2005 Cruiseair AC - musty smell, no cold air

[Tspringer]

The original rear Cruiseair AC in our 2006 Beneteau 473 is having an issue I need to fix. The AC unit blows cold when first turned on but after a few minutes it stops and instead blows warm air with a sort of musty smell.

Any ideas on cause and remedy?

I am trying to remove the entire unit from the port aft lazarette in order to give it a thorough cleaning and ensure the evaporator (radiator like part the intake air blows over to cool and then get distributed) is not blocked with dust or debris. I think this is likely as viewing/cleaning it is impossible without removal of the entire unit which I doubt has been done in a very long time. I also want to run a small snake through to clear the cooling lines as the amount of cooling water coming out does not appear to be enough. I plan to replace some of the lines as well.

Getting the unit out so far is a bear. I removed the 2 screw down fixtures holding it to the wooden mounting plate but it still does not budge at all. I am wondering if it was installed before the deck was installed in a manner making removal without demolition impossible. Wouldn't surprise me.

Any ideas are greatly appreciated! The budget says a new mainsail before a new secondary AC unit so I really needs to get this one to give a couple more years!

Terry

[Greg Brannon]

How the system has been serviced and taken care of throughout its lifetime can be an indicator of what is going wrong now. It sounds like raw water cooling is insufficient, or the refrigerant could be low. That you have cool air initially leans towards raw water, but both could contribute. To DIY service, check the coolant pump input and output and ensure that the pump running when it's supposed to - at a minimum when the unit's compressor is running. If you believe the coolant water output is low, I recommend flushing the whole raw water coolant loop with a flush chemical rather than trying to snake it. Create a circular flushing flow with either the existing pump or a flushing pump and let it run for the time recommended by the flush product. Note that the existing pump is probably not self priming, so ensure that the flush chemical source is higher than the pump. I use a sump pump in a 5-gallon bucket filled with 3-4 gallons of appropriately-diluted flush product.

My 5 split systems were much older than yours and spent! Removing/replacing them was a bear. I had to replace the sole to which they were attached. I can't know how yours might be fixed in place, but there were more than 2 screws holding each of my units in place.

Best of luck!

Greg.

[bstreep]

Almost 20 years. I think it might be time to look for a replacement... But the advice above is good advice: Clean your heat exchanger lines, clean your coils. They make a spray coil cleaner and coil brush.



That being said, if you can't feel the lines running through the coils getting cold, and your sea water coming out of the heat exchanger isn't getting hot, then you have bigger problems. Might only need a charge of freon, though. Probably R22

[Turtle Blues]

Follow comment 2 first.
next - important distinction does it blow warm as in heated air or just warm air from where unit is located?
In either case the musty smell is the buildup on the evaporator coil and whatever may be in close proximity to it, hence need to clean.
Next air temp question, if it is simply ambient warm air that is the fan running with the compressor off. If it is indeed heated air and the system is a heat pump, that is the electro-magnet on the reversing valve failing. Still not catastrophic as the internal part of the valve is still moving. The magnet is externally mounted on the valve with a single nut and can be easily replaced. As long as the compressor works and the system holds pressure it is serviceable.