25
Burners and Igniters
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.
CAUTION
!
MainBurners
To access burners, remove burner accesspanel 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
projectiondimension for orifice face to manifold tube.
Orifice
1.00-in
(25.4 mm)
Manifold
Pipe
C08211
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.
C06153
Fig. 33 --Burner Tray Details
6. Remove igniter wires and sensor wires at the Integ-
rated GasUnit Controller (IGC). (See Fig. 34.)
7. Remove the 2 screws thatattach the burner rack to
the vestibuleplate (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-
moval and Replacement of GasTrain section, above.
2. Inspect burners; if dirty, remove burners from rack.
(Mark each burner to identify its positionbefore re-
moving from the rack.)
3. Use a soft brush to clean burners and cross--overport
as required.
4. Adjust spark gap. (See Fig. 35 and Fig. 36.)
5. If factory orifice has been removed, check thateach
orifice is tight at its threads into the manifold pipe
and that orifice projection does not exceed maximum
valve. See Fig.32
6. Reinstall burners on rack in the same locations as
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 INTEGRATED GAS UNIT
CONTROLLER (IGC)
HOLE IN END PANEL (HIDDEN)
C08454
Fig. 34 --Unit Control Box/IGC Location
7. Reinstall burner rack as described in Removal and
Replacement of Gas Train section, above.
Gas Valve — All three--phasemodel s (except Low NOx)
are equipped with 2--stage gas valves. Single--phase
models and all Low NOxmodels are equipped with
single--stage gas valves. See Fig. 37 for locations of
adjustmentscrews and features on the gas valves.
Toadjust gas valve pressure setti ngs:
IMPORTANT: Leakcheck all gas connectionsincluding
the main service connection, gas valve, gas spuds, and
manifold pipe plug. All leaks must be repaired before
firing unit.
CheckUnit Operation and Make Necessary Adjust-
ments
NOTE: Gas supply pressure at gas val ve inlet must be
within specified ranges for fuel type and unit size. See
Table4 and Table 5.
48TC