Middleby Marshall PS638 Series, Owner'S Operating And Installation Manual

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20
D. PS638G Propane/ULPG Conversion
Three items must be changed to change the oven to operate
on ULPG (
See Addendum for ULPG Conversion Kit #
74072)
1. Replace main orifices.
2. Replace the By-Pass orifice
3. Adjust main gas regulator.
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 on the manifold
assemblies with the ULPG orifices, and replace the manifold
assembly. Reconnect the union.
Loosen the By-Pass tube fitting to replace the By-Pass
orifice, tighten the tube fitting with the ULPG orifice inside
accordingly.
Remove the seal cap on the regulator and rotate the
adjustment screw in the clockwise direction to increase the
regulated pressure to 6”w.cc. (1.49kPa) at the manifold.
E. Adjusting the Maximum Pressure Setting
If maximum rate pressure needs adjustment, follow
instruction in section I. PS638G GAS SPECIFICATIONS
Figure 2-19. Gas Burner Assembly
Figure 2-20. Burner Components
F. Checkout
After any adjustment, set appliance in operation and observe
through a component cycle to ensure that burner system
components function correctly.
NOTE:
The installer
MUST
verify oven operation prior to
putting oven into service.
G. Maintenance
It is recommended to check yearly the minimum and the
maximum setting and readjust them if necessary.
H. Gas Train with Orificed By-Pass
For the Gas Trains that contain the Maxitrol Modulation
Valve and an mushroom spud orifice inside the by-pass
tube, no adjustments are required for the minimum
pressure setting.
Figure 2-21. By-Pass Tube and Orifice Location
FLAME TUBES
GAS BURNERS
M
ANIFOLD
P
RESSURE
T
AP