strong odor from furnace

[options]

Homeowner has a 2 year old high efficiency Carrier GFA w/air and a very strong odor coming from the supply side of the system when the heat is on. They state that they heard a loud noise from the furnace and began to smell this odor shortly thereafter. The noise has since gone away, but the smell hasn't. Coil, pan and humdifier water panel are clean. To me, it smells like some type of chemical. I was in the home for an hour and experienced some irritation to the eyes and respiratory tract. Coil was fitted properly and there are no openings around it for anything to have fallen thru to the heat exchanger. Any suggestions?

Thank you

[Edited by options on 11-22-2004 at 05:20 PM]

[jacob perkins]

An insulation burning smell?
That's probably burning insulation.

[Hroper]

Check the vents on the furnace and anything else they have that uses fuel. Have they done and staining or polyuratane, do they have A GAS STOVE OR DRYER. Burning eyes don't sound good.

[hvac-learning]

is the duct work and supply plenum lined on the inside? is the cooling coil leaking refrigerant?

[options]

The furnace is vented thru pvc. No lining in either the plenum or the ductwork and it doesn't have any burnt odor to it. It appears to be localized to the supply side of the furnace and is at its strongest coming out of the two closest vents upstairs. This is a small home and the odor quickly spreads throughout. I did detect a slight odor near the outside, bottom rear of the blower cabinet, but hadn't checked there before the furnace had been fired. I'm not positive, but I believe that all other appliances in the home are electric. The furnace sits on a carpeted concrete floor. I checked for possible moisture in the flooring, walls and ceiling with a Tramex Leak Seeker.

They had used 9-D-9 on a moisture problem in an adjacent room, but its odor is very different from this. They also said that they had used a drain opener in the laundry tubs a few days before and had forgotten about it, leaving it there for app. 4 hours before rinsing it out. Those tubs are 12' from the furnace and there is no apparent odor near either of them or the 4" drain they're piped into. They denied doing any type of staining or painting, etc. for the past several months. I also checked for open and leaking containers, but found no sign of any, nor are there any stored chemicals or storage areas near any of the returns.

I had suggested that it might be a freon leak (refrigerant oil?), but their heating contractor is telling them that freon has no odor. I've never applied heat to freon, so I can't argue with this claim. Their contractor also said that he thinks this is likely to be dirty sock syndrome, and that he would clean the coil. I've smelled DSS before and this isn't anything like it.

[coolwhip]

Maybe one of the installers dropped something in the heat exchanger. Like some pvc or the furnace manual.

[hvac-learning]

lower back of cabinet? is the secindary heat exchanger located in that area? pull the blower wheel to check maybe it has a small leak.

[rimek]

I think the insulation referred to was the cabinet insulation around the heat-x.
What does puron cooking smell like :)- seriously, you should recommend a search, remove blower and look up, access heat-x from above and search - the usual routine. It won't be fast and easy, but how much time will you save guessing- if the heating contractor told them something- then that contractor knows about this and is offering no solutions? Are you the owner? Is this 2 yr old carrier a puron install? THAT would be interesting!

[Wild Leg]

Originally posted by options


...I had suggested that it might be a freon leak (refrigerant oil?), but their heating contractor is telling them that freon has no odor. I've never applied heat to freon, so I can't argue with this claim....


R-22 has little or no odor, UNTIL heated.
However, it produces a very distinctive, toxic odor when burned. It irritates the eyes & respiratory tract.
The temperatures in a gas furnace are high enough to cause it to burn into phosgene gas.
Phosgene gas was used as a chemical weapon in WWI (mustard gas?). Low exposure can cause irritation, but high levels cause fluid to collect in the lungs, possibly resulting in fatality.

[trane]

If its still working then I don't know but the run capacitor might have blew or the transformer. Good Luck

[options]

Initial problem was thought to be mold related and I was called in by their heating contractor to inspect and clean the affected portions of the system.

I've asked the homeowner to view this thread.

Thank you for your replies.

[hvac-learning]

puron does have a smell when it get hot the same as all refrigerants do. remember they are a chemical compound. and when they burn/ or get too hot they release an oder. worth a check. at least you will make an effort and not say its a dds. that for those who feel they don`t have the time to do a proper investigation.

[condenseddave]

If it's a refrigerant leak, it'll stop as soon as it's leaked out. Shouldn't take too long.

Hard to believe it would be refrigerant, though. The coil would be after the Heatx, and when the blower started, would dissipate anything in there pretty quick.

[jdenyer]

Could be cracked or leaking heat exchanger, I know Nox which is produced during high temperature combustion has a faint acidic odor that is irritating. Refrigerant leak could do it as well, even Puron which contains no chlorine will make hydrofluoric acid when burnt. Is the blower direct drive? If not maybe the belt was slipping(noise)? Also check blower motor, winding insulation has a rather nasty odor when burnt, I have seen centrifugal start switches stick closed, keeping the start winding on all the time, makes for a nice smell and a short lived motor. Hope this helps and keep us posted. You got our curiosity going now:D

[docholiday]

I'm slightly more concerned about the furnace sitting on carpet. You mentioned the smell is coming from the supply side, you would smell anything coming from the return since it is under negative pressure, both sides need to be looked at. I'd say recommend the ducts get cleaned and inspected by a company that has some sort of camera, like you use to find obstructions in a sewer pipe. Also you mentioned a loud noise and then the smell, could be a critter climbed into the duct and hit the fan, has the blower even been pulled?

[zerman]

change your glad plug-in...(true)

[zerman]

sorry . glade plug-in

[options]

After several unsucessful attempts to locate the source of the odor indoors, the homeowners consulted a plumber, who armed with a camera proclaimed the source to be from a broken sewer pipe a few feet from a drain located near the furnace. When the homeowner removed the floor, he found that the plumber was wrong and that this pipe was not broken, but he did find a very serious problem with water run-off below that section of the home and hopefully correcting it will now solve their problem.

Thank you for your responses.

[docholiday]

Too bad that plumber didnt run his camera through the ducts, he may have found a cooked possum stuck in the first take-off.

[wormy]

Get a Carbon Monoxide alarm.

Even if its not the prob... anyone with gas appliances needs one.

Our gas dept will check for Carbon Monoxide for free....
I'd still want a Carbon Monoxide even if they didnt' find anything.

We have a better Carbon Monoxide meter than our local gas dept, I've found CO on jobs where they found nothing.
Its far better to have 24hr monotoring from a 30 dollar meter than a 5 minute walkthrough with a 1300 dollar meter.

_________________________________________

LET ME STATE THIS FOR THE RECORD.

CARBON MONOXIDE IS AN ODORLESS POISONOUS GAS

Just because your eyes burn or throat gets irritated does not mean Carbon Monoxide.

I include the CO check ANYTIME I have an unknown chemical getting in a house causing irritation.

[options]

I agree and also suggest that anyone with any type of combustion burning appliance or an integral or attached garage should have one.

[majormickey]

Is the home the same age as the furnace or is this unit a replacement? If the furnace was running during construction or renovations alot of things could have made it's way to the exchangers

[options]

Home is at least 50 years old.

[majormickey]

Might have some disassembling to do to get a look inside and out.I've had only one case where a toy went down the return air,it's possible "something" went through,but it's a stretch.The noise you mentioned coming from the unit wouldn't result from the "pipe problem" proclaimed by the plumber.The ball should be in the plumber's court especially if he charged for the mistaken problem or better yet,the installer because most guys would want to know about a problem with their unit for future reference as well.I'll be thinking of this one.

[icssales]

what is dirty sock syndrome?

[wormy]

Originally posted by icssales
what is dirty sock syndrome?

http://www.hannabery.com/dirtysock.shtml

[genesu]

Smell like something is dead inside my furnace, I cut open (disconnect) the duct that come out from the AC unit, didn't see anything, but when I turn on the AC, the smell come out from the unit. wondering if possible for some kind of small animal ( rat ) to get in there and die in there? What can I do to remove the dead animal? I am sure the smell isn't chemical, it smell like something decompose.

[Advanced Response]

Best I can tell you if you think it is truely a decomposing animal is to call a quality duct cleaning company that can clean your ducts and use a camera to look in all possible locations of the duct to find the decomposing animal and get it removed and duct area cleaned and sanitized..

Goodluck
J

[plexus]

Maybe one of the installers dropped something in the heat exchanger. Like some pvc or the furnace manual.

oh my god thats too funny