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WIRING DIAGRAMS
Refer to Fig. 6 and 7 for wiring diagrams.
TROUBLESHOOTING
Refer to the service label. (See Fig. 9—Service Label.)
The Troubleshooting Guide following Fig. 9 can be a useful tool
in isolating furnace operation problems. Beginning with the word
“Start,” answer each question and follow the appropriate arrow to
the next item.
The Guide will help to identify the problem or failed component.
After replacing any component, verify correct operation sequence.
Fig. 9—Service Label
A00286
LED CODE
If status code recall is needed, briefly remove then reconnect one main limit wire to display stored status code.
SERVICE
To initiate the component test sequence, shut OFF the room thermostat or disconnect the "R" thermostat lead.
Briefly short the TEST/TWIN terminal to the "Com 24V" terminal. Status LED will flash code and then turn ON the
inducer motor at high speed until the end of the test, then shift to low speed for 10 seconds. The hot surface ignitor,
blower motor low-heat speed, blower motor high-heat speed, and blower motor cool speed will be turned ON for
10-15 seconds each. Gas Valve and Humidifier will not be turned on.
326379-101 REV. A (lit-top)
CONTINUOUS OFF
- Check for 115VAC at L1 and L2, and 24VAC at SEC-1 and SEC-2.
CONTINUOUS ON
- Control has 24VAC power.
RAPID FLASHING
- Line voltage (115VAC) polarity reversed. If twinned, refer to twinning kit instructions.
EACH OF THE FOLLOWING STATUS CODES IS A TWO DIGIT NUMBER WITH THE FIRST DIGIT DETERMINED BY THE
NUMBER OF SHORT FLASHES AND THE SECOND DIGIT BY THE NUMBER OF LONG FLASHES.
STATUS
COMPONENT TEST
11 NO PREVIOUS CODE
- Stored status codes are erased automatically after 72 hours.
12 BLOWER ON AFTER POWER UP
(115 VAC or 24 VAC) -Blower runs for 90 seconds, if unit is powered
up during a call for heat (R-W closed).
13 LIMIT, DRAFT SAFEGUARD, FLAME ROLL-OUT SWITCH OR BLOCKED VENT SWITCH
(when used)
LOCKOUT
- Control will auto reset after three hours. Reset switch. Refer to #33.
14 IGNITION LOCKOUT -
Control will auto-reset after three hours. Refer to #34.
21 GAS HEATING LOCKOUT
- Control will NOT auto reset.
Check for: - Mis-wired gas valve - Defective control (valve relay)
22 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
23 PRESSURE SWITCH DID NOT OPEN
Check for:
- Obstructed pressure tubing.
- Pressure switch stuck closed.
24 SECONDARY VOLTAGE FUSE IS OPEN
Check for: - Short circuit in secondary voltage (24VAC) wiring.
31 HIGH-HEAT PRESSURE SWITCH OR RELAY DID NOT CLOSE OR REOPENED
Check for: Control relay may be defective - Refer to #32
32 LOW-HEAT PRESSURE SWITCH DID NOT CLOSE OR REOPENED
If open longer than five minutes,
inducer shuts off for 15 minutes before retry. Check for: - Proper vent sizing
- Defective inducer motor
- Disconnected or obstructed pressure tubing
- Excessive wind
- Defective pressure switch
- Restricted vent
- Inadequate combustion air supply
- Low inducer voltage (115VAC) if code flashes while unit runs in low-heat with high speed inducer.
If it opens after trial for ignition period, blower will come on for 90 second recycle delay.
33 LIMIT, DRAFT SAFEGUARD, FLAME ROLL-OUT SWITCH OR BLOCKED VENT SWITCH
(when used)
LOCKOUT IS OPEN
- If open longer than three minutes, code changes to #13. Flame roll-out switch requires
manual reset. Check for:
- Defective blower motor or capacitor.
- Dirty filter or restricted duct system. - Restricted vent
- Loose blower wheel.
- Defective switch or connections.
- Proper vent sizing
- Excessive wind
- Inadequate combustion air supply (Flame Roll-out Switch open).
- Open Flame Roll-out switch. Manual reset or replace.
34 IGNITION PROVING FAILURE
- Control will try three more times before lockout #14 occurs. If flame signal
lost after trial for ignition period, blower will come on for 90 second recycle delay. Check for:
- Oxide buildup on flame sensor (clean with fine steel wool).
- Proper flame sense microamps (.5 microamps D.C. min., 4.0 - 6.0 nominal).
- Gas valve defective or gas valve turned off.
- Defective Hot Surface Ignitor
- Manual valve shut-off.
- Low inlet gas pressure.
- Control ground continuity
- Inadequate flame carryover or rough ignition. - Flame sensor must be ungrounded.
- Green/Yellow wire
MUST
be connected to furnace sheet metal.
43 LOW-HEAT PRESSURE SWITCH OPEN WHILE HIGH-HEAT PRESSURE SWITCH IS CLOSED
Check for:
- Pressure switch stuck open - Disconnected or obstructed pressure tubing
45 CONTROL CIRCUITRY LOCKOUT
Auto-reset after one hour lockout due to;
- Flame sense circuit failure - Software check error - Gas valve relay stuck open
Reset power to clear lockout. Replace control if status code repeats.
A00286
9