Lennox Control Board Issue?

An area where professionals can discuss HVAC /R related issues and topics.

Moderator: juster

Post Reply
Posts: 1
Joined: Mon Jan 23, 2012 9:29 pm

Lennox Control Board Issue?

Post by Jonrob » Mon Jan 23, 2012 9:43 pm

Hi there,

Went to a service call Sunday evening to Lennox 90G... Furnace. As soon as stat calls for heat, induced draft motor comes on, however NO low voltage is being sent to any of my safeties or gas valve. Nothing at pressure switch, roll out... nothing. Almost instantly, control board clicks and turns my blower motor on, still no 24 V at anything, and the board tells me its normal operation. Transformer is fine, stats calling properly... all is good. Thus, changed board. Now, stat still calls and sends 24, blower motor comes on until delay finishes, and ventor motor does nothing. It came on once for a fluke 20 seconds, but even still none of my 24V controls were getting power, even when ventor motor comes on. Frustrating because Lennox doesn't do after hours tech help. Is it possible I got a bum control board out of the box, or do you have any suggestions?

Thanks a lot for the help.

Most Valued Contributor
Posts: 542
Joined: Wed Jul 06, 2011 9:10 am

- Lennox Control Board Issue?

Post by heatseeker » Tue Jan 24, 2012 3:10 pm

chances are you did or are doing something wrong. You could have damaged control board or maybe misplaced a wire trace thru it one wire at a time. How did you know the last circuit board was failed.?

Regular Contributor
Posts: 13
Joined: Wed Mar 28, 2012 7:07 pm

- Lennox Control Board Issue?

Post by Big » Wed Mar 28, 2012 7:18 pm

Lennox has many problems with their boards , even the new ones.Get another board.

Post Reply