Lennox Residential Furnace Problem

Buz Roberts

I have a Lennox model 80MGF4X-75A-5 forced air furnace as original equipment in my new 1996 condo. It just started acting up. It's problem I believe is the spark unit or more likely the high tension voltage. When the thermostat is turned up the small blower comes on as normal and a minute or so later I hear the gas valve (Honeywell VR8205) relay click and the hiss of gas. I never hear the click of the electronic ignition so the gas valves closes and the cycle is repeated 3 times before it gives up. Do I need to replace the entire circuit board that provides the high tension voltage and if so can I source that somewhere other than a Lennox repairman coming to the house?

I am new to this forum so forgive me if this subject is not appropriate here and thanks in advance for the help.

Regards, Buz Roberts

southern CA

Glen

S8600 series

Short answer - yes replace the ignition module - Honeywell makes a universal control that can be substituted for the Lennox unit.

Unknown

Buz, if you have power to the

ignition module and no spark out then it is typically a new board. You could also have the igniter circuit grounded out somewhere. What is the make of module on the unit and maybe some numbers on the board?

If you want to take a chance on it being the board give it a shot. I would however really advise getting a professional to take a look at the furnace. While you have them looking at it asked them to give it a combustion test to insure yours and your families safety. It should be checked once a year.

RichW

I'm not a Lennox expert.But, I think the 80MGF has a Lennox only circuit board that controls everything on the furnace. You can only get the parts from a Lennox dealer/supplier.
Translation:you need a pro for this.
Good luck.

[Deleted User]

Boards

Lennox has (as usual) issued a new board for that furnace due to problems with the original. If it is original series, I would advise a technician as there is some rewiring to do on this unit.

Gas fired equipment is something where what you don't know CAN kill you.

Mike

Buz Roberts

Thanks much for everyone's input!

I'm having a pro come out to repair and do a combustion check as suggested. I'm in southern CA and thought you'd like to know the rates. They are $89.00 for the first half hour and $24.00 for every quarter hour after that. Wish me luck and thanks again for all the quick and pertinent responses. I love this website and will tell all my friends.

Tim Schram

Lennox

Buz,

This unit has a lennox only circuit board and cannot be replaced with a universal. I believe also that this series had issues with the ignition wire and an update kit is available. The short term fix is to pull the ignition wire off of the "nail" style connector on the board and trim it back about an inch, and reconnect it. Get a professional to come out with the updated ignition wire and see from there. I have seen this misdiagnosed many times as a board failure.

Tim

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Buz Roberts

Tim,

The professional came out before I got your response and in less than 10 seconds he did exactly what your message stated, pulled the wire out trimmed it and stuck it back in. That was the complete fix! $90 later he was gone.

I appreciate your response and will highly recommend this site to all my do-it-yourselfer friends.