Strange Odor from reverse 2 cycle system

[TJ-LJ Champion]

Since purchasing our Hunter 45cc a little over a year ago an odor has developed from the reverse 2 cycle heating/cooling system. Our boat is lived on 24/7 and the system is closely monitored/maintained.

I (the wife) cannot tolerate the odor which is somewhat chemical/ fuel based kind of like a strange natural gas. I cannot describe how it permeates everything and when bringing wash back to the house it's stench is still emanating.

I feel terrible, my husband wants me to spend as much time aboard, but due to the odor spewing through the vents, especially overhead in the master I cannot sleep comfortably.

Is this something I've just got to live with? We've washed and cleaned the vents, all the filters are cleaned regularly and the system has been charged recently for full efficiency.

Any help or suggestions would be greatly appreciated!

Laurie Champion

 

[Don S/V ILLusion]

From where does the intake air come? Assuming the units are oriented to allow the air intake to face outboard as they are designed, is it likely you are drawing air directly from the bilge area?

 

[Bob J.]

Check to see if the return side of the unit itself is ducted directly to the return grille(s).
Could be that the unit is installed in such a fashion that a return air plenum has been created pulling odors from other parts of the boat instead of just the cabin air.

 

[kloudie1]

Yes.. even small spaces like where the cooling water hoses and condensate drain come into the space should have some kind of seal to keep bilge air from being drawn into the cabin air intake.

 

[centerline]

im not sure how the system is set up on your boat, but I have had issues kinda like this in big trucks.... where the heating and cooling coils get a build up on them and then stink like hell when they cycle on and air moves past them.....
so in addition to checking the intake source like has already been mentioned, if you can get to the coils, spray them well with simple green and let them soak for a few minutes. then spray again and let them soak for 15-20 minutes and then rinse them well and see if that helps.... DO THIS WITH THE UNIT OFF. do you have a drip pan on the unit that may need to to be emptied and cleaned?..... if so, you may be getting odors from it.... good luck.

 

[Don S/V ILLusion]

Not to be picky but, unlike a home A/C system, there is no "return" duct on a marine A/C typically; it simply draws air in from the surrounding area behind the unit which is intended t suck across the compressor but is often open to the bilge or bilge pan.

 

[Bob J.]

Not to be picky but, unlike a home A/C system, there is no "return" duct on a marine A/C typically;

I thought about the reverse cycle on our old boat after I hit the send button....

The unit could be pulling air from other parts of the boat which would require sealing up the locker/cabinet wherever the unit is installed to prevent this from happening. Then again it could be just plain old dirty.

 

[TJ-LJ Champion]

Thank you for all those suggestions!

I do know the unit under the master berth is open sharing space with the fuel tank and bilge. When I get up there I will attempt to get at it and begin the bilge cleaning as well the fan blades and anything else that might be contributing.

There is an aluminum filter (I assume the intake) located just below the mattress platform. We've cleaned this numerous times but the fact this unit is not sealed and can pull from the bilge could be the issue.

I had thought of that but figured I'd ask here on the forum.

 

[DeniseO30]

Laurie, You don't say if the odor is in the heating cycle or cooling. I'm guessing when it's in reverse, heating.. Is the smell continuous or just when it's turned on? It may be mold/moisture/diesel fuel fumes (that you don't smell normally) heating up on the coil surfaces and even the electric heating element if it has one. Heated air that contains VOCs will smell terrible, and that can be caused by only a "trace" of Diesel fuel fumes.

 

[Don S/V ILLusion]

There is an aluminum filter (I assume the intake) located just below the mattress platform. We've cleaned this numerous times but the fact this unit is not sealed and can pull from the bilge could be the issue.

I had thought of that but figured I'd ask here on the forum.

Sounds like you knew it all along... That metallic filter will remove large boulders and mice and little else. Any residual smell from the bilge or any nearby open area between the pan and bilge will easily permeate the entire cabin once it gets sucked into the A/C fan.

For what it's worth, I helped a friend with a similar problem which was solved only by blocking off the void spaces between the A/C and the bilge spaces (in his case, along the hull topsides) and "making" the A/C pull from the fancy grate in the door to the locker where his unit was located.