Furnace question..........Churchmouse or anyone?

[CHCRandy]

My furnace is 12-15 years old....gas Trane XE80 and the wife just noticed it making a humming noise. I took the cover off and it was blinking 3 lights, which says "pressure switch problem". While I was looking at it they started flashing steady fast....and then furnace kicked on.

Seems to be functioning fine.......other than that hum. Any ideas?

Thanks

 

[DoggyDaddy]

It's old. It's probably just humming because it's forgotten the words.

 

[BigBoxaJunk]

Do you still have the manual for the furnace?

 

[churchmouse]

The humming could be the transformer getting angry. It could also have been the draft inducer motor. Hard to say but the pressure switch code is an indicator the motor on the inducer might be getting tired.
With out standing in front of it I am just throwing ideas out there.

 

[Informed Decision]

Where is the humming coming from.. The motor , through the ductwork & not able to locate,or elsewhere ? I used to have to oil my motor on my old furnace. Of course it needs to be removed for access to the plugs on the motor but after that it ran quiet for years. Actually better than my new one now. C.M. could probably put you in the right direction though.

 

[bocefus78]

The humming could be the transformer getting angry. It could also have been the draft inducer motor. Hard to say but the pressure switch code is an indicator the motor on the inducer might be getting tired.
With out standing in front of it I am just throwing ideas out there.

My Furnace is the same age and does the exact same thing. Last tech I had out (years ago) said it was the inducer motor. I primarily heat with wood so it didn't get fixed. Roughly a $300 repair IIRC. That was quoted....I didn't fix it. I Wanted a 2nd estimate. Can you give me a ballpark as to if this is a fair price? Not to hijack, but the OP may want to know as well.

Thanks.

 

[churchmouse]

My Furnace is the same age and does the exact same thing. Last tech I had out (years ago) said it was the inducer motor. I primarily heat with wood so it didn't get fixed. Roughly a $300 repair IIRC. That was quoted....I didn't fix it. I Wanted a 2nd estimate. Can you give me a ballpark as to if this is a fair price? Not to hijack, but the OP may want to know as well.

Thanks.

Make and model of your furnace. It does make a significant difference depending on where the parts are sold.
Also that price may well have doubled by now.

 

[CHCRandy]

I will try to see if I can find where the hum is coming from. It's not doing it now.......but I am sure it will come back.

It wasn't from the duct or the blower motor....and it quite once the draft fan came on and it fired up.

I think I just need to start looking into a new furnace.......do I have to replace C/A unit at same time as furnace?

Thanks guys.

 

[churchmouse]

I will try to see if I can find where the hum is coming from. It's not doing it now.......but I am sure it will come back.

It wasn't from the duct or the blower motor....and it quite once the draft fan came on and it fired up.

I think I just need to start looking into a new furnace.......do I have to replace C/A unit at same time as furnace?

Thanks guys.

If you A/C is the same age it might be to your benefit to do the entire system when you have the furnace out. It is so much easier and may save you some coin in the long run.
It would be no trouble to give it a look see and steer you down the right path. I look at 15 year old systems like a 150K vehicle. Might be OK today but trouble is right around the corner.

 

[sig-guy]

Trane/Am Std. are notorious for PS codes. Normally due to an intermittent PS failure. It might cause a problem today and never again for the rest of the season.

 

[sig-guy]

Can you give me a ballpark as to if this is a fair price? Not to hijack, but the OP may want to know as well.

Quoting an inducer replacement without make/model would be the same as giving a vehicle quote with no vehicle specs. The range really wouldn't help. Make/model would be needed to provide an accurate price.

 

[.356luger]

Some of the equipment i work on of that era is commercial but runs the system in a vaccume so basically if it failed the inducer runs for 90 min then board resets and tries 3 more times and repeat. Those pressure switches are cheap and I replace them everytime I get a code because its not worth a call back for a 20$ part that might not fail again for 2 weeks.

 

[wolfman]

I had trouble with pressure switch fault codes last winter. Found out that moisture was evaporating and leaving a deposit that plugged up the vac lines to the pressure switch. Reamed out the fitting, the pain in the A** one behind the inducer fan, and no more problems.

 

[churchmouse]

I had trouble with pressure switch fault codes last winter. Found out that moisture was evaporating and leaving a deposit that plugged up the vac lines to the pressure switch. Reamed out the fitting, the pain in the A** one behind the inducer fan, and no more problems.

Are you firing that furnace properly. Is it set for the right gas pressure at the burner rail. If it is low they will condensate to much and cause all kinds of issues including shortened life span.

 

[wolfman]

I had trouble with pressure switch fault codes last winter. Found out that moisture was evaporating and leaving a deposit that plugged up the vac lines to the pressure switch. Reamed out the fitting, the pain in the A** one behind the inducer fan, and no more problems.

Are you firing that furnace properly. Is it set for the right gas pressure at the burner rail. If it is low they will condensate to much and cause all kinds of issues including shortened life span.

Yup, have had it serviced by the company that installed it the last few years, and was told that this is known to happen occasionally.

 

[churchmouse]

Yup, have had it serviced by the company that installed it the last few years, and was told that this is known to happen occasionally.

Just asking. Might save some issues down the line.
Buddy had one installed by another friend and he set it up light on the firing rate. Furnace was done 10 years in.

 

[sig-guy]

Hey CM, the guys who want to sell furnaces don't pay no attention to the temp rise specs!

 

[ghitch75]

if your having water in the PS tube have your HVAC check the gas pressure......NG should be 7"WC and LP should be 14"WC delivery pressure and burner pressure should be 5"WC NG and 11"WC LP.......

low pressure will make a 80% sweat.......

 

[looney2ns]

I've been around the block a time or two over the years with different service techs while dealing with commercial buildings. I learned a lot by watching.
I think HVAC tech guys that really care and or really know what they are doing is very few and far between.
There is a large service co here that takes care of my BIL's equipment, he bragged on one guy that always came to do his twice yearly checkup. So I caved and called and asked for the same guy to check mine one year....yeah he was very personable and all that, but I noted a whole list of things he did not check while here. He basically just put a set of gauges on it and called it good. I called the co and raised a stink about his lack of doing his job and told my BIL he was a flippin knuckle head.

 

[sig-guy]

if your having water in the PS tube have your HVAC check the gas pressure......NG should be 7"WC and LP should be 14"WC delivery pressure and burner pressure should be 5"WC NG and 11"WC LP.......

low pressure will make a 80% sweat.......

If you're going to post about fuel pressures, I'd be nice if you post CORRECT information!

Normal input pressure for Nat is 5-7" wc with a 3.5" wc burner pressure.

Normal input pressure for LP is 11-14" wc with a 10" wc burner pressure.

**Always check equipment labels for the exact specs, as all equipment is not the same.

BTW, 80% don't sweat, a low temperature rise causes the flu gases to condense. Condensation can also destroy a high efficient furnace, when the condensation happens in the primary heat exchanger. Temperature rise specs are there to protect your equipment.