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Johnnyv84 01-25-2013 12:39 PM

Furnace is not coming on right away, or at all
So up to a few days ago my furnace was working perfectly fine until my wife asked me to up the heat a few degree's. As soon as i did that it all went to ****. The thermostat would call for heat but it wouldn't kick on till it was around 15 celcius, then it would come on and go to about 22 celcius (where i had it set too). Sometimes it just wouldn't come on at all until i cycled the power, even then sometimes id have to do it multiple times before it would come on.

So i went out and bought a new thermostat and everything seemed to be working fine again for 2 days. Again i come home from work, wife says is cold, i up it a couple degree's and bam, starts doing the same crap all over again.

Sometimes it would work perfectly fine, other times it wouldn't kick on at all until i restart the power, and other times it wouldn't come on till it got really cold. And when it WAS working (like last night before i went to bed) i let it go, went to bed, woke up in the morning, wasn't working again.

So i tried swapping to another new thermostat i had, did the same thing. So i put it back to the better new one i bought, still wouldn't work. Set the temp to 22 celcius on hold, thermostat read 18 in the house, wouldn't kick on. 25 min or so later when it got to around 15 celcius, furnace finally kicked on.

Anybody have any idea as to whats going on and what it might cost to fix? my wife called her furnace guy that she knows and he's coming out today to look at it (guarenteed the thing is gonna work and make a liar out of me though). But does anyone have any idea what it could be and what kind of $$$ il be looking at to fix it?


Edit: We even tried constantly upping the temperature and waiting a few minutes to see if the furnace would kick itself on and nope. We had it up to like 25 celcius and it read 17, but still wouldn't kick on even though you could see the thermostat calling for heat to come on.

jagans 01-25-2013 12:52 PM

Is this a condensing furnace?

Johnnyv84 01-25-2013 12:53 PM

Natural gas high efficiency furnace

jagans 01-25-2013 02:41 PM

It sounds to me like when you raise the temperature the furnace starts producing more condensate than its drainage system can handle, then the draft system gets messed up.

Open the bottom door. take off the trap and flush it with bleach and soapy water. Make sure all drainage lines are clear suck out the large line from the secondary heat exchanger with your shop vac, them remove the clamps and soak the drain line in soapy water and bleach.

Check your intake and exhaust pipes, Probably 3 inch PVC and make sure they are clear Shop Vac.

Make sure vacuum lines and protrusions on vacuum switch are clear. Clear Small black vacuum tubes.

Make sure evaporator coil and filters are clean.

Then try furnace again.

If you send picture we can point out items.

Johnnyv84 01-25-2013 03:12 PM

Well my wife called a repair man and he showed up pretty quickly. Just waiting on the verdict to see what he has found out.

Johnnyv84 01-25-2013 04:01 PM

Ok repair men left and apparently they said it was extremely clogged. All the hoses and the condensate (im assuming the lil box that pumps out all the water from condensation). Said it was the worst they have ever seen. Cleaned up everything and unclogged all the hoses, and turned it on and off at the furnace and all was good. They didn't try the thermostat at all but they said it should be fine.

My wife has been reporting to me that its working so.... i guess we shall see. I still would have liked them to play with the thermostat at least to test it out after all said and done, but my wife said they just told her what they did , said it should be fine, left a bill and walked out

So when i get home im gonna put it into programmed mode instead of hold mode and see what happens. If it still isn't working il be calling them back and being like "wtf, why didn't you test it at the thermostat?"

jagans 01-25-2013 05:53 PM

What your furnace was doing indicated clogged condensate lines. Have you ever serviced it yourself? Dont feel bad, I did the same thing. Figured all I had to do was change filters till I found water running out the bottom of the furnace, then I dug into it, and got myself educated on how these HE Condensing furnaces work.

There are guys on this site that really know their stuff vis a vis HVAC. Im not one of them, but your problem sounded pretty obvious to me.

When it gets tough, you will need Doc, Yuri, Been there, and the other folks.
They can get down to problems related to specific models.

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