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

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10. Turn the gas supply to the oven off. Open the
tap screw in the manifold pressure tap fitting
one full turn. Connect a silicone tube between
the manifold pressure tap and a digital
manometer. Make sure to zero the meter before
performing the next step.
11. Turn the gas supply on.
12. Reconnect power to the oven. Pull out the door
interlock switch and turn the oven on. After
approximately 15 seconds, the gas valve will
open and the ignition system should light the
gas at the burners. Set the oven temperature
to 550
o
F (288
o
C) and allow the oven to heat to
300
o
F (149
o
C).
13. With the HEAT percentage on the user
interface showing 100%, check the gas
manifold pressure and adjust the plastic
adjuster screw if necessary. Clockwise will
increase the pressure and counter-clockwise
will decrease the pressure. The proper setting
for the propane gas pressure is 6.0 inch water
column (1.5 KPa, 14.9 mbar).
14. Once the gas pressure has been adjusted
replace the cap on the combination gas control
valve that was removed in step 2 above.
15. Turn the oven off and turn off the gas supply.
16. Remove the silicone tube from the pressure tap
and thread the sealing screw in by turning it
fully clockwise and tightening it snugly. DO
NOT OVER TIGHTEN.
17. Attach the appropriate ULPG labels that were
supplied in the Middleby propane conversion kit
over the existing Natural gas labels.
18. Fill in the information on the blank label using a
permanent marker stating the oven was
converted from Natural gas to ULPG and apply
the label next to the data plate label on the
oven control door.
19. Turn on the gas supply. The oven is now ready
for operation.
Manifold Pressure Tap