Middleby Marshall P/N 60250 Connection, Vii. Gas Supply, A. Gas Utility Rough-In Recommendations

Figure 2-17. Utility Connection Locations for Gas Ovens

Strain-relief

fitting

Electrical Junction Box (One per oven cavity)

Gas Inlet

(One per Single, Double,

or Triple Oven)

on the oven serial plate. The location of the serial plate is shown in Figure 1-1 (in Section 1, Description).

A fused disconnect switch or a main circuit breaker (customer furnished) MUST be installed in the electric supply line for each oven cavity. It is recommended that the switch/circuit breaker have Lockout/Tagout capability.

The supply conductors must be of the size and material (cop- per) recommended. Refer to the wiring diagram inside the machinery compartment of the oven. Electrical specifications are also listed on the oven’s serial plate and in Table 1-3, Electrical Specifications (in Section 1, Description).

The oven requires a ground connection to the oven ground screw. For gas ovens, the screw is located in the electrical junction box (see Figure 2-14). If necessary, have the electri- cian supply the ground wire. Do NOT use the wiring conduit or other piping for ground connections.

Incoming electrical power lines are fed through the strain-relief fitting, shown in Figure 2-14. The electrical supply connections are made inside the electrical junction box. The power lines then connect to the oven circuits through safety switches located inside the machinery compartment and each blower motor compartment. These switches interrupt electrical power to the oven when the Machinery Compartment Access Panel is opened, OR when the rear panel is removed.

Connection

Refer to the wiring diagram inside the machinery compart- ment of the oven to determine the correct connections for the electrical supply lines. Connect the supply as indicated on the wiring diagram.

CAUTION: The terms of the oven’s warranty require all

start-ups, conversions and service work to be performed by a Middleby Marshall Authorized Service Agent.

VII. GAS SUPPLY

CAUTION: DURING PRESSURE TESTING NOTE ONE OF

THE FOLLOWING:

1.The oven and its individual shutoff valve must be discon- nected from the gas supply piping system during any pressure testing of that system at test pressure in excess of ½ 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 ½ psi (3.45 kPa).

3.If incoming pressure is over 14″ W.C. (35mbar), a separate 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

•One or two cavities: 750 cfh meter

•Three oven cavities: 1200 cfh meter

Gas Line

•DEDICATED LINE from the gas meter to the oven

•2″ (50.8mm) pipe for natural gas

•2″ (50.8mm) pipe for propane

•Maximum length: 2002 (61m). Each 90°elbow equals 7″ (2.13m) of pipe.

17 P/N 60250 September 28, 2012