Troubleshooting Guide - Carrier 58MSA Service And Maintenance Instructions

START
NO
Is LED status light on?
YES
YES
Is LED status light blinking rapidly without a
pause?
NO
NO
Is LED status light blinking ON/OFF slowly
with a combination of short and long flashes?
YES
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?
YES
Go to section below for the status code that
was flashed.

TROUBLESHOOTING GUIDE

NO
Is there 115V at L1 and L2?
YES
NO
Is there 24V at SEC-1 and SEC-2?
YES
Replace furnace control.
Check for correct line voltage polarity. If units
are twinned, check for proper low-voltage
(24V) transformer phasing.
To recall status code briefly remove and reconnect one RED wire from the Limit
Switch or Flame Rollout switch to display stored status code. On RED LED
control do not remove power or blower access panel before initiating status
code recall. Shorting the TEST/TWIN terminal to Com24V terminal until the
LED goes out will flash status code #11 (1 short and 1 long flash). After the
control repeats the code 4 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 COOL speed will run for 10 – 15
seconds each. Gas valve and humidifier will not be turned on.
Was there a previous status code NO
other than #11?
NO
Is door switch closed?
YES
NO
Is there 115V going to switch?
YES
Replace door switch.
Replace transformer.
NO
Does the control respond to W, Y1 (if present),
Y/Y2, and G (24V) thermostat signals?
YES
Run system through a heating or cooling cycle
to check operation. Status codes are erased
after 72 hours. On RED LED boards stored
status codes can also be erased whenever
(115V or 24V) is interrupted.
YES
Replace furnace control.
Close door switch and go back to START.
Is circuit breaker closed?
YES
NO
Check for continuity in wire from circuit breaker
to furnace.
Close circuit breaker and go back to START.
Check room thermostat or
interconnecting cable.
NO
Is 24V present at W, Y1 (if present), Y/Y2 or
G thermostat terminals on the furnace control?
YES
Disconnect all the thermostat wires from the
furnace control.
Does the problem repeat when using
a jumper wire?
NO
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.
A02214a