Furnace Questions

PineRidge · Dec 27, 2003

If you grasp the round painted ring on the round T87F Honeywell stat and gently pull it towards you it will pop off. The heat anticipator is the sliding scale on the bottom half of the stat. Look on the gas valve on the furnace and write down the amp draw to match it to the thermostat. The settings should be the same. If not gently realign the pointer within the T87F thermostat. The numbers are small and normally marked .4, .6, .8, etc. those are tenths not whole numbers

If the amp draw is already set correctly then you need to look elsewhere for the problem. When this furnace short cycles place your hand on the plenum or furnace bonnet (careful it may be real hot) and let me know if it is lukewarm or too hot to touch when the furnace is acting up..

TOMLESCOEQUIP · Dec 27, 2003

Well.........It's fixed now........In our large christmas gathering it appears that the kids knocked the cover of the t-stat ( throwing something) and trying to put the cover back on must have disturbed the setting on the cycling whachamacallit and got it screwed up. Thru trial & error ( mostly error) i now have a furnace that is more responsive than ever. I had it converted from LP to nat gas when they ran a line down our road 2 years ago, and when they (NOT ME ) changed the furnace over I don't think they ever readjusted the t-stat after changing the gas valve. THANK YOU !! for the wealth of information guy's............Saved me some $$$$ on this one.................TOM

PineRidge · Dec 27, 2003

Glad to help you Tom. That's what this site is all about. /forums/images/graemlins/grin.gif

TOMLESCOEQUIP · Dec 27, 2003

If you ever need to set the floats on a holley carb on your tri-power vette or rebuild the tilt cylinders on your forklift.......... call me !! I don't claim to know everything..........BUT I'll tell what I do know..........Just ask my wife .............Tom

boustany · Dec 29, 2003

I had exactly this problem with a high efficiency furnace.

I fought it for a while - it would work perfect if it hadn't run for a while (days), but once it was needed - on for a couple minutes, off for a while, etc., etc..

Then I though I heard funny gurgling sound one day ........

I noticed a black plastic sort of water hose about 1/2" diameter going into the fan housing. So I removed it an a quart of water poured out. It seems that the high efficiency furnaces condense water out of the output gasses. If the pipe is blocked they have a sensor which shuts off the burner.

So, the burner would run for a few minutes until the water got to the sensor. Then it would shut off. Then the water would slowly drip out and it could start again.

So I did the logical thing. I removed the hose and sucked/blew until the obstruction came out. Ever wonder what a bunch of dead bugs taste like? /forums/images/graemlins/tongue.gif

Anyway - problem solved. Hope it works for you!

Let us know in any event.

Oooooops. Guess I should have read all the posts. /forums/images/graemlins/blush.gif

Never mind!

TOMLESCOEQUIP · Dec 30, 2003

Hey......I'm just glad for all the help........my sensor didn't have any bugs but it was a little strange running the furnace while testing the vacumn sensor........use your imagination on that one !!...........TOM