Middleby
®
Middleby Cooking Systems Group • 1400 Toastmaster Drive • Elgin, IL 60120 • (847)741-3300 • FAX (847)741-4406
Marshall
Oven Gas Conversion Kit p/n 36856
PS360EWB and PS360WB70
Natural Gas to Propane Installation Instructions
WARNING
This conversion kit is to be installed by a Middleby Marshall Authorized Service Organization in accordance with
the manufacturer’s instructions and all codes and requirements of the authority having jurisdiction. Failure to
follow instructions could result in serious injury or property damage. The authorized service organization
performing this work assumes responsibility for this conversion.
This kit consists of the following parts:
Qty.
Units p/n
Description
1
ea.
36857
Instructions for Conversion of Natural Gas Operation to Propane Operation, PS360EWB and
PS360WB70
1
1
1
1
1
ea.
ea.
ea.
ea.
ea.
31819
Orifice, Pilot Assembly - Propane, 0.025” (0.64mm)
Orifice, Main - Propane, 0.185” (4.70mm)
31822
22174-0009
22500-0065
22500-0123
Orifice, Low Flame - Propane, 0.034” (0.86mm, #62 drill) - used for converting PS360WB70 only
Label, LPG, Red
Label, Conversion - Gas
IMPORTANT
When converting any oven that is installed at an altitude above 5000 ft. (1524m), consult Middleby before installing
this Kit.
1. PREPARATION
1.1 Turn off the electric power supply to the oven.
1.2 Turn off the gas supply at the service valve behind the oven.
WARNING
Before performing any service or conversion work, the electrical power supply AND the gas supply MUST be
turned off.
1.3 Open the machinery compartment access door.
2. PILOT ORIFICE REPLACEMENT
2.1 Unscrew the brass fittings at both ends of the aluminum pilot tubing that connects the pilot orifice to the combination gas control
valve. This allows the tubing to be removed. See Figure 1.
Figure 1
Conversion component locations
Solenoid valve
(PS360WB70 only)
Main
orifice
holder
Low flame bypass
(PS360WB70 only)
Combination gas
control valve
Pilot
orifice
Aluminum
pilot tubing
p/n 36857
P. Jan 98 Rev. B
Page 1 of 4
6. INLET PRESSURE CHECK
6.1 Check the gas control inlet pressure at the inlet pressure tap. See Figure 6. An inlet pressure of 6-14” (14.9-34.9mbar) is
recommended for propane operation.
6.2 If the inlet pressure is:
•
HIGHER THAN 14” W. C. (34.9mbar) - This pressure may damage the combination gas control valve. Decrease the supplied
gas pressure.
•
LOWER THAN 3” W. C. (7.46mbar) - It may be necessary to increase the supplied gas pressure.
If it is necessary to adjust the gas line pressure, have the customer contact the gas utility supplier.
7. PILOT PRESSURE ADJUSTMENT
7.1 Ensure that the air supply is properly adjusted for propane operation.
•
Units with a burner blower air shutter (see Figure 5) should have the shutter opening (at its outside edge) set to 5/16”
(7.94mm). A drill bit can be used to check the adjustment of this opening.
•
Units without the air shutter (see Figure 5) should have the burner air supply adjustment screw turned 11-17 full revolutions
clockwise from the fully closed (counterclockwise) position. The screw is located on the front wall of the burner plenum, and
is surrounded by a “MORE AIR” label.
Figure 5
Burner blower configurations
Insert a 5/16”
(7.94mm) drill
bit to measure
opening
Blowers without
external air shutter
(remove before
operation)
External
air
OR
shutter
7.2 Before proceeding:
•
For a PS360EWB oven, the set point should be reduced
below the room temperature.
Figure 6
•
For a PS360WB70 oven, set the oven to low flame.
Gas pressure measurement/adjustment locations
7.3 Measure the pilot pressure at the pilot pressure tap, as shown
in Figure 6. The gas pressure should be 5-6” W. C. (12.5-
14.9mbar) for proper operation.
Pressure
regulator cap
screw
Pilot tube
connects
here
7.4 If necessary, adjust the pilot pressure as follows:
•
•
Remove the pilot adjustment cap screw.
Using a screwdriver, turn the inner adjustment screw
counterclockwise to increase, or clockwise to decrease,
the pilot gas pressure.
Pilot
adjustment
cap screw
•
Replace the cap screw and tighten it firmly.
Inlet pressure
tap
7.5 Measure the current across the pilot flame sensor. The
current must measure at least 2.0 µA. If the current reading
is too low, recheck the pilot pressure as per Step 7.3. If the
pressure reading is correct, consult the factory; otherwise,
repeat Steps 7.4 and 7.5.
Main orifice
pressure tap
8. MAIN MANIFOLD PRESSURE ADJUSTMENT
8.1 With the oven set to high flame, measure the regulated gas
pressure to the burner. The outlet pressure should be
checked at the main orifice pressure tap. See Figure 6.
The gas pressure should be 3” W. C. (7.46mbar) for proper
operation.
Pilot pressure
tap
8.2 If necessary, adjust the pressure regulator as follows:
•
•
Remove the pressure regulator cap screw.
Using a screwdriver, turn the inner adjustment screw clockwise to increase, or counterclockwise to decrease, the main
burner gas pressure.
•
Replace the cap screw and tighten it firmly.
8.3 Record the final measured regulated gas pressure on the silver conversion information label (included in the kit).
p/n 36857
P. Jan 98 Rev. B
Page 3 of 4
9. CONVERSION LABELING
Figure 7
Red “LPG.” label placement
9.1 Remove and discard the round, green “NAT.” label from the
(on burner housing)
front face of the burner plenum.
9.2 Apply the round, red “LPG.” label (p/n 22500-0065) to the front
face of the burner housing as shown in Figure 7.
9.3 Close the machinery compartment access door.
9.4 Record the information requested on the silver conversion
information label. Figure 8 shows a representation of this label.
9.5 Apply the conversion information label to the front of the
machinery compartment access door, next to the control panel.
See Figure 9.
Upper oven
label location
Lower oven
label location
Figure 8
Conversion information label
Signature of technician
performing conversion
Date of conversion
PROPANE
THIS APPLIANCE HAS BEEN CONVERTED ON _______________ TO ______________ GAS WITH KIT
36856
NO. ________________ BY _______________ , WHO ACCEPTS THE RESPONSIBILITY FOR
THE CORRECTNESS OF THIS CONVERSION.
.185”/ 4.70mm
MODEL NO.
MAIN BURNER ORIFICE SIZE
175,000 BTU
MANIFOLD PRESSURE
14” W.C./ 34.9mbar
INPUT RATING
MAXIMUM INLET PRESSURES
Measured value
recorded in Step 8.3
Stated on the
oven’s data plate
Figure 9
Conversion information label placement
THIS APPLIANCE HAS BEEN CONVERTED ON _______________ TO ______________ GAS WITH KIT
NO. ________________ BY _______________
,
WHO ACCEPTS THE RESPONSIBILITY FOR
THE CORRECTNESS OF THIS CONVERSION.
MODEL NO.
MAIN BURNER ORIFICE SIZE
MANIFOLD PRESSURE
INPUT RATING
MAXIMUM INLET PRESSURES
PS360EWB placement
THIS APPLIANCE HAS BEEN CONVERTED ON _______________ TO ______________ GAS WITH KIT
NO. ________________ BY _______________ WHO ACCEPTS THE RESPONSIBILITY FOR
,
THE CORRECTNESS OF THIS CONVERSION.
MODEL NO.
MAIN BURNER ORIFICE SIZE
MANIFOLD PRESSURE
INPUT RATING
MAXIMUM INLET PRESSURES
PS360WB70 placement
Page 4 of 4
P. Jan 98 Rev. B
p/n 36857
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