Burner Ignition; Orifice Replacement - Carrier WeatherExpert 48LC 14 Series Service And Maintenance Instructions

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
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.
Table 9 — LED Error Code Description*
LED INDICATION
ON
OFF
2 Flashes
3 Flashes
4 Flashes
5 Flashes
6 Flashes
7 Flashes
8 Flashes
8 Flashes
LEGEND
LED — Light Emitting Diode
* 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.
/ -in. pipe fitting on the gas
1
8
ERROR CODE
DESCRIPTION
Normal Operation
Hardware Failure
Limit Switch Fault
Flame Sense Fault
4 Consecutive Limit Switch Faults
Ignition Lockout Fault
Induced-Draft Motor Fault
Rollout Switch Fault
Internal Control Fault
Software Lockout
IMPORTANT: Refer to Troubleshooting Tables 13 and 14 for
additional information.

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 10 — Orifice Sizes
ORIFICE
DRILL SIZE
#30
/
1
8
#31
#32
#33
#34
#35
#36
#37
#38
#39
#40
#41
#42
#43
#44
#45
#46
#47
#48
#49
#50
#51
#52
#53
#54
#55
#56
#57
#58
26
CARRIER DRILL
PART NUMBER DIA. (in.)
LH32RF129 0.1285
LH32RF125 0.1250
LH32RF120 0.1200
LH32RF116 0.1160
LH32RF113 0.1130
LH32RF111 0.1110
LH32RF110 0.1100
LH32RF105 0.1065
LH32RF104 0.1040
LH32RF102 0.1015
LH32RF103 0.0995
LH32RF098 0.0980
LH32RF096 0.0960
LH32RF094 0.0935
LH32RF089 0.0890
LH32RF086 0.0860
LH32RF082 0.0820
LH32RF080 0.0810
LH32RF079 0.0785
LH32RF076 0.0760
LH32RF073 0.0730
LH32RF070 0.0700
LH32RF067 0.0670
LH32RF065 0.0635
LH32RF060 0.0595
LH32RF055 0.0550
LH32RF052 0.0520
LH32RF047 0.0465
LH32RF043 0.0430
LH32RF042 0.0420