Heating, Air Conditioning, Fridge, HVAC/American Standard Error Codes


We have an American Standard Freedom 90 furnace with problems on first use this heating season. The control board blinks 3 times in sequence, which would indicate a problem with intake/exhaust air restriction or a bad pressure sensor (per another web site). The gas never starts to flow, and the ignitor never goes on. There is no restriction in the air flow to/from the furnace.

The AC was replaced this summer. The furnace blower starts when the exhaust blower starts; it shouldn't start until the heat exchanger has reached its operating temperature range. The service tech said it looks like the control board went bad. I wondered if it may be related to the AC replacement.

Does American Standard publish documentation of the error codes and the circuit board wiring diagram, so I can check that the replacement wiring was done to the correct terminals?

Hi Brian,

The equipment manufacturers make it very difficult to get this info. When looking for info include the model number. Some times this works. Have you checked the inside of the furnace covers for wiring diagrams?

Replacing the AC should not effect the wiring in the furnace. If the blower and the combustion fan comes on at the same time, yes I would think the module is bad.

Heating, Air Conditioning, Fridge, HVAC

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Jim S.


I can answer questions on gas or electric furnaces, ac units and heat pumps. I don't work on boilers,chillers,or home appliances.


I have been in the HVAC trade for over 35 years. For the past 15 years I have owned my own business. I am semi-retired so I can answer questions in a timely manner.

I attended trade school for 5 years on weekends and evenings. This was very hard to do, but well worth it!

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