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HVAC Guru
HVAC Guru, HVAC TECH
Category: HVAC
Satisfied Customers: 14007
Experience:  15yrs in the HVAC industry with certificates and degrees.
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I have a lennox m/n ghr26q4/5-120--8 furnace and it will

Customer Question

I have a lennox m/n ghr26q4/5-120--8 furnace and it will light at times then when it goes to light again it may or may not when i turn the power off to the unit and try restart it will most times
the code idicates flame sensed without gas valve energized so i cleaned the flame sensor but i also notice the cooling fan will not shut off even after a considerable time even hours
i thought perhaps a block outlet pipe but it was not
now i have determined the board is faulty because it continues to tell the fan to blow and even if i disconnect the wires to the fan and reconnect it comes back on the only way to shut it down is to cut the main power and then it seems to reset the board
am i on the right track
Submitted: 1 year ago.
Category: HVAC
Expert:  HVAC Guru replied 1 year ago.

Hello and thanks for using this service, if you have been waiting do not worry or get upset I am just one of the techs on here and I try to get to as many customers as I can and I just picked up your question now. Please give me time to respond as typing, researching and adding links takes me time to do so please be patient and often I will ask you questions to narrow down the issue to get is diagnosed correctly.

Expert:  HVAC Guru replied 1 year ago.

Typically when you get a code of flame sensed without the gas valve energized on that unit the board is bad. The boards would often fail and then basically the computer is messing up seeing inputs that are not there. BAsed on what you have stated and since it is a Lennox GHR26 series this is going to be a bad board. It was so common they have revised it here is a link to the part

CLICK HERE

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