Electrostatic Discharge (ESD)
NOTE: Discharge static electricity accumulated in the body
before touching the unit. An electrostatic discharge can adversely
affect electrical components.
Use the following steps during furnace installations and servicing
to avoid damage to the integrated control module. By putting the
furnace, the control and the person at the same electrostatic
potential, these steps will help avoid exposing the integrated
control module to electrostatic discharge. This procedure is
applicable to both installed and non installed (ungrounded)
1. Disconnect all power to the furnace.
NOTE: Do not touch the integrated control module or any
wire connected to the control prior to discharging your body's
electrostatic charge to ground.
2. Firmly touch a clean, unpainted, metal surface of the furnace
away from the control. Any tools held in a person's hand
during grounding will be discharged also.
3. Service the integrated control module or connecting wiring
after following the discharge process in Step 2.
NOTE: Do not recharge your body with static electricity by
moving or shuffling your feet or touching ungrounded
objects. If you touch an ungrounded object, repeat Step 2
before touching the control or wires.
4. Follow steps 1 through 3 before removing a new control from
its container or installing the control on a furnace. Return any
old or new controls to their containers before touching any
The ignition control is equipped with a momentary pushbutton
switch that can be used to display the last 6 faults on the dual
7-segment LED display. The control must be in Standby Mode
(no thermostat inputs) to use the feature. Depress the switch for
approximately 2 seconds. Release the switch when the LED
display is turned off. The last 6 faults will be displayed most
recent to least recent on the dual 7-segment LED display.
NOTE: Consecutively repeated faults are stored a maximum of
3 times. For example, a clogged return air filter causes the
furnace limit to trip repeatedly. The control will only store this fault
the first 3 consecutive times the fault occurs.
Resetting from Lockout
Furnace lockout results when a furnace is unable to achieve
ignition after 3 attempts during a single call for heat. It is
characterized by a nonfunctioning furnace and a "E0" code
displayed on the dual 7-segment display. If the furnace is in
"lockout," it will (or can be) reset in any of the following ways.
1. Automatic reset. The integrated control module will
automatically reset itself and attempt to resume normal
operations following a 1-hour lockout period.
2. Manual power interruption. Interrupt 115-volt power to the
3. Manual thermostat cycle. Lower the thermostat so that there
is no longer a call for heat for 1 to 20 seconds, and then reset
to previous setting.
NOTE: If the condition which originally caused the lockout still
exists, the control will return to lockout. Refer to the "Diagnostic
O P Normal operation
E 0 Lockout due to excessive retries
E 1 Low-stage pressure switch stuck closed at start of heating
E 2 Low-stage pressure switch stuck open
E 3 Open high-limit switch
E 4 Flame detected when no flame should be present
E 5 Open fuse
E 6 Low flame signal
E 7 Igniter fault or improper grounding
E 8 High-stage pressure switch stuck closed at start of heating
E 9 High-stage pressure switch stuck open
E A Reversed 115 VAC polarity
d 0 Data not yet on network
d 4 Invalid memory card data
b 0 Blower motor not running
b 1 Blower communication error
b 2 Blower HP mismatch
b 3 Blower motor operating in power, temperature or speed
b 4 Blower motor current trip or lost rotor
b 5 Blower motor locked rotor
b 6 Over/under voltage trip or over temperature trip
b 7 Incomplete parameters sent to motor
b 9 Low indoor airflow
C 1 Low-stage cooling
C 2 High-stage cooling
L O Low-stage heat
F Continuous fan
1 2 CFM/100; Alternates with C1, C2, LO, HI, F
Internal control fault/no power