Wiring Diagrams; Troubleshooting - Carrier 100 Series Service And Maintenance Procedures Manual

If status code recall is needed, briefly remove then reconnect one main limit wire to display stored status code.
LED CODE
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 r eversed. 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.
11 NO PREVIOUS CODE - Stored status codes are erased automatically after 72 hours.
12 BLOWER ON AFTER POWER UP (115 VAC or 24 VAC)
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
Check for: - Mis-wired gas valve
22 ABNORMAL FLAME-PROVING SIGNAL - Flame is proved while gas valve is de-energized. Inducer will run
until fault is cleared. Check for:
23 PRESSURE SWITCH DID NOT OPEN
- Obstructed pressure tubing.
24 SECONDARY VOLTA GE FUSE IS OPEN Check for:
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
- Excessive wind
- Restricted vent
- 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:
- Dirty filter or restricted duct system.
- Loose blower wheel.
- Proper vent sizing
- Inadequate combustion air supply (Flame Roll-out Switch open).
- Open Flame Roll-out switch. Manual reset or replace.
34 IGNITION PROVING FAILURE
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
- Low inlet gas pressure.
- Inadequate flame carryover or rough ignition.
- 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:
45 CONTROL CIRCUITRY LOCKOUT Auto-reset after one hour lockout due to;
- Flame sense circuit failure
Reset power to clear lockout. Replace control if status code repeats.
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.

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.
SERVICE
STATUS
- Control will NOT auto reset.
- Defective control (valve relay)
- Leaky gas valve
Check for:
- Pressure switch stuck closed.
- Defective blower motor or capacitor.
- Restricted vent
- Defective switch or connections.
- Excessive wind
- Control will try three more times before lockout #14 occurs. If flame signal
- Pressure switch stuck open
- Software check error
COMPONENT TEST
Fig. 9—Service Label
-Blower runs for 90 seconds, if unit is powered
-Stuck-open gas valve
- Short circuit in secondary voltage (24VAC) wiring.
- Disconnected or obstructed pressure tubing
- Defective pressure switch
- Inadequate combustion air supply
- Manual valve shut-off.
- Control ground continuity
- Flame sensor must be ungrounded.
- Disconnected or obstructed pressure tubing
- Gas valve relay stuck open
326379-101 REV. A (lit-top)
The Guide will help to identify the problem or failed component.
After replacing any component, verify correct operation sequence.
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