# Comfortmaker Counterflow Furnace Problem



## woodbutcher (Dec 10, 2003)

Hey guys
I have an 1982 counterflow gas furnace in the shop that i'm havind a problem with and hope someone could help me out on what might be.
First off let me say that i'm a remodeling contractor and have been kicking around the trades for about 26 years. That being said, i've had occasian to do minor repairs on furnaces, though I have an HVAC contractor for most of the large projects. Unfortunatly he's also out of down till the first of the year.
Anyhow, the problem.
On call for heat everything works as it should, electronic ignition is immediate and so is the pilot flame. Thermal sensor is working as the gas valve opens after 40 seconds or so and the burners fire up.
Problem is that the burners will stay lit for about 5 to 6 seconds and there is an audioable click and the gas shuts down. After another 40 seconds or so the cycle starts over with the same results.
The system is really simple on this unit, basically the gas valve, spark ignitor and the limit switch. I have looked at the electrical schematic thinking ther was a secondary 'no flame' sensor but there is not.
I'm in the midst of assembling 775 square feet of laminate tops and the no furnace in the Chicago region is not going to work.
Any help would be appreciated.

Thanks


----------



## Bjd (Dec 19, 2003)

woodbutcher said:


> Hey guys
> I have an 1982 counterflow gas furnace in the shop that i'm havind a problem with and hope someone could help me out on what might be.
> First off let me say that i'm a remodeling contractor and have been kicking around the trades for about 26 years. That being said, i've had occasian to do minor repairs on furnaces, though I have an HVAC contractor for most of the large projects. Unfortunatly he's also out of down till the first of the year.
> Anyhow, the problem.
> ...


----------



## Guest (Feb 6, 2004)

*HVAC Contractor*

Is it 3 wire pilot burner?
Then check if yellow or green wire looses power(24V)
If green looses power then replace the pilot burner( green wire confirms existence of
pilot flame), if problem with yellow then check limit switch ( its better to bypass it for 
the time of troubleshooting, means short both terminals with jumper wire)
If there is no 24 V lost for all perid of time then replace the gas valve(also make sure
that 24 V is always present on gas valve).

Good luck
[email protected]


----------



## Steve Wiggins (Jan 17, 2004)

As your pilot burns against the flame proving mechanism it sucks in air to breathe. Any dirt in the air will start clogging up the air inlet and the pilot orfice. This makes the pilot flame weak and it won't prove flame.


----------



## mneff (Jun 26, 2010)

On call for heat everything works as it should, electronic ignition is immediate and so is the pilot flame. Thermal sensor is working as the gas valve opens after 40 seconds or so and the burners fire up.
Problem is that the burners will stay lit for about 5 to 6 seconds and there is an audioable click and the gas shuts down. After another 40 seconds or so the cycle starts over with the same results.

Here's the dope woodbutcher;

Your flame senoer is dirty scrpae it off , note do not use sand paper -- scrpe it like with a knoef balde, and that puppy will run like new-- hey have a great day! But just a word of advice stay to carpentry all of us know about this-- it;s basic , hope this was not for a paying client!


----------



## MAULEMALL (May 16, 2010)

7 year old thread ..:whistling


----------



## beenthere (Mar 5, 2009)

MAULEMALL said:


> 7 year old thread ..:whistling


He's a slow typer. :laughing:


----------

