Carrier 48TC series, Service And Maintenance Instructions

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35
Fig. 50 — Orifice Projection
Removal and Replacement of Gas Train
See Fig. 44, 49, and 51.
1. Shut off the gas using the manual shutoff switch located in
the gas supply line.
2. Turn the gas valve ON/OFF knob to the OFF position.
3. Shut off power to the unit and install a lockout tag.
4. Disconnect the gas piping at the unit gas valve.
5. Remove the wires connected to the gas valve. Mark each wire
to assist in reconnecting power to the gas valve.
6. Remove the igniter wires and sensor wires at the Integrated
Gas Unit Controller (IGC). See Fig. 53.
7. Remove the 2 screws that attach the burner rack to the vesti -
bule plate. See Fig. 51.
8. Slide the burner tray out of the unit (see Fig. 52).
9. To reinstall, reverse the procedure outlined above.
Fig. 51 — Burner Assembly Removal
Fig. 52 — Burner Tray Details
Cleaning and Adjustment
1. Remove the burner rack from the unit as described in the
Removal and Replacement of Gas Train section.
2. Inspect the burners; if dirty, remove the burners from rack.
(Mark each burner to identify its position before removing
from the rack.)
3. Use a soft brush to clean the burners and cross over port as
required.
4. Adjust the spark gap. The gap should be 0.12 to 0.14-in. (3.06
to 3.60 mm) and spaced 0.18-in. (4.60 mm) from the end of
the burner. (See Fig. 55)
5. If the factory orifice has been removed, check that each ori -
fice is tight at its threads into the manifold pipe and the orifice
projection does not exceed the maximum value. See Fig. 50.
6. Reinstall burners on rack in the same locations as they were
installed at the factory. The outside crossover flame regions
of the outermost burners are pinched off to prevent excessive
gas flow from the side of the burner assembly. If the pinched
crossovers are installed between two burners, the flame will
not ignite properly.
7. Reinstall the burner rack as described in the Removal and
Replacement of Gas Train section.
CAUTION
PERSONAL INJURY HAZARD
Failure to follow this caution can result in personal injury.
Disconnect all electrical power when servicing the fan motor.
Apply appropriate lockout/tag-out procedures.
ORIFICE
1.00-in
(25.4 mm)
MANIFOLD
PIPE
BURNER
ASSEMBLY
GAS VALVE
VESTIBULE
PLATE
SCREWS
MANIFOLD
PRESSURE TAP
~
3
2
1
1
ITEM NO. DESCRIPTION
1 Gas manifold mounting screws (qty 2)
2 Gas valve inlet plug
3
Propane conversion label (apply label where
indicated)