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Ducted gas hetaing keeps tripping the thermo fan switch. We seem to have plenty of air flow out of the vents and have replaced 75% of the ducting

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  • nitram divad Jul 25, 2008

    The Heater keeps cutting out. The thermo fan has a cut out swith which needs to be reset.

    The switch is a safety mechanism which prevents over heating. Therefotre lack of airflow over the override switch causes the heater to shout down.

    I have replaced a section of the air intake which had initially collapsed. I have also replaced 75% of the outlow ducting some of which had been crushed and may have lead to poor airflow. Once this was replaced the heater worked for a consistant five hours and now will not run for than 30secs


  • B Carson May 11, 2010

    Do you mean that the high limit switch keeps shutting off the gas and the fan keeps running? Do you mean the fan stops and the heater keeps running until the high limit switch shuts it down for safety reasons?



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It seems that you are saying the thermo fan stops first, thenfotre the safety limit switch shouts off the gas. This would mean the thermo fan motor is bad. It is overheating, which cuts out the thermo fan switch. The gas only shouts off because the thermo fan motor is bad.

Posted on Jul 25, 2008


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