Instruction manual

80
Is 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 door switch closed?
Is circuit breaker closed?
Check for continuity in wire from circuit breaker to furnace.
Close circuit breaker and go back to START.
Is 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.
Is 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?
To recall status code briefly remove and reconnect one RED wire from the draft safeguard switch to display stored status code. You can also recall the previous status code by momentarily shorting the TEST/TWIN terminal to Com24V terminal until the LED goes out. LED will flash the status code of the previous fault or status code #11 (1 short and 1 long flash) if there was no previous fault. 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 FAN speed (when equipped) 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 other than #11?
Go to section below for the status code that was flashed.
Does the control respond to W, Y1 (if present), Y/Y2, and G (24V) thermostat signals?
Run system through a heating or cooling cycle to check operation. Status codes are erased after 72 hours.
Is 24V present at W, Y1 (if present), Y/Y2 or G thermostat terminals on the furnace control?
Check room thermostat or interconnecting cable.
Disconnect all the thermostat wires from the furnace control.
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
NO
YES
YES
YES
YES
YES
YES
YES
YES
YES
START
YES
YES
NO
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NO
Troubleshooting Guide
A11622
Fig. 64 -- Troubleshooting Guide
59SC2A