26
9. Set room thermostat to call for low-stage heat. Adjust low-
stage pressure to specified setting.
10. Replace regulator cover screw(s) when finished.
11. With burner access panel removed, observe unit heating oper
-
ation in both high stage and low stage operation. Observe
burner flames to see if they are blue in appearance, and that
the flames are approximately the same for each burner.
12. Turn off unit, close manual gas shut off valve, remove pres
-
sure manometer and replace the
1
/
8
-in. pipe fitting on the gas
manifold. (See Fig. 34.)
Limit Switch
Remove blower access panel. Limit switch is located on the fan
deck. (See Fig. 29.)
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. 35.) The IGC contains a self-diagnostic
LED (light-emitting diode). A single LED (see Fig. 38) 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 9 for an explanation of LED error code descriptions. See
Table 11 for IGC connections.
If lockout occurs, unit may be reset by interrupting power supply
to unit for at least five seconds. See Fig. 39 for a typical IGC wir
-
ing diagram.
* 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 sequence.
Orifice Replacement
This unit uses orifice type LH32RFnnn (where nnn indicates ori
-
fice reference size). When replacing unit orifices, order the neces
-
sary parts via Carrier RCD. See Table 10 for available orifice siz
-
es. See Table 12 for orifice sizes for Natural Gas and LP fuel usage
at various elevations above sea level. Check that each replacement
orifice is tight at its threads into the manifold pipe and that orifice
projection does not exceed maximum value. (See Fig. 33.)
Table 9 — LED Error Code Description*
LED INDICATION
ERROR CODE
DESCRIPTION
ON
Normal Operation
OFF
Hardware Failure
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
8 Flashes
Software Lockout
LEGEND
LED
— Light Emitting Diode
IMPORTANT: Refer to Troubleshooting Tables 13 and 14 for
additional information.
Table 10 — Orifice Sizes
ORIFICE
DRILL SIZE
CARRIER
PART NUMBER
DRILL
DIA. (in.)
#30
LH32RF129
0.1285
1
/
8
LH32RF125
0.1250
#31
LH32RF120
0.1200
#32
LH32RF116
0.1160
#33
LH32RF113
0.1130
#34
LH32RF111
0.1110
#35
LH32RF110
0.1100
#36
LH32RF105
0.1065
#37
LH32RF104
0.1040
#38
LH32RF102
0.1015
#39
LH32RF103
0.0995
#40
LH32RF098
0.0980
#41
LH32RF096
0.0960
#42
LH32RF094
0.0935
#43
LH32RF089
0.0890
#44
LH32RF086
0.0860
#45
LH32RF082
0.0820
#46
LH32RF080
0.0810
#47
LH32RF079
0.0785
#48
LH32RF076
0.0760
#49
LH32RF073
0.0730
#50
LH32RF070
0.0700
#51
LH32RF067
0.0670
#52
LH32RF065
0.0635
#53
LH32RF060
0.0595
#54
LH32RF055
0.0550
#55
LH32RF052
0.0520
#56
LH32RF047
0.0465
#57
LH32RF043
0.0430
#58
LH32RF042
0.0420
