Service/Status Code Instructions - ICP 9MAC/E series Troubleshooting Manual

Variable speed, modulating electronic condensing four-way multipoise gas furnace

Table of Contents

If status code recall is needed disconnect the "R" thermostat lead, reset power, and put setup switch "SW1-1" in the ON position. To clear the status

code history put setup switch "SW1-1" in the ON position and jumper thermostat terminals "R", "W/W1", and "Y/Y2" simultaneously until the

Heartbeat flashes.

LED CODE

CONTINUOUS OFF -

Check 115 VAC at L1 and L2, 24 VAC at SEC-1 and SEC-2, and 24V fuse.

HEARTBEAT -

(bright-dim-bright-dim) Control has 24 VAC power.

ON SOLID -

The control is locked out and will auto reset after 1 hour. Lockout could be due to any of the following:

Reset power to clear lockout. Replace control if status code repeats.

EACH OF THE FOLLOWING STATUS CODES IS A SINGLE OR TWO DIGIT NUMBER WITH THE FIRST NUMBER DETERMINED

BY THE NUMBER OF SHORT FLASHES AND THE SECOND NUMBER AFTER THE (+) SIGN IS THE NUMBER OF LONG

FLASHES.

PRESSURE SWITCH DID NOT OPEN – Check for:

Obstructed pressure tubing.

Pressure switch stuck closed.

LOW PRESSURE SWITCH DID NOT CLOSE OR REOPENED – Indicates the low pressure switch input failed to close on a call for

heat, or opened during minimum-heat. If opens during blower on-delay period, blower will come on for the selected blower off-delay. If

opens within 5 minutes after ignition the next heating cycle will be restricted to maximum-heat. Check for:

Proper vent sizing.

Air leak between vestibule and blower compartment.

Restricted vent.

Plugged condensate drain.

Low inlet gas pressure (if LGPS used).

Excessive wind. If problem persists turn setup switch "SW1-3" ON to boost inducer speed.

Improper pressure switch wiring.

Failed or "Out-of-Calibration" pressure switches.

Water in vent piping, possible sagging pipe.

Disconnected or obstructed pressure tubing.

LIMIT CIRCUIT FAULT – Indicates the limit, or flame rollout is open or the furnace is operating in maximum-heat only mode due to 2

successive limit trips while operating at any rate less than or equal to 71% of maximum rate. Blower will run at intermediate heat airflow

for 4 minutes or until open switch remakes whichever is longer. If open longer than 3 minutes, code changes to lockout #7. If open less

than 3 minutes status code #4 continues to flash until blower shuts off. Flame rollout switch requires manual reset. Check for:

Loose blower wheel.

Defective switch or connections.

Improper minimum- or maximum-heat gas input adjustment.

Dirty filter or restricted duct system.

Improper limit switch or no limit gasket.

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.

IGNITION PROVING FAILURE – Control will try three more times before lockout #6 + 1 occurs. If flame signal is lost during blower

on-delay period, blower will come on for the selected blower off-delay. Check for:

Low inlet gas pressure.

Control ground continuity.

Gas valve defective or turned off.

Defective Hot Surface Igniter.

Manual valve shut off.

Oxide buildup on flame sensor (clean with fine steel wool).

Proper flame sense micro amps (.5 micro amps DC min., 4.0 – 6.0 nominal).

Green/Yellow wire MUST be connected to furnace sheet metal.

Inadequate flame carryover or rough ignition.

Flame sensor must not be grounded.

LIMIT CIRCUIT LOCKOUT – Lockout occurs if the limit, or flame rollout switch is open longer than 3 minutes or 10 successive limit

trips occurred during maximum-heat. Control will auto reset after 3 hours. Refer to status code #4.