Carrier 48VL-E Installation Instructions Manual page 34

48VL-(E, F): Installation Instructions
SYMPTOM
Burners will not ignite
Inadequate heating
SYMPTOM
No Power or Hardware failure
(LED OFF)
Check fuse, low voltage circuit
(LED 1 flash)
Limit switch faults
(LED 2 flashes)
Flame sense fault
(LED 3 flashes)
4 consecutive limit switch faults
(LED 4 flashes)
Ignition lockout fault
(LED 5 flashes)
Pressure Switch fault
(LED 6 flashes)
Rollout Switch fault (Standard and Low
NOx models)
Burner Thermal Switch fault (Ultra Low
NOx)
(LED 7 flashes)
Internal control fault
(LED 8 flashes)
1
Temporary 1 hr auto reset
(LED 9 flashes)
: If the IGC must be replaced, be sure to ground yourself to dissipate any electrical charge that my be present before handling new control board. The IGC is sensitive to static
*WARNING
electricity and my be damaged if the necessary precautions are not taken.
IMPORTANT: Refer to Table 15-Troubleshooting Guide-Heating for additional troubleshooting analysis.
LEGEND
IGC—Integrated Gas Unit Controller
LED—Light-Emitting Diode
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Table 14 – Troubleshooting Guide–Heating
CAUSE
Water in gas line
No power to furnace
No 24-v power supply to control circuit
Mis-wired or loose connections
Misaligned spark electrodes
No gas at main burners
Dirty air filter
Gas input to furnace too low
Unit undersized for application
Restricted airflow
Limit switch cycles main burners
Table 15 – Troubleshooting Guide–LED Status Codes
CAUSE
Loss of power to control module (IGC)*.
Fuse is blown or missing or short circuit in
secondary (24VAC) wiring.
High temperature limit switch is open.
The IGC* sensed flame that should not be
present.
Inadequate airflow to unit.
Unit unsuccessfully attempted ignition for 15
minutes.
Open pressure switch.
Rollout switch has opened.
Microprocessor has sensed an error in the
software or hardware.
Electrical interference impeding IGC software
Drain. Install drip leg.
Check power supply fuses, wiring or circuit breaker.
Check transformer.
NOTE: Some transformers have internal over-current protection
that requires a cool-down period to reset.
Check all wiring and wire nut connections
Check flame ignition and sense electrode positioning.
Adjust as necessary.
1. Check gas line for air. Purge as necessary. NOTE: After
purging gas line of air, wait at least 5 minutes for any gas to
dissipate before attempting to light unit.
2. Check gas valve.
Clean or replace filter as necessary
Check gas pressure at manifold match with that on unit
nameplate
Replace with proper unit or add additional unit
Clean or replace filter. Remove any restriction.
Check rotation of blower, temperature rise of unit. Adjust as
necessary.
Check 5-amp fuse son IGC*, power to unit, 24-v circuit
breaker, and transformer. Units without a 24-v circuit breaker
have an internal overload in the 24-v transformer. If the
overload trips, allow 10 minutes for automatic reset.
Replace fuse if needed. Verify no short circuit in low voltage
(24 VAC wiring).
Check the operation of the indoor (evaporator) fan motor.
Ensure that the supply-air temperature rise is in accordance
with the range on the unit nameplate. Clean or replace filters.
Reset unit. If problem persists, replace control board.
Check the operation of the indoor (evaporator) fan motor and
that supply-air temperature rise agrees with range on unit
nameplate information.
Check ignitor and flame sensor electrode spacing, gaps, etc.
Ensure that fame sense and ignition wires are properly
terminated. Verify that unit is obtaining proper amount of gas.
Verify wiring connections to pressure switch and inducer
motor. Verify pressure switch hose is tightly connected to
both inducer housing and pressure switch. Verify inducer
wheel is properly attached to inducer motor shaft. Verify
inducer motor shaft is turning.
Rollout switch will automatically reset, but IGC* will continue
to lockout unit. Check gas valve operation. Ensure that
induced-draft blower wheel is properly secured to motor
shaft. Reset unit at unit disconnect.
If error code is not cleared by resetting unit power, replace
the IGC*.
Reset 24-v. to control board or turn thermostat off, then on
again. Fault will automatically reset itself in one (1) hour.
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REMEDY
REMEDY