Carrier 48TCA04---A12 Service And Maintenance Instructions page 25

Burners and Igniters
CAUTION
!
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in
equipment damage.
When working on gas train, do not hit or plug
orifice spuds.
Main Burners
To access burners, remove burner access panel and slide
out burner partition. At the beginning of each heating
season, inspect for deterioration or blockage due to
corrosion or other causes. Observe the main burner flames
and adjust, if necessary.
Orifice projection — Refer to Fig. 32 for maximum
projection dimension for orifice face to manifold tube.
1.00-in
(25.4 mm)
Manifold
Pipe
Fig. 32 - - Orifice Projection
Removal and Replacement of Gas Train
See Fig. 27, Fig. 31 and Fig. 33.
1. Shut off manual gas valve.
2. Shut off power to unit.
3. Slide out burner partition.
4. Disconnect gas piping at unit gas valve.
5. Remove wires connected to gas valve. Mark each
wire.
Fig. 33 - - Burner Tray Details
6. Remove igniter wires and sensor wires at the Integ-
rated Gas Unit Controller (IGC). (See Fig. 34.)
7. Remove the 2 screws that attach the burner rack to
the vestibule plate (Fig. 31).
8. Slide the burner tray out of the unit (Fig. 33).
9. To reinstall, reverse the procedure outlined above.
Cleaning and Adjustment
1. Remove burner rack from unit as described in Re-
2. Inspect burners; if dirty, remove burners from rack.
3. Use a soft brush to clean burners and cross- - over port
4. Adjust spark gap. (See Fig. 35 and Fig. 36.)
5. If factory orifice has been removed, check that each
6. Reinstall burners on rack in the same locations as
Orifice
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7. Reinstall burner rack as described in Removal and
Gas Valve — All three- - phase models (except Low NO
are equipped with 2- - stage gas valves. Single- - phase
models and all Low NO
single- - stage gas valves. See Fig. 37 for locations of
adjustment screws and features on the gas valves.
To adjust gas valve pressure settings:
IMPORTANT: Leak check all gas connections including
the main service connection, gas valve, gas spuds, and
manifold pipe plug. All leaks must be repaired before
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firing unit.
Check Unit Operation and Make Necessary Adjust-
ments
NOTE: Gas supply pressure at gas valve inlet must be
within specified ranges for fuel type and unit size. See
Table 4 and Table 5.
25
moval and Replacement of Gas Train section, above.
(Mark each burner to identify its position before re-
moving from the rack.)
as required.
orifice is tight at its threads into the manifold pipe
and that orifice projection does not exceed maximum
valve. See Fig. 32
factory- - installed. (The outside crossover flame re-
gions of the outermost burners are pinched off to pre-
vent excessive gas flow from the side of the burner
assembly. If the pinched crossovers are installed
between two burners, the flame will not ignite prop-
erly.)
RACEWAY
HOLE IN END PANEL (HIDDEN)
Fig. 34 - - Unit Control Box/IGC Location
Replacement of Gas Train section, above.
models are equipped with
x
INTEGRATED GAS UNIT
CONTROLLER (IGC)
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)
x