I posted this scenario in dirty sock syndrome, but fact is I don't have a clue. We are in a 16 month old house (second winter) and have been experiencing a musty smell from our return air after we take a shower. The system is a Lennox, but I do not think it has a heat pump. The smell is in no other room except the hallyway where the return air is located. I have had a plumber check the ventilation pipes for cracks, etc., leak pressure test on the water lines, duct camera inspection for mold in the ducts, and air condtioner guys out to check system out. All have no answers. When the duct service man came out, he said our attic did not smell normal so I am in the process of having the insualtion checked. Personally I have been in the attic and this does not smell like the musty smell in the return air. My duct person has suggested a duct pressure test, but I feel this does not solve my odor problem. He did say our house seems to acting under negative pressure because some of our doors will close when the unit is running and when it is off there is a small draft coming down from the return duct. HELP!!!
[Edited by charlezz on 01-26-2006 at 01:08 AM]
We were recently called out on a similar problem. every heating and duct cleaning contractor couldnt figure it out.I still cant either, but we torched the heat exchanger and coil with an acetylene torch,to burn off
Something like a deorderizer or bug killer was used and circulated is my theory prior to moving in. Lady says smell is gone and even sent fudge with a thank you letter.
never say never
do u have a crwal or basement ? possibly duct not sealed or that spaces smell reachin living space
Have your A/C's coil cleaned and see if the smell goes away.....it's downsteam of the furnace supply air.You wouldn't be smelling the return air.
If everything was always done "by the book"....the book would never change.
We have an attic, we do not have a basement.
I talked to you today charlezz,'
When you mention the draft coming down when the unit is off,this can indicate to leaking ductwork. Have someone inspect the ducts for leaks in the attic.A pressure check will indicate the amount of leakage, but not where. A/c coil could still have dirty sock,and most air drafting into bathroom during off cycles. I would say that its impossible to smell anything when fan is running.
The activated charcoal filter may solve the symptom,but not the problem.
Have them check the bath fan vent too.
We cannot by code,install returns in bathrooms or kitchens.
Thanx for the phone call,but it is better to send a message on this forum regarding this for me.
Good luck and let us know.
[Edited by contactor on 01-26-2006 at 10:24 PM]
never say never
rather than checking for duct leaks, have the ducts & ALL boxes sealed with mastic.
have the crack between the HVAC ducts & wallboard |floor sealed.
, then check for leaks, then insulated.
harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!
have a coil cleaned and duct work sanitized by a proffesional contractor
Draft while off
You have two issues
1. A draft that should not be.
2. A smell that should not be.
Have what ever dampers needed to be installed installed and get that system balanced or repaired. While doing this tell them to locate and inspect all duct work have everything sealed up nice. This will not only save you from the smell but save you money. You should not have air moving through the ducts while the unit is off unless you have some type of a problem. Can you describe the layout for supply and returns with unit location and duct material and location?
Do you think they may have cut the bathroom exhaust into the return duct? Why would you have a return in a bath room? I would think that would be a good clue.
Sadly, I have seen this before in new homes. I have also seen the dryer vents piped into the return. Time to pop off the exhaust fan and find out just where it goes. You may also want to consider a make up air/air to air exchanger to help with the negative.
Do you think they may have cut the bathroom exhaust into the return duct? Why would you have a return in a bath room? I would think that would be a good clue
Good? Bad? I'm the guy with the gun.
Statements made by me are strictly my opinions and do not reflect the opinions of my employer. I am not authorized to make any official statements on behalf of my employer.
Any technical advice offered by me is for educational purposes only, all HVAC related repairs should only be attempted by qualified personnel.
Hey Propmanage...thanks for the response. I did not mean a return in the bathroom; I meant we have a register and an exhaust fan in the shower area. When I get in the attic, the ventilation from the exhaust goes to the roof and out. As far as the layout. Our return duct is in the hallway and the duct goes through the attic and out the roof. We have a dual pack unit with everything located on the roof. In the attic, of course the reutrn air duct, along with the plenum and ducts branching off of that and going to the various rooms. The plenium box is also partly in the attic with the rest going to the roof where everything else is located. Hope that makes sense. Where could the smell be coming from? A serviceman came out and apparently cleaned the coil and sprayed Biofresh. Not sure if the Biofresh was sprayed on the coil or in the unit area. Could the smell still come back after that? Thanks
[Edited by charlezz on 01-30-2006 at 02:27 PM]
Look things over
Check the unit over you should not have air moving while off, also you may have a mouse or a damp rage or something in the unit. Coils can become homes for smell and germs if not property taken care of. Shut the power off and get close to the supply and return at the unit, see if you smell it at that starting point. Also almost sounds like you have an open outside air intake full open and possibly getting rain in it. Dont really know with out being there. Just keep looking until you find it, and you will if you take your time. That air moving is an issue to resolve.