AC Units for Beginners

[Jonah]

Hi all,

On my '95 272, there is an aftermarket "Mermaid" AC unit installed behind/beside the refrigerator. I don't have the manual with me at the moment, but can send specs if that would be helpful.

When I bought the boat, the dealers tested the unit and found it to be working. Installed a new control panel for me even so.

Things seem to work overall: the fans cut on and off like they should whenever the temperature drops above whatever I've set it for, etc. And from inside the cabin I can hear the water pump working, and see water pumping out of the thru-hull on the port side.

The thing is: the air coming out of the vents just isn't cooled. If this were a household AC unit, I'd say that the thermostat is working fine, but that the unit needed some more freon or something.

So, what's the most natural thing to check first for an AC unit that does everything right except cool the air it delivers? I'm a complete beginner in this area.

 

[Fishtales]

You prob need to get an AC guy to look at it. Sounds like you lost the refrigerant. For a unit that old, they may have to recharge and see what happens. If it leaks again, they can install a dye to attempt to locate the leak. Could just as easily be a mechanical thing. Might be worth replacing the entire unit as once you get a guy in there the meter is running and you can spend quite a bit and end up with a fixed old machine that is likely to breakdown again.

 

[g0tagrip]

On my Sailfish the a/c uno was under the forward compartment of the V berth. Not sure where your's is but there is a reset button on the unit, I have had to reset the compressor not only on my Sailfish but also on the Marlin. Where is your a/c unit located? If under the V berth like my old Sailfish it is easy access to reset the compressor. If it is behind the steps than there is an access panel to get to it. You will need a flashlite to see the reset switch. I would try that before calling a tech out.
Let us know if that fixes your cooling problem.

 

[Jonah]

Thanks Fishtales, Thanks Gotagrip,

I will have a look for the reset button. Mine is under the stairs, but I have good access from a panel on top of the 'counter', behind the fridge.

 

[Jonah]

g0tagrip, you are my hero. Found the reset switch, and that was all it needed. Easy to spot; easy to reach—simplest fix ever. Thanks for letting me know.

 

[Jonah]

I am at a marina right now, and my AC is acting up. System works fine overall, and air is cooling well. But fan cuts off every 10 mins or so, and won’t come on until I turn the unit off for another 10 mins or so. When the fan cuts off, the system is still running, humming, water coming out of side of boat, etc. Just no airflow at all. Even if I turn the fan setting to ‘on’ instead of auto. It’s like it just needs a break.

Any ideas?

 

[Jonah]

Problem got worse, so switched from ‘cool’ to ‘off’. Left fan in ‘on’, not ‘auto’, but no fan action. 30 mins later the fan kicks on. Very strange.

 

[Jonah]

Update: Spoke with Mermaid tech support, who believe it is a thermostat issue. They gave me a test to run, basically hot-wiring the AC system to bypass the thermostat and see if it runs properly then. Will know soon.