A02350a
Troubleshooting Guide – Variable Speed
START
Is AMBER LED status light on?
Is there 24V at SEC-1 and SEC-2?
Is there 115V at L1 and L2?
Replace furnace control.
Is door switch closed?
Replace transformer.
Replace door switch.
Is there 115V going to switch? Is circuit breaker closed?
NO
YES
YES
Check for continuity in wire from circuit
breaker to furnace.
Close circuit breaker and go back to
START.
Is AMBER LED status light blinking
rapidly without a pause?
Check for correct line voltage polarity. If
units are twinned, check for proper low-
voltage (24V) transformer phasing.
YES
NO
YES
Is AMBER LED status light blinking
ON/OFF slowly with a combination of
short and long flashes?
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?
NO
YES
To recall previous status codes disconnect the R
thermostat connection, reset power, and put setup
switch SW1-1 in the ON position. The AMBER LED
will flash the status codes in the order of occurrence.
Record status codes until status code #11 flashes (1
short and 1 long flash). After status code #11
flashes the status codes will repeat. Status codes
are erased after 72 hours or can be manually erased
by putting setup switch SW1-1 in the ON position
and jumpering R, W/W1, and Y/Y2 simultaneously
until status code #11 is flashed. When done put
setup switch SW1-1 in the OFF position.
Was there a previous status code other
than #11?
Go to section below for the status code
that was flashed.
NOYES
Does the control respond to W/W1, W2,
Y1, Y/Y2, and G (24V) thermostat
signals?
Run system through a low-heat, high-
heat, or cooling cycle to check operation.
Status codes are erased after 72 hours
or can be manually erased by putting
setup switch SW1-1 in the ON position
and jumpering R, W/W1, and Y/Y2
simultaneously until status code #11 is
flashed.
NO
Is 24V present at W/W1, W2, Y1, Y/Y2 or
G thermostat terminals on the furnace
control?
Disconnect all the thermostat wires from
the furnace control.
YES
Does the problem repeat when using a
jumper wire?
Replace furnace control.
The thermostat is not compatible with the
furnace control. Either install a ballast
resistor, connect the Com24V thermostat
terminal to the thermostat, or replace the
thermostat.
YES
YES
Check room thermostat or
interconnecting cable.
Close door switch.
NO NO NO
YES
NO NO
YES YES
NO
NO
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