Fig. 10—Service Label
A99149
SERVICE
11
12
13
14
21
22
23
24
31
32
33
34
43
45
LED CODE
STATUS
COMPONENT TEST
HUM
G
R
Y/Y2
W/W1
C
W2
OM
24 V
LED
TWIN
TEST
123
4
OF
F
If status code recall is needed, do not remove power or blower door. Briefly remove and
then reconnect one main limit wire to display stored status code.
NO PREVIOUS CODE - Stored status codes are erased when power
(115VAC or 24VAC) to control is interrupted or 48 hours after each fault is cleared.
BLOWER ON AFTER POWER UP (115VAC or 24 VAC) - Blower runs for 90 seconds,
if unit is powered up during a call for heat (R-W closed).
LIMIT OR FLAME ROLL-OUT SWITCH LOCKOUT - Control will auto reset after three
hours. Reset switch or replace fuse link. Refer to #33
IGNITION LOCKOUT - Control will auto-reset after three hours. Refer to #34
GAS HEATING LOCKOUT - Control will NOT auto-reset.
Check for:
- Mis-wired gas valve
- Defective control (valve relay)
ABNORMAL FLAME-PROVING SIGNAL - Flame is proved while gas valve is
de-energized. Inducer will run until fault is cleared.
Check for:
- Leaky gas valve
- Stuck-open gas valve
PRESSURE SWITCH DID NOT OPEN Check for:
- Obstructed pressure tubing
- Pressure switch stuck closed.
SECONDARY VOLTAGE FUSE IS OPEN
Check for: - Short-circuit in secondary voltage (24VAC) wiring
HIGH-HEAT PRESSURE SWITCH OR RELAY DID NOT CLOSE OR REOPENED
Check for: - Control relay may be defective
- Refer to #32
LOW HEAT PRESSURE, DRAFT SAFEGUARD, AUX-LIMIT (when used*) SWITCH DID NOT
CLOSE OR REOPENED (DOWNFLOW ONLY*) If open longer than five minutes,
inducer shuts off for 15 minutes before retry. Check for:
- Proper vent sizing
- Low inducer voltage (115VAC)
- Defective Blower motor or capacitor
- Defective inducer motor
- Defective pressure switch
- Restricted vent
- Inadequate combustion air supply
- Excessive wind
- Disconnected or obstructed pressure tubing If it opens after trial for ignition
period, blower will come on for 90 second recycle delay.
LIMIT OR FLAME ROLL-OUT SWITCH IS OPEN - If open longer than three
minutes, code changes to #13. Flame roll-out switch requires manual reset.
Check for: - Dirty filter or restricted duct system. - Loose blower wheel.
- Defective blower motor or capacitor.
- Defective switch or connections.
- Inadequate combustion air supply (Flame Roll-out Switch or fuse link open).
- Open Flame Roll-out switch, or fuse link. Manual reset or replace.
IGNITION PROVING FAILURE - Control will try three more times before lockout #14
occurs. If flame signal is lost after trial for ignition period, blower will come on for
90 second recycle delay. Check for: - Gas valve defective or gas valve turned off.
- Oxide buildup on flame sensor (clean with fine steel wool).
- Proper flame sense microamps (.5 microamps D.C. min., 4.0 - 6.0 nominal in
HIGH HEAT). - Green wire MUST be connected to furnace sheet metal.
- Flame sensor must be ungrounded.
- Manual valve shut-off.
- Defective Hot Surface Ignitor
- Control ground continuity.
- Inadequate flame carryover or rough ignition. - Low inlet gas pressure.
LOW-HEAT PRESSURE, DRAFT SAFEGUARD, OR AUXILIARY LIMIT (when used*) SWITCH
OPEN WHILE HIGH HEAT PRESSURE SWITCH IS CLOSED Check for:
- Disconnected or obstructed pressure tubing
- Pressure switch stuck open
- Refer to #32 and #33
REPLACE CONTROL
EACH OF THE FOLLOWING STATUS CODES IS A TWO-DIGIT NUMBER WITH THE FIRST DIGIT DE-
TERMINED BY THE NUMBER OF SHORT FLASHES AND THE SECOND DIGIT BY THE NUMBER OF
LONG FLASHES.
CONTINUOUS OFF - Check for 115VAC at L1 and L2, and 24VAC at SEC1 and SEC2.
CONTINUOUS ON -
Control has 24VAC power.
RAPID FLASHING -
Line voltage (115VAC) polarity reversed. If twinned, refer to
twining kit instructions.
To initiate the component test sequence, shut "OFF" the room thermostat or
disconnect the "R" thermostat lead. Briefly short TWIN/TEST terminal to
"Com 24 V" Terminal. Status LED will turn off, control will turn "ON" the inducer motor-
low speed, inducer motor-high speed, hot surface ignitor, blower motor-low gas
heat speed, blower motor-high gas heat speed and blower motor-high cool
speed for 7-15 seconds each. Gas valve and humidifier will not be turned on.
320893-101 REV. D (LIT)
*
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