Any handymen in the house?

[SlowSpyder]

Our furnace has been acting strangely for the last couple of days. The furnace seems to run for a while, but then won't run when it's supposed to. This morning when we woke up the temp was 62 in the house, but the thermostat was set to 70. If we go and reset the power to the furnace it'll start up and run for a short while like normal and the temp will increase in the house. But, after a little while it'll shut off (almost always short of the temp set on the thermostat) and won't come back on like it's supposed to. It comes on enough to keep the house from absolutely freezing (like I said it was 62 this morning) but it never gets to temp either.

I know it's not that the furnace can't keep up with how cold it is outside, it would be running non-stop if that was the case, correct? It's that it won't kick back on. And, as I mentioned, if we reset the power to the furnace it seems to turn on for a while.

So far we've changed the air filter and made sure the intake on the outside of our home isn't blocked. Does anyone have any ideas what else I can check? Do furnaces have burn sensors/thermocouplers or anything? Any common things anyone can think of? The repair costs to have someone come here and fix it are pretty high, hopefully this is something easy. Thanks for any help, it is really appreciated.

*edit - We last had the unit serviced 10/04. This is what is on the receit, "serviced furnace, cleaned drain, cleaned intake, cleaned senser, checked safties and performance, changed pressure switch." Not sure if this will give anyone a clue as to what it could be. Thanks again.

 

[amdskip]

It may be the furnace thermocouple but I'm not an expert on this. My parents had to have theirs replaced on a 10 year old furnace. Is the furnace gas?

 

[SlowSpyder]

Originally posted by: amdskip
It may be the furnace thermocouple but I'm not an expert on this. My parents had to have theirs replaced on a 10 year old furnace. Is the furnace gas?

Yea, it is a natural gas furnace.

 

[Drako]

Is the power/error indicator blinking any pattern?

There is a little plastic window on the front of the unit that you can see through. You should see a red light in there. If it is blinking, a problem has been detected.

 

[Drako]

Here is a link to the service manual. It has the error codes in it, which you should have somewhere on your unit as well.

Service Manual

Hope this helps.

 

[SlowSpyder]

Thanks for the link.

I just took the condensation collector apart, the drain was backed up (I didn't even know furnaces had drains). We're testing it now to see what happens. <fingers crossed>

 

[Drako]

Good luck!

What was clogging the drain? The condensation should be pretty clean I would think.

 

[SlowSpyder]

I think that did it... thanks for the replies. Been running for close to an hour now without any issues. The water was backed up to the blower motor, lots came out when I disconnected the hose. The wife cleaned the condensor container, now we're golden. Thanks again.

 

[SlowSpyder]

Originally posted by: Drako
Good luck!

What was clogging the drain? The condensation should be pretty clean I would think.

Just dirt/sediment. Not sure where it came from, but I'd guess that a quart and a half of water poured out when I disconnected the hose. Still 70 in the house, so I think we're all good. Thanks again!

 

[Sluggo]

Originally posted by: SlowSpyder
Thanks for the link.

I just took the condensation collector apart, the drain was backed up (I didn't even know furnaces had drains). We're testing it now to see what happens. <fingers crossed>

Glad you got it running. The new high efficiency furnaces do have a condensation drain which was new to me as well. This quote I found explains it, for all the people who tell you that you are insane for telling them your furnace has a condensation drain.

Condensing gas furnaces are the most energy-efficient furnaces available, with seasonal efficiencies between 89 and 97 percent. Most have burners similar to conventional furnaces, with draft supplied by an induced draft fan. There are additional heat exchange surfaces made of corrosion-resistant materials (usually stainless steel) that extract most of the heat remaining in the combustion by-products before they are exhausted. In this condensing heat exchange section, the combustion gases are cooled to a point where the water vapor condenses, thus releasing additional heat into the home. The condensate is piped to a floor drain.