Air Conditioning won't work after 5 day sail

[Suspicious Behavior]

I just bought this boat. It all worked great in two different Marinas in Kemah TX.

In fact the Air would literally freeze you out of the cabin.

So...sailed it to Orange Beach Al. Now it won't work.
It's on the 50 Amp splitter
It turned on for a bit...ran for three to five minutes....AC cycling on/ off.
So I cleaned the screen and the bowl that hold it
Turned it on again ...it filled the bowl about half way then shut off. Flipped its switch off too. Same result after trying to let it cool etc.
boat is plugged in, engine is off.

Is it some kind of vapor lock ? Air lock ?

Any help is appreciated.

Thanks
John. F

 

[Don S/V ILLusion]

. It's really difficult to provide useful advice in the absence of sufficient info. For example, is the pump on? Is it pumping water out the thruhull? Does the condenser cycle? Is there power to the compressor?

 

[Suspicious Behavior]

The AC selector is switched to on. There are two ACs on the boat.
What pump ?

It's not on long enough to pump water thru the out hull. But I did see it work in Texas.

Yes the condenser is cycling. Fan too.

My belief is there is power to everything.

 

[Davidasailor26]

There is a pump that pulls water in through a thru hull, cycles it through the AC to pull the heat away, then out likely through a hole above the waterline. That pump should be on whenever the compressor is running and you should see water getting pumped out by it. If not then either you accidentally didn't open the thru hull, or the pump is airlocked, which can happen after heeling depending on thru hull location. I'd trace the water line from the thru hull ooking for a bleed valve to let the air out of the system. Open that valve then run the AC until you have consistent water flow. Close the valve and hopefully you'll be all set.

 

[Gunni]

Common symptom of an air-locked A/C raw water pump. Check your raw water circuit and look for a discharge tap that will purge the air, or alternatively you will need to close the thru-hull and fill the raw water strainer before opening the thru-hull and restarting the A/C. Your AC control may be throwing a troubleshooting code that you can see.

 

[Suspicious Behavior]

Great stuff. Thanks. I thought about filling up the strainer and then putting it back.
Maybe even cracking it open half a turn to try and prime it.

Ever put and small Bromine tablets in that strainer cup when leaving it for a few weeks ?
That was also suggested.

 

[Suspicious Behavior]

Also, the book suggests checking the air filter. But the book doesn't show me where the dang thing is. Any ideas ?

 

[Gunni]

If all is working correctly you should see water discharging overboard the instant the AC compressor kicks on - that is what turns on the raw water pump. Don't put a halogen (bromine) in your strainer.

 

[BigEasy]

Its common for the AC to cycle on & off if there is an air lock in the cooling water circuit. Bet it isn't pumping water out of the water outlet above the water line when it is cycling. Happens to mine all the time if I forget to close the water inlet thru hull before sailing. The pump is supposed to be self priming; however, mine will not pick up sufficient water to prime the pump if there is too much air in the line. Try inserting the end of a water hose from the dock into the end of either the water outlet hose fitting or the water inlet fitting at the pump. (will have to remove some hose clamps to do this). Flush the system, reinstall the hose & clamps, fill the strainer with water, & power up again. You should see a steady stream of water from the water outlet & the AC unit should run normally. Might also check to see if the water inlet thru hull is blocked --you can use the water hose to flush that too if necessary. Its highly unlikely that a dirty air filter would cause the problem unless it is totally blocked. If you have two AC units on board, there may be one pump associated with each unit, if so, you will have to flush both water circuits.

 

[Don S/V ILLusion]

Also, the book suggests checking the air filter. But the book doesn't show me where the dang thing is. Any ideas ?

The "air filter" on most marine A/C units is a screen covering the condenser coil. If clogged restricting air flow, your A/C would freeze up but that takes a while so that isn't your problem.

Lack of water flow will damage the unit but also would NOT cause it to stop as quickly as you described. Sounds more like a defective pressure switch on the compressor. Could also be under -voltage or a number of other things I won't speculate about as speculation will likely mislead you.

 

[Pat]

Our Mermaid has a valve that I open after sailing to run water thru to reestablish a primed condition where the pump will suck water.....sometimes I have to do this and sometimes I don't. It seems to depend on how far the boat heeled over....I just open this valve, fill a jar with water and shut off the valve...then I restart the AC & it then works fine....

 

[Doug4bass]

Not sure how new your a/c is. Is there a error msg? Almost positive it is an air lock.

 

[uncledom]

SB I occasionally loose prime and do loosen the strainer cup to bleed air and get the water just close enough to the little giant circulator pump for it to reprime it's self. I have had a problem twice with growth in the little giant pump. After leaving the boat sit for a week the pump didn't seem to be working. You can hear it running but no water comes out. It turns out the impeller is magnetically connected to the motor! No actual physical connection. The least little thing can bind the impeller and stop it from pumping water but the motor seems to be running without problem or adverse load. That's because of the pump design. Of course my AC shuts off on HPF I think it says which I interpret as High Pressure Fault although that may not be what it means I know there is no water being pumped through the system. Once it stopped due to a sea grass clog at the pickup which I dove on to actually see for myself. One swipe of my hand and all good. When the AC/heat is working it's awesome and when it's not it's always annoying to fix. Good luck.

 

[kloudie1]

If "..flipped its switch...." means the circuit breaker tripped, then you most certainly have a condenser pump not pumping.. The condenser is not condensing which raises the compressor discharge pressure which loads the compressor more than normal which will trip the HPF alert or the electric breaker. it only takes a minute or so with no water on the condenser to trip... Big Easy has it..
The filter is over the evaporator coil usually .." Prime the pump" as the song goes.." you must have faith and believe..." (Desert Pete, by the Kingston Trio)

 

[Benny17441]

Sounds to me like you have a cooling water flow failure. It can be a bad pump, a blockage on the intake through hull (plastic ice bag), a blockage on the strainer (sea grass) or the need to prime the system. Check the intake port and fill the strainer bowl and lines with a hose then try again. The A/C has a safety shutoff to prevent compressor damage when the cooling water flow is interrupted.

 

[WayneH]

Sometimes, your blockage is outside of the boat.

Yes, he's stuck in the A/C inlet. I told the owner she could restart her A/C and cancel the service call.

 

[woodster]

 

[JamesG161]

You have a lot of great advice on how to clean/clear the cooling water pump system. In the Gulf Coast marinas we get algae more than sea weed. Algae will coat the AC heat exchanger and restrict flow.

Self Priming Centrifugal Pumps Tips: (typical AC cooling water pump type)
1) A completely dry pump will NOT self prime. You must get some water to the priming head.
2) To prime, the air must be ejected along with some water. No flow, no prime.
3) Continuous Surging or spurting flow on discharge indicates an suction line air leak.
4) The final exit on your boat (normally above the healed water line) must show some flow or it is not pumping.

As BigEasy noted in post#9, we have to flush/blow out the slime/algae/crap (mine 3 times a year). I use something like this on the end of shore water hose and jammed in the pump discharge hose.
https://www.amazon.com/dp/B0015AOQU...=UTF8&colid=F4YB2UW81A1O&coliid=ISC2V28H6LEO7
or this cool little connection adapter device...
https://www.walmart.com/ip/29764290 (you need to watch a video on it! Great Santa stocking stuffers!)

Don't put a halogen (bromine) in your strainer.

On my system, I have verified that I can put bromine tablets in my strainer. This is NOT a general suggestion, but it kills the algae/slime that coats the AC heat exchanger. I do this on a limited, shock effect, type basis. Spa/pool heaters use a cuprous/nickel heat exchanger tubes, that resists bromine/chorine pool chemicals. I verified that my AC has that heat exchanger material. So use it wisely.

Jim...

 

[Cwoody]

John,
The Non self priming pumps on these AC units are a pain. On the Flagship AC I installed on my B331 and now on the new Cruise Air. When the water stops pumping overboard, I usually have air lock. Happens after some lively sailing and Also happens when I take the raw water filter off to clean. Unit cycles for a minute then shuts down. My new Cruise Air has a bleeder valve installed just past the pump (thank you Cruise Air!). I turn the AC on, open the bleeder and the air is forced pass the pump out the bleeder. Once you get a solid water stream from bleeder, you should be good to go. Might take a couple of cycles depending on how much air is caught on the filter side. Got a stadium cup positioned to catch the H2O so bilge stays dry. Good Luck.

 

[Suspicious Behavior]

OK ..... I read all the replies, listened to the song. And have all the necessary tools to do the job.
Can't wait to get back to the boat to try this out. I've got to "Prime The Pump ". Hopefully that will do it.

Thank you all for contributing. As this is my first Boat, I'm sure I'll be back for more wisdom

Thanks again.