Nordyne furnace keeps running

[peacey]

I have a Nordyne M1Mb 056A BW and just recently replaced the thermostat, but when I did the furnace stays on after the click when it reaches temp. I reinstalled the old one, and it does the same thing. It comes on fine, then lights, then blows, when temp. is reached, it clicks at thermostat, then blows for minutes longer, then will shut off sometimes, or sometimes will just relight and come back on. Please help..thanx..

[Robert]

Hi,

You don't have a sequencer. Could be faulty ignition module or control board.


Would need to be able to test voltage to find problem or call an hvac tech to diagnose.


Start at gas valve and test for 24vac and work backwards following wiring diagram to locate where low voltage is remaining energized.



Thanks,
Robert

[peacey]

Thanks....However now I am getting a code 1 blink, for limit switch is open, how do I correct this????

[Robert]

Test to locate which limit is open. Then determine if furnace is overheating/HOT.

If so, call an hvac tech. If not (furnace has been on in long while for instance), replace limit.

Can give ordering info this evening if needed.



Thanks,
Robert