Bryant Preferred 581J04-14, Service And Maintenance Instructions, Page: 32 / 148

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GAS VALVE
All three-phase models (except Low NOx) are equipped with
2-stage gas valves. Single-phase models and all Low NOx
models are equipped with single-stage gas valves. See Fig. 59
for locations of adjustment screws and features on the gas
valves.
To adjust gas valve pressure settings:
CHECK UNIT OPERATION AND MAKE NECESSARY
ADJUSTMENTS
NOTE: Gas supply pressure at gas valve inlet must be within
specified ranges for fuel type and unit size. See Tables 8 and 9.
1. Remove manifold pressure tap plug from manifold and
connect pressure gage or manometer. (See Fig. 53.)
2. Turn on electrical supply.
3. Turn on unit main gas valve.
4. Set room thermostat to call for heat. If unit has two-stage
gas valve, verify high-stage heat operation before attempt-
ing to adjust manifold pressure.
5. When main burners ignite, check all fittings, manifold,
and orifices for leaks.
6. Adjust high-stage pressure to specified setting by turning
the plastic adjustment screw clockwise to increase pres-
sure, counter-clockwise to decrease pressure.
7. For two-stage gas valves, set room thermostat to call for low-
stage heat. Adjust low-stage pressure to specified setting.
8. Replace regulator cover screw(s) when finished.
9. With burner access panel removed, observe unit heating
operation in both high stage and low stage operation if so
equipped. Observe burner flames to see if they are blue in
appearance, and that the flames are approximately the
same for each burner.
10. Turn off unit, remove pressure manometer and replace the
1 /
8
-in. pipe fitting on the gas manifold. (See Fig. 52.)
LIMIT SWITCH
Remove blower access panel. Limit switch is located on the
fan deck. See Fig. 47.
Burner Ignition
Unit is equipped with a direct spark ignition 100% lockout sys-
tem. The Integrated Gas Unit Controller (IGC) is located in the
control box (see Fig. 54). The IGC contains a self-diagnostic
LED (light-emitting diode). A single LED (see Fig. 60) on the
IGC provides a visual display of operational or sequential prob-
lems when the power supply is uninterrupted. When a break in
power occurs, the IGC will be reset (resulting in a loss of fault
history) and the indoor (evaporator) fan ON/OFF times will be
reset. The LED error code can be observed through the viewport.
During servicing, refer to the label on the control box cover or
Table 12 for an explanation of LED error code descriptions.
If lockout occurs, unit may be reset by interrupting power sup-
ply to unit for at least 5 seconds.
LEGEND
* A 3-second pause exists between LED error code flashes. If more
than one error code exists, all applicable codes will be displayed in
numerical se
q uence.
† Indicates a code that is not an error. The unit will continue to operate
when this code is displayed.
Orifice Replacement
This unit uses orifice type LH32RFnnn (where “nnn” indicates
orifice reference size). When replacing unit orifices, order the
necessary parts through RCD. See Table 14 for available ori-
fice sizes. See Tables 15-17 for orifice sizes for natural gas and
liquid propane fuel usage at various elevations above sea level.
Ensure each replacement orifice is tight as its threads into the
manifold pipe and the orifice projection does not exceed maxi-
mum value. See Fig. 52.
See Table 18 for Low NOx usage at various elevations above
sea level.
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 firing
unit.
Table 12 — LED Error Code Description*
LED INDICATION ERROR CODE DESCRIPTION
ON Normal Operation
OFF Hardware Failure
1 Flash† Evaporator Fan On/Off Delay Modified
2 Flashes Limit Switch Fault
3 Flashes Flame Sense Fault
4 Flashes 4 Consecutive Limit Switch Faults
5 Flashes Ignition Lockout Fault
6 Flashes Induced-Draft Motor Fault
7 Flashes Rollout Switch Fault
8 Flashes Internal Control Fault
9 Flashes Software Lockout
LED — Light Emitting Diode
IMPORTANT: Refer to Tables 12 and 13 for additional trou-
bleshooting information.