Trane furnace doesn't want to turn on

Mazeroth

One month into home ownership and my 20 year old Trane furnace decides it doesn't want to work. Joy. At first I thought it may be a bad thermostat (at least, I hoped it was) so I replaced it with an identical 20 year old Trane thermostat I took from our townhouse (replaced it with a Hunter digital but kept the original). No luck. I then reset the breaker twice which didn't do anything. I then decided to try to measure voltage on the four wires that go into the thermostat and I can't read a thing.

I talked to my Dad and he had me take the two doors off the front and open the black box that houses a transformer. That was a few minutes ago which was on his lunch break and he had to go. He said to try to read voltage on those wires to see if any of that is getting juice. I would measure at the breaker box but I don't want to have to open the whole thing up and potentially kill myself.

One nice thing, I think, is that our house came with a 1 year warranty. The downside is that we have to pay a $55 service fee for them to come check out the problem. I can understand why they do this as they would probably get 10x as many calls if they didn't have an upfront charge.

So, with that, can you guys suggest anything? I'll post back with what I find with the volt meter.

Thanks!

bigaudiofanatic

well no reply yeat u alright over there?

schwarcw

Electric? Gas? or Oil?

If it's a combustion unit, my guess is the fan limit switch. It it's electric, it's probably in the controls.

Sorry to hear of your woes Christian, good luck!

exalted512

I guess something can stop a trane.
-Cody

bigaudiofanatic

LOL I gues so or at least Mazeroth

Mazeroth

schwarcw wrote: »

Electric? Gas? or Oil?

If it's a combustion unit, my guess is the fan limit switch. It it's electric, it's probably in the controls.

Sorry to hear of your woes Christian, good luck!

It's natural gas. How do you fix a fan limit switch or is this something a tech will probably have to do?

Thanks.

EDIT: Yeah, I'm fine. I'm going to check it right now. Something else came up. I'll report back. Over!

dorokusai

You should measure voltage at the breaker box. Unless you have metal hands, and a overwhelming need to poke your fingers in things filled with electricity, instead of a VOM....you will be fine.

Just utilize caution.

If your getting voltage at the breaker but not at the unit, it's probably fused and they are blown.

Rivrrat

If you have a hot start ignitor (no pilot light) I'd start there. We went through three in nine yrs in our furnace in Seattle. I replaced two in our old gas oven that we just got rid of.

They don't last forever.

schwarcw

Mazeroth wrote: »

It's natural gas. How do you fix a fan limit switch or is this something a tech will probably have to do?

Thanks.

The sensor is in the flue box, electrics are mounted with the other controls. I replaced one when I moved into my first house. I can't remember how I diagnosed it.

Look Here

Carl

schwarcw

Rivrrat wrote: »

If you have a hot start ignitor (no pilot light) I'd start there.

Another high possibility.

Mazeroth

FIXED!

I got 120v on the wire coming in and then I saw something in front of me...a safety switch that unless depressed doesn't allow the furnace to kick on. When I was installing the new hot water tank and softener I remember taking the door off to look at the pilot and filters and I must not have put the door back on correctly. Sure enough, when I depressed the switch POOF, the gas ignited and the fan kicked on!

Thanks guys for all your help. Just goes to show how strong of a community we have here!

thejck

my next door neighbour had his furnace hooked up to a generator to heat his house during a long 10 day power outage and one evening it woudnt turn on the generator was running and other things were working but the generator would not turn on. it turned out to be the furnace was not getting enough apms from the generator so it was going into protect mode and not turning on. after letting it sit off for a while and turning off everything else hooked up to the generator the furnace started to kick back on.

Frank Z

I can understand why they do this as they would probably get 10x as many calls if they didn't have an upfront charge.

So very wrong. Who's going to pay the technicians wages, insurance, licensing fees, union dues (not a problem here), pay for the service van, the inventory in the van, the insurance for the van, the gas for the van, the maintennce for the van? Rent/mortgage for the shop/office space?

Would you expect a free visit to the doctors office anytime someone in your family felt ill? No? So why would I as an educated and highly skilled technician give you anything? I have a valuable skill that I busted by **** to get and I'll be damned if I give it away for nothing!

Not every service call turns a huge profit, sometimes you barely break even, and sometimes you lose money.


So here's your free service call...last one I'll ever do.
If there's no voltage at the thermostat, you may have one or more of the following problems:
1.) Bad Transformer
2.) Bad control fuse
3.) Tripped breaker
4.) Bad line voltage fuse
5.) Broken wire(s) or bad connection

thejck

watch out for those home warranties. those guys are weasels that will try to get away without doing any work if possible. once they are at your house they are already garunteed the 55 bucks and so it doesnt matter to them if they are not going to fix your problem. if they can find some excuse to get out of it they will use it. usually means something like
"oh this unit should be serviced every year. you dont have any records indicating that it was serviced last year so the home warranty doesnt cover it." or "the previous repairs were not carried out by a licenced professional and so the warranty doesnt cover that anymore"

Mazeroth

Whoa, whoa, whoa, Frank! You took what I said totally wrong, friend. What I said was I have a 1 year home warranty. I can understand why the warranty company charge a $55 fee to come look at the problem (under warranty) because if they didn't charge the $55 people would call and want things looked at constantly no matter how petty the problem. Then the cost of the warranty would probably quadruple.

Frank Z wrote: »

So very wrong. Who's going to pay the technicians wages, insurance, licensing fees, union dues (not a problem here), pay for the service van, the inventory in the van, the insurance for the van, the gas for the van, the maintennce for the van? Rent/mortgage for the shop/office space?

Would you expect a free visit to the doctors office anytime someone in your family felt ill? No? So why would I as an educated and highly skilled technician give you anything? I have a valuable skill that I busted by **** to get and I'll be damned if I give it away for nothing!

Not every service call turns a huge profit, sometimes you barely break even, and sometimes you lose money.


So here's your free service call...last one I'll ever do.
If there's no voltage at the thermostat, you may have one or more of the following problems:
1.) Bad Transformer
2.) Bad control fuse
3.) Tripped breaker
4.) Bad line voltage fuse
5.) Broken wire(s) or bad connection