Rheem Criterion II gas furnace -1 hour lockout, now what?

I have a Rheem Criterion II gas furnace. The unit starts and runs okay most of the time. However it will stop occasionally and will go into 1-hour lockout mode (based on light codes) . What is causing unit to work properly sometimes and not others?

I have checked the orange flame light. It appears to be on steady.

(When running) I went ahead and cleaned it as described. It is currently working but it’s hard to say if that is due to the handy work or just dumb luck.

Any other suggestions?

3 Answers

  • Anonymous
    1 month ago

    Is “1 hour lock out” the only description that it gives you? If it is, then it is probably flashing another code, as it is trying to work, then going into lockout. Make sure your air filter is clean and try cleaning the flame sensor. It is a thin metal rod in front of the far left burner. Clean it with some steel wool. Hopefully that will solve your problem.

  • Anonymous
    5 days ago

    The anticipator circuit in the thermostat is a 2 degree offset that is pretty much built into all stats. Generally, gas furnaces are designed to produce around 125 to 135 degree air, and cannot be :turned down”. This sounds to me like one of those situations where the unit is designed to produce too many BTU’s per hour. On the air conditioning side of it we would call it over sized. Thats when it removes too many BTU’s per hour and never really dries the air, just cools it. I suppose if you wanted to ultra customize this furnace, if the fan is a multi speed, a competent tech could switch the medium speed to a higher speed. That way the air would not be hanging around in the heat exchanger long enough to get 130 degrees. Now, on the cooling side, the speed would have to go up one notch too…. If the fan is not at least a two speed fan, That what I would do; change the fan motor to the next set of speeds.

  • Andrew B
    1 month ago

    If you cleaned the sensor and all has been well for the last couple days than you solved your problem. A furnace should be cleaned once a year regardless of its age. also change your filter monthly! would you let your car go with out an oil change? like i said preventive maintenance can save you huge repair costs later in life. Good luck my friend.

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