American Standard Furnace Error Codes

Error code in RACE? 3

I have an American Standard Freedom 95 modulator with a link to the ACOT900 thermostat attached. Apparently the red acot900 LED is lit with error code 26 error 26 on the control panel. I haven't found the model yet. This happens by accident when the warm-up program is activated. I tried to run a race in the heat of the day, but it didn't help. Error can occur 23 times in each heating program.

I also cleaned the filter to see if it was different, no. At the same time, it means that I turn off the power and restart the system, it does not improve the situation.

I found that error 26 is a height limit error in the document, but what is the upper limit? What else can I check?

update

I can add this detail based on the answer given.

Race always shows error message. It sounds high (not high) for about 30 seconds, then returns to normal and resumes normal operation as if nothing had happened.

And the desired temperature never reached the end of the program.

Check the chimney for obstruction.

The upper limit switch is on the heat exchanger and opens when the temperature is high. The switch can be turned off normally in 2 poles / lowers the temperature of the heat exchanger by closing the circuit in the upper DP without relay.

I would like to check the motor amperage first and on all SDs if it is not generating enough amperage. Then check the gas pressure, position and flame of the stove. Well, basically you are calling someone to make a service call.

These codes are pretty stupid. The upper limit is the temperature switch that will turn off the device due to poor air flow. Register closed, filter, overheating and shutting down, wrong time, vapor coil, full of dirt.

Also, if you have one of these PITA electronic modulators, you may have a very expensive problem that will cause this problem. Good with modulation system and savings promised by seller. Unless the part is under warranty, you have lost 8 years of gas savings.

American Standard Furnace Error Codes

If the fan is on, but nothing turns it on or off, as other posters suggest, it's probably a button. The pressure switch detects when the ventilation is blocked. Turn off the power supply first. The chimney has a drain pipe that draws thick water out of the chimney. Located at a lower point near the fan motor for support. Remove the hose and replace the hose if water leaks from the vent. If water does not come out, take one end of the hanger or similar, and slide the pipe into the vent to see if it is closed. If so, take the water out of the bowl and let it drain. If the block is missing, follow the instructions and repeat the steps. It is usually trapped at the point where the leg protrudes from the face. Remove from the water in the sink, shake and rinse. Check holes when not in use, making sure there are no nests or obstructions. That's all you can do safely, but it's usually a thick net.
It's been a safe journey ever since we got the problem fixed. If it's really high, it's an error code. Basically they told me it was the wrong finance module.
American Standard / Train has a newsletter on it. The module has been changed.

American Standard Furnace Error Codes