So I had a client do a home inspection on a place they just put in escrow. Inspector found some rust inside the furnace – it’s a Trane high-efficiency unit, about 15 years old. Pic attached – sorry for the
#160;
There was no apparent source or sign of leakage above (or below). Any thoughts on what might’ve caused this?
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photo shows nothing. Is the rust just a coating or is the box rusted thru between burner and plenum? Where is the furnace located? Here, the ones in damp cellars only last about 15 years.
Some rust is normal because combustion byproduct is water and some acids and carbon. But when the rust goes thru to the plenum, the unit is blowing some CO toxin into the living space
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photo shows nothing.
Nothing at all? Or just "not enough info?" If you can't see anything at all, scroll right and down. It's just a big photo. Otherwise I can re-take later today as I'll be back there.
Is the rust just a coating
Looks to be. Some rust on the box, and the gas supply pipe immediately above it. It certainly isn't rusted out or anything like that.
or is the box rusted thru between burner and plenum?
According to the inspector he couldn't get in to see much, as it's all sealed up. Imagine an HVAC company will need to be called - the sellers had the furnace "serviced" recently, but who knows what they actually did. I always like an unbiased second opinion, though. : )
That said, this was the only rust visible when the front panel was removed. No other spots, hard water deposits, or suchlike.
Where is the furnace located? Here, the ones in damp cellars only last about 15 years.
It's in a basement. It's pretty remarkable, actually - 100-year old house, brick foundation, dry as a bone. Not even damp or smelly, and it poured rain here this morning. Surprised the heck outta me. A lot of those foundations around here are in less-than-great shape.
All I see in the photo is the ?thermocouple valve and line. Background is entirely black.inspectors often note minor things with a "should be inspected/tested by a licensed professional technician" esp with things they don't understand but that could be life threatening.otherwise known as CYA.service generally means clean or replace the burner nozzle and adjust the mix, vacumn up. Some companies do cheack for cracks and rust out on every call, some just look when indications warrant. call the company that just serviced it and ask. They might assure you, might do a free re-inspect to cover their butts, or might do nothing.
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inspectors often note minor things with a "should be inspected/tested by a licensed professional technician" esp with things they don't understand but that could be life threatening.
otherwise known as CYA.
Yeah, I know - I've seen plenty of that in 6-1/2 years. There's lots of CYA in real estate. : ) It did seem a bit weird though, thus the posting here. Like I said - if a better pic would help, I'd be glad to provide one. It wasn't an especially well-lit spot, I didn't have a propert flashlight, and no real camera. Pretty much a recipe for miserable photo quality.
I couldn't see it well enough eitherBtw: HI's a generalists - maybe it looks like CYA, but it's what we are paid for.too easily overdone, of course.
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I knowq that. Didn't mean it to sound negative, just statement of fact that is at least 50% likely to explain this
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Very tough to say based on the photo.
It would appear that there is a drip above the gas pipe.
I formed this theory based on the apparent drip trail down the side of the pipe.
Water (I'm guessing, condensation from combustion) drips onto gas pipe and then onto the top of the electrical box below - causes rust in both places.
Is the flue inlet directly above this pipe / box? - Likely suspect. Would be dry if unit was not running. Has the cap blown off of the flue allowing rainwater to travel down the flue?
Option #2: Does this furnace also house an A/C coil and act as an air handler for the A/C? If yes, there could be a pinhole in the pan for the condensate from A/C.
That's all I can guess about that.....
Jim
He said it was a high efficiency unit.
Flue gass is ussually pretty cool by the time it enters the pipe. My gues would be the condensate trap has a leaking fitting. Most just use pinch type clamps on the hoses. After serviceing the trap, the clamp wasn't properly set back on the hose or the hose was split when it was pulled off to blow out the trap and then the calmp put back on in hopes it wouldn't leak. I've also seen the traps clogged up, but that generally shuts a hi-eff furnace down.
The other possibilty is the A-coil condensate pan or drain has scumed up and dripped down on the gas regulator/valve.
Probably a better guess than mine!
But we are on the same page - namely, water is (or was) dripping on that gas pipe which was not immediately evident when the inspection was done - would need to run it and watch to find out more.
A plumb bob hung above the rust spot on the pipe might help locate the source......
JimNever underestimate the value of a sharp pencil or good light.
Jason, Since your is a hi eff. it would not have a standing pilot, but what I have learned over the years over the years.
Appliances that have a pilot, keep lit in the off seasons, if in a basement.
Helps keep the unit dryer, esp. in a damp location.
Never vent cloth dryer directly into basement. Some people think the added heat & humidity is great in the winter time, but creates problems, surface rust!!
Dosen't address your problem directly but related, kinda sorta.
This was suppose to be to David.I agree. It is dripping water from above. Not caused by normal condensation.Either it just started or it was found and corrected or it is very minor.Besides what you mentioned there might be a short section of the tubing to the A coil that is exposed and collecting condensation..
William the Geezer, the sequel to Billy the Kid - Shoe
Edited 10/2/2009 1:24 pm by BillHartmann
Bill,
I could see a thing in that photo, My ex in laws were all in the heating business, and those were some of the pet peeves I have learned from them.
There appears to be some very slight corrosion on the painted steel box below the valve assembly. If that's what you're talking about it's pretty normal for a furnace in a basement. It occurs due to condensation during non-heating season, especially if the AC is running (using the furnace air handler).