Carrier 48LC Series Controls, Start-Up, Operation And Troubleshooting page 42

1 FLASH - INDOOR FAN DELAY
MODIFIED (HEATING)
2 FLASHES - OPENING OF LIMIT
SWITCH
3 FLASHES - FLAME SENSOR
INDICATES FLAME WITH
CLOSED GAS VALVE
4 FLASHES - LIMIT SWITCH
CYCLED 4 TIMES ON SINGLE
CALL FOR HEAT
5 FLASHES - IGNITION LOCKOUT
(No ignition within 15 minutes)
6 FLASHES - INDUCED DRAFT
MOTOR FAULT
(No signal from the Flue Gas
Pressure Switch or 60 seconds)
7 FLASHES - OPENING OF
ROLLOUT SWITCH
8 FLASHES - HARDWARE OR
SOFTWARE FAULT
9 FLASHES - SOFTWARE
LOCKOUT
No
LEGEND
IDM – Induced-Draft Motor
IGC – Integrated Gas Unit Controller
NOTE: Thermostat Fan Switch in the
"AUTO" position.
FLASHING
IGC HIGH VOLTAGE
TRANSFORMER CREATES A
10,000 VOLT SPARK FOR 5
SECONDS
IGC SAFETY LOGIC WILL SHUT
OFF GAS VALVE AND SPARK
20 SECOND PURGE OF HEAT
EXCHANGER
IS THIS THE
33RD RETRY? (OR 15
MINUTES)
Yes
IGNITION LOCKOUT
(5 FLASHES OF LED)
(DELAY EXTENDED BY 5 SECONDS FOR EACH LIMIT SWITCH TRIP
Fig. 24 - - IGC Service Analysis Logic
OFF
LED is
ON
CALL FOR
'W1' FROM BASE CONTROL BOARD ENERGIZES 'W'
ON IGC - 1 MINUTE LOCK-ON
COMBUSTION RELAY ON IGC IN ENERGIZED
COMBUSTION RELAY ENERGIZES INDUCED DRAFT MOTOR (IDM) THROUGH
TERMINAL 'CM' ON IGC
IF IDM IS TURNING AT CORRECT SPEED (AT LEAST 2400 RPM), FLUE GAS
PRESSUE SWITCH SENDS CORRECT SIGNAL TO TERMINAL 'J1' ON IGC
IF LIMIT SWITCH AND ROLLOUT
SWITCH ARE CLOSED, IGC SAFETY
LOGIC WILL INITIATE IGNITION
SEQUENCE
DOES IGC DETECT
No
.2 MICROAMPS FOR 2
SECONDS
Yes
AFTER 45 SECONDS (OR LESS IF THE TIMING
HAS BEEN REDUCED DUE TO LIMIT SWITCH
TRIPS) IGC WILL ENERGIZE BLOWER RELAY
DID LIMIT
SWITCH OPEN BEFORE THE 45
SECONDS (OR THE MODIFIED
TIME) HAS TIMED OUT?
No
NORMAL HEATING OPERATION
HEATING DEMAND SATISFIED
IDM STOPS, SAFETY LOGIC SHUTS OFF GAS VALVE
45 SECOND BLOWER SHUTOFF DELAY
MAXIMUM DELAY: 3 MINUTES)
42
24 VOLTS
BETWEEN YES
F1 AND C
No
1. BLOWN 5 AMP FUSE
2. DEFECTIVE 24V TRANS.
3. BROKEN WIRE
4. NO POWER TO UNIT
HEATING
IGC SAFETY LOGIC OPENS GAS
VALVE FOR 5 SECONDS
SUBTRACT 5 SECONDS FROM
Yes
INDOOR FAN ON TIME DELAY
DEFECTIVE
IGC BOARD
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