping system during any pressure testing of that system at test pressure in excess of 1/2 psi (3.45 kPa).

2.The oven must be isolated from the gas supply piping system by closing its individual manual shutoff valve dur- ing any pressure testing of the gas supply piping system at test pressure equal to or less than 1/2 psi (3.45 kPa).

3.If incoming pressure is over 14" W.C. (35mbar), a sepa- rate regulator MUST be installed in the line BEFORE the individual shutoff valve for the oven.

WARNING: To prevent damage to the control valve regu- lator during initial turn- on of gas, it is very important to open the manual shutoff valve very slowly.

After the initial gas turn-on, the manual shutoff valve must remain open except during pressure testing as outlined in the above steps or when necessary during service maintenance.

A.Gas Utility Rough-In Recommendations

The following gas system specifications are STRONGLY RECOMMENDED. Deviating from these recommendations may affect the baking performance of the oven.

Gas Meter - 650 cfh (307/min) meter

Gas Line

•DEDICATED LINE from the gas meter to the oven

•1-1/2" (38.1mm) pipe for natural gas

•1-1/2" (38.1mm) pipe for propane

•Maximum length: 200' (61m). Each 90° elbow equals 7'

(2.13m) of pipe.

B.Gas Conversion

Where permitted by local and national codes, it is possible to convert ovens from natural to propane gas, or from propane to natural gas. Use the appropriate Middleby Gas Conversion Kit for the specific oven model.

CAUTION: The terms of the oven’s warranty require all start- ups, conversions and service work to be performed by a Middleby Authorized Service Agent.

C.PS528 Propane Conversion

Two items have to be changed, to change the oven to LP:

1.Replace main orifices.

2.Adjust main gas regulator per instructions below.

Disconnect the manifold union closest to the main burner, and remove the manifold assembly (four screws). Slide out the manifold assembly (leaving the ignition and sense wires connected). Replace the main orifices.

Replace the main orifices on the manifold assemblies with the LP units, and replace the manifold assembly. Reconnect the union.

D.Adjusting the Maximum Pressure Setting

1.Disconnect pressure feedback connection (if applicable).

SECTION 2

INSTALLATION

2.Connect a suitable pressure gauge to pipe line or to outlet pressure tap of gas control concerned, to measure burner pressure (measuring point must be as near to burner as possible).

3.Make sure that the appliance is in operation and the Moduplus® coil is energized with maximum current.

4.If maximum rate pressure needs adjustment, use an 8 mm wrench to turn adjustment screw for maximum pressure setting

(clockwise to increase or counter-clockwise to decrease pressure), until the desired maximum outlet pressure is obtained.

5.Disconnect electrical connection of the Moduplus®.

6.Check minimum pressure setting and readjust if necessary. (SeeAdjusting Minimum Pressure Setting for proper adjusting procedure.)

7.Reconnect pressure feedback connection (if applicable).

8.If minimum and maximum pressures are set, wire the

Moduplus® in circuit.

9.Close pressure tap screw.

E.Adjusting the Minimum Pressure Setting

1.Disconnect pressure feedback connection (if appcable).

2.Connect a suitable pressure gauge to pipe line or to outlet pressure tap of gas control concerned, to measure burner pressure (measuring point must be as near to burner as possible).

3.Disconnect electrical connection of the Moduplus®.

4.Energize operator, set control in operation and wait until an outlet pressure is recorded on pressure gauge.

5.If minimum rate pressure needs adjustment, use an 8 mm wrench to turn adjustment screw for minimum pressure setting (clockwise to increase or counter-clockwise to decrease pressure), until the desired minimum outlet pressure is obtained.

6.Check if main burner lights easily and reliable at minimum pressure.

7.Reconnect pressure feedback connection (if applicable).

8.Close pressure tap screw.

Figure 2-15 - Flexible Gas Hose Installation

1/2" gas	3/4"-1/2"
pipe nipple
		gas pipe
			To Gas
		reducer
			Supply
			Pipe
		3/4" gas
1/2" gas		pipe nipple
line tee with	90°
pressure tap
		Elbow
			Full-Flow
			Gas
			Shutoff
			Valve
		Flexible	Individual gas
Quick-			connection
		Gas Hose
			for each oven
disconnect
			cavity
device

15