A00231a
Is circuit breaker closed?
Close door switch and go to start.
Is LED status light on?
Is door switch closed?
Is LED status light blinking
rapidly without a pause?
Is there 1
15v going to switch?
Replace door switch.
Replace control center
.
Replace transformer
.
Is LED status light blinking
ON/OFF slowly with a
combination of short and long
flashes?
Check for correct line voltage
polarity
. If units are twinned,
check for proper low-voltage
(24v) transformer phasing.
To
recall status code br
iefly remo
ve
then reconnect one
RED wire from the Dr
aft Saf
eguard Switch to displa
y stored
status code
. Y
ou can also recall the pre
vious status code by
momentarily shorting the
TEST/TWIN terminal and the
COM24V terminal until the LED goes out. LED will flash the
status code of the previous f
ault or the code No. 1
1 (1 shor
t
and 1 long flash) if no previous f
ault.
After the control
repeats the code 4 times, the control will go through a brief
component test sequence.
The inducer will star
t at high
speed and run for the entire component test then shift to
lo
w speed f
or 10 seconds
. The HSI, b
lo
w
er motor lo
w-heat
speed, blower motor high-heat speed, and blower motor
cool speed will run for 10-15 sec each.
Gas v
alv
e and
humidifier will not be tur
ned on.
Determine status code.
The
status code is a 2 digit number
with the first digit determined by
the number of short flashes and
the second digit by the number of
long flashes.
W
as there a previous fault code
other than No. 1
1?
Does control respond to
W/W1,
W2,
Y1,
Y/Y2, or G 24-vac thermostat signals?
Run system through a lo
w-heat, high-heat
or cooling cycle to check operation.
Status
codes are erased after 72 hrs
.
Go to section with status code
determined.
Is there 1
15v at L1 and L2?
Close circuit breaker and go back to start.
Check for continuity in wire from circuit breaker to furnace.
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
NO
NO
YES
YES
YES
ST
AR
T
Is there 24v at SEC-1 and SEC-2?
NO
Is 24 vac present at
W/W1,
W2,
Y1,
Y/Y2, or G terminals on the control?
Replace control if it does not respond to 24-vac signal at
W/W1,
W2,
Y1,
Y/Y2, or G screw terminals.
Check room thermostat or interconnecting cable.
YES
NO
NO
Tr
oub
leshooting Guide
10
