Cruisair Burning Smell When Heating

[EmeraldCoastSailor]

I have a single 12,000 btu unit with ducting to rear cabin, v-berth, and of course the salon. Air flow is good and the unit heated well for about 12 hours solid last week until I started smelling something burning. It wasn't bad but I turned off the unit and went for breakfast. I started it again a few days later and smelled it again. There is definitely something coming out but not thick enough to see in terms of smoke. I am sure if I ran it for 30 minutes the boat would not be habitable. Prior to last week the unit hasn't run long in heat mode for several years. Last I ran in AC mode months ago it worked fine.

It blows warm air. Fan doesn't sound any different. Nothing is hot. Nothing apparently wrong when inspecting the unit under settee. Nastiness is coming from vents.

Any ideas? How do these things fail? Something isn't right.

[Scott Berg]

Are you using the reverse cycle or are you using a heat tape system at the fan blower?

[Cavalier]

Have you thoroughly cleaned the catch pan out below the coils yet? Typically, gunk builds up during the summer when it's in AC mode. It wouldn't take much for said gunk to get heated up over a long period and start smelling foul..

[EmeraldCoastSailor]

Originally Posted by Scott Berg

Are you using the reverse cycle or are you using a heat tape system at the fan blower?

Yeah, I am pretty sure it is a reverse cycle unit. I am not aware of a "heat tape system at the fan blower"

[Outlaw7]

Heat Pumps(Reverse Cycle) turn the evaporator into a condenser and the condenser into an evaporator when in the heat mode. So where the air blows through gets warm. If you have not had it cleaned in a while, if ever the dirt, hair, and other detritus will start to cook, hence the smell. It should burn off and yes most units sit in a pan that collects mold and mildew that may smell as well. A Flagship Marine unit has a sloping drain pan that actually drains. No mold there! They also use heat strips that work without running a water pump!