ICM Controls ICM2811 Installation, Operation & Application Manual page 3

To service control, and prior to disconnection, label all wires.
Failure to do so may result in wiring errors which can cause dangerous operation.
1. Turn thermostat to OFF position or set it to the lowest possible
setting.
2. Turn OFF electrical supply to furnace.
Failure to turn off gas and electric supplies can result in explosion, fire,death, or personal injury.
6. Disconnect thermostat wires and humidifier wires (if equipped
with a humidifier).
7. Disconnect line voltage, blower, electronic air cleaner wires (if
equipped), and transformer wires.
8. Remove wiring harness from circuit board.
9. Remove screws or any other fasteners and old circuit board.
1. Ground yourself properly before installing the new ICM2811 control board.
2. Mount the new control using any screws and fasteners previously removed.
3. Connect all line/low voltage, accessory, thermostat and ground wires.
4. Verify the sequence of operation.
LED
Status Description
ON Normal operation
OFF Control board failure
1 Ignition failure (soft
lockout)
2 Pressure switch stuck
closed
3 Pressure switch stuck
open
4
Limit switch fault
5 Flame out of sequence
6 Roll out switch fault
7 Weak flame
8 Miswired gas valve
9
Unused
10 Hot and neutral reversed
11 Brownout
12 Twinning fault
Remove Existing Control
CAUTION!
CAUTION!
Install New Control
LED Fault Codes
Check for proper input voltage and check the fuse; if not resolved replace control.
Clean or replace flame sensor, check igniter for proper operation & input voltage, check the
transformer's common is grounded to earth ground.
Check for contaminated or defective pressure switch.
Check for obstructed pressure switch tubing or defective pressure switch. Check for oxidation
on terminals, broken wires, or defective inducer motor .
Checked for blocked airflow, blocked ductwork, and dirty filter. Check or replace high limit
switch if defective.
Check for intermittent or defective gas valve and check for dirty or defective flame sensor.
Check for a cracked heat exchanger, defective rollout switch , broken wires on the roll out
switch, or replace roll out switch if required.
Weak flame is caused by carbon build up on the flame sensor, poor grounds, or improper
placement of flame sensor . Clean or replace flame sensor, reassure grounds, ensure flame
sensor is fully enveloped in the flame.
Check for shorted or mis-wired gas valve, check harness wires for any shorts or breaks, and
check the pressure switch for proper operation.
N/A
Check for proper polarity of incoming voltage on the primary and secondary of the transformer.
A brownout fault indicates a low voltage condition. Check the voltage on the primary and
secondary of the transformer and ensure there is no excessive load on the transformer.
Ensure the common of both step down transformers are connected together and grounded to
earth ground. Ensure there is a ground wire connecting the chassis of both furnaces. Verify
there is a twinning wire connected from the twin terminal on furnace one to the twin terminal on
furnace two.
3. Turn OFF gas supply to furnace.
4. Remove furnace blower and control access doors.
5. Remove control box cover.
10. Examine control and control box to check for water
stains.
11. Make repairs if any sources of water leakage are found.
Be sure to check humidifiers, evaporator coils, and vent
systems in the area of the control.
Trouble Shooting Tips