Air Conditioner odor

[Good News]

For the last couple of seasons we can smell like a holding tank odor sometimes in our cabin. I have checked everything I can think of and there is no smell in the bilge or when you flush. This week we realized we only have the odor when the cabin A/C is on. Has anyone else experienced a problem like this or have any ideas on what could be causing it?

[bud37]

If you want to eliminate the holding tank etc from the search, take a cloth , soak it in hot water then wrap it around your waste lines .......let it cool while still around the line ( hose) , then take it outside and smell...if it smells then your waste line is permeated and needs replacement....starting with the discharge /pumpout line then do the waste tank inlet hose.Try this and see what happens....AC could just be picking up door off ceiling and blowing around for you to smell.

[g36]

I don't know what boat you have but I can tell you I had the exact same problem with my carver 405. The AC unit under the front berth was drawing air from the bilge which does smell from the holding tank etc so when it was on it pulled the stink in to the cabin. I eliminated this by taking out the unit building a box inside the space to isolate the hvac from the bilge reinstalled the ac unit used flex duct for air return from the grille and reused the original supply ducts. It operates more efficently than it was cause I'm not heating or cooling the bilge space anymore and the smell is also gone. If you have any open area to the bilge like this your ac will do this also. Can't understand whose bright idea at carver this was but it's fixed on my boat now. I would check around this may be your problem also.

[Wayne162]

I agree with the previous comments. Look for the source of the odor! If it smells like septic and your bilges are dry then you have found your root problem. I previously posted a topic when I replaced about 15 feet of old septic line from my rear head. It eliminated allot of the odor I had in my 405, but never totally removed it. Now in the summer, when the A/C is on it blows out the vents even after treating the tanks that were in dire need due to a lack of maintenance from previous owners. A check of the off shore pumpout lines and the port pumpout supply lines noted the lines were most likely original equipment from 1997. In the fall I plan to replace them to with new lines. You should check the septic lines to cure the issue or your just masking the problem.

[Good News]

I really appreciate your answers and opinions on my odor problem. Even though there is no odor in bilge I think I will attempt to change all sanitation hoses this winter even vent hose. As the boat goes in heated storage it allows me to do some stuff during winter months. Thanks again and I will let you know next season how things go.

[mjk1040]

Just a thought, make sure your AC evaporator pan is draining. Any standing water over time will give you the very same smell. Do your shower sumps get used a lot? If not they too will start to smell with the standing water in them. Just read a note on our 1998 Carver 355 AC/MY that suggested running the water for a few minutes after using the shower to get the soap, etc. out of the sumps that will cause an order too. Mike

[Lyndon670]

Good News, just a thought for you. I changed all my aft stateroom hoses this spring and would suggest that unless the temperature in your heated storage is room temperature, don't even consider doing it in the winter. The sanitation hose is very hard to work with and pull thru confined spaces unless it is st least "warm".

[tonyiiiafl]

Source of the post I don't know what boat you have but I can tell you I had the exact same problem with my carver 405. The AC unit under the front berth was drawing air from the bilge which does smell from the holding tank etc so when it was on it pulled the stink in to the cabin. I eliminated this by taking out the unit building a box inside the space to isolate the hvac from the bilge reinstalled the ac unit used flex duct for air return from the grille and reused the original supply ducts. It operates more efficently than it was cause I'm not heating or cooling the bilge space anymore and the smell is also gone. If you have any open area to the bilge like this your ac will do this also. Can't understand whose bright idea at carver this was but it's fixed on my boat now. I would check around this may be your problem also.

I am having the same issue in my 1994 CPMY and saw how the A/C in the aft cabin is drawing bilge air. Do you have a photo of the work you did? I was thinking the same thing of isolating the A/C via a barrier to the bilge and duct the return air from the area where the filter is, under the berth. A couple of photos would be SO helpful!

[g36]

hi i had my issue with the under the berth forward ac unit of my 405. i actually added my aft cabin ac myself as my 405 didnt have one from the factory as a option. i thought this was strange because it sure is needed. they were trying to heat and cool the aft cabin with the salon unit. also i didnt install it where i think it originally went which was under the bed. i could not see how to get the duct work to high areas in the aft cabin very easily. i chose a storage area in the room and it worked out just fine and i didnt have to worry about the bilge issue . not sure on the 444 if the oem location is under the bed but guessing it might be.. what i did on my forward ac was to remove it and basically build a enclosure for the ac unit to sit in and run a large flex ductfrom the enclosure directly to the return grille and then flex lines out to the ac supply ducts thus eliminating the ac from pulling bilge air and forcing it to draw only room air in. this wasnt really easy but instantly stopped the issue with the smell.if you can find a way to seal off the unit wherever it is it will be way more efficient since you are not heating or cooling the bilge too. i have replaced my sanitation lines which needed to be done too but i still have a 19 yr old funk( probably the holding tanks ) that still lives in the bilge no matter how dry and clean i keep it. i was surprised to find the ac installed like it was just thrown in, to me it would be like having your house ac draw air from the crawl space.

[tonyiiiafl]

Exactly! The AC in the aft cabin is under the bed. The area is totally opened to the bilge. I was thinking of just sealing the area off and ducting the "fresh" return air from the cabin in via duct. I am going to scope it out this weekend and make things happen. The smell of bilge while sleeping is the most horrible!