Carrier 4-WAY MULTIPOISE FIXED-CAPACITY DIRECT-VENT CONDENSING GAS FURNACE 58MXA - Manual (Page 13)

Is circuit breaker closed? Close door switch and go to start.
Is red LED status light on?
Is door switch closed?
Is red LED status light blinking rapidly without a pause?
Is there 1
15v going to switch?
Replace door switch.
Replace control center
.
Replace transformer
.
Is red 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. Check for previous fault by momentarily shorting the
TEST
terminal and the C terminal until the LED goes out. LED will flash the status code of any previous fault or the code No. 1
1
(1 short
and 1 long flash) if no previous fault.
After the control repeats the
code 3 times, the control will go through a brief component test sequence.
The inducer will start
and run for the entire component test.
The HSI, blower motor heat
speed, and blower motor cool speed will run for 10-15 sec each.
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
,
Y
,
or G 24-vac thermostat signals? Run system through a heating or cooling cycle to check operation. Status codes are erased after 48 hrs or whenever power (1
15v
or 24v) is interrupted.
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
,
Y
, or G
terminals on the control? Replace control if it does not respond to 24-vac signal at W
,
Y
,
or G screw terminals. Check room thermostat or interconnecting cable.
YES NO
NO
→
Troubleshooting
Guide
13