AC Units on New-to-me Boat don't work

[Montenido]

Hi folks,

I am on a new boat (to me) and still learning the systems. This boat has 3 AC units, and none of them seem to work. The indicator lights on the breakers all go on when switched on, and the control panels all have power and info showing. I have accessed all the cooling pumps and they do not have a separate breaker, so I am thinking that they are turned on when the power feeds the units.

I forgot to look at brand and models, but will when I visit the boat next. Are there some simple DIY tests that I can do before calling an electrician/AC guy?

Any info is greatly appreciated.

Cheers, Bill

 

[Bigsfish]

Check to make sure when the cb is turned on you can hear the salt water pump start. If not check to be sure there isn't a separate cb for the pump.

Check to see if you can hear the AC handing unit kick in.

That's to start.

 

[Montenido]

Bigsfish,
with the CB turned on for the AC unit, the cooling pump does NOT turn on. I have searched everywhere for a breaker for the pump(s), but can't find one.

Thanks, Bill

 

[Delfin]

Bigsfish,
with the CB turned on for the AC unit, the cooling pump does NOT turn on. I have searched everywhere for a breaker for the pump(s), but can't find one.

Thanks, Bill

Check for a red reset button on each unit. There won't be any power to the pumps unless the unit is cooling, and the unit won't cool if they need to be reset.

 

[BruceK]

Did you have a surveyor, he will have tested all systems and know how they turn on and operate. Perhaps.

 

[Bigsfish]

As a last check, trace the wire from the pump back to the source as see if you have power.

 

[Montenido]

Delfin, great suggestion, thanks. I'll check next time aboard. Alas, the surveyor was very thorough, but still missed a few things.

Cheers, Bill

 

[Bigsfish]

Your surveyor had to have run the AC unit (s).

 

[CaptTom]

Just for the record, not all salt water pumps will come on with the circuit breaker powered.

The way mine (and many others I've seen) are configured is that the pump is powered from the air conditioner controller and only comes on after the thermostat has closed, signaling the controller to start the run sequence. Then, first the sea water pump, then the fan, then the compressor are started. Or maybe those last two are reversed, I forget.

At any rate, an electronic thermostat is also powered from the controller, so if that has lights then the controller has power.

A more common failure mode would be the seawater pump and fan start, but there's some problem with the compressor. At that point I'd go right to the reset button on the compressor.

Another thing I've seen is everything else works, but the fan is stuck. If you can get at it, try to spin the squirrel cage. If there's resistance, or it doesn't coast down but just stops when you stop spinning, it might just need some help to get going, after not being used for a long time.

I'd be interested in hearing more about how the OP's three systems are configured (one pump or three? Electronic thermostat? Split system?) and which components do, and do not, come on.

 

[Bigsfish]

Captain Tom

I agree. Perhaps I wasn't clear but the thermostat (the brain) has to be powered and that in turn tells the water pump to start. If not anytime the CB was on the pump would run and that would not be a good design.

 

[rwidman]

........... the surveyor was very thorough, but still missed a few things.

The air conditioning system seems like more than a "few things". Call him and ask him about it.

 

[Donna]

I find it strange all 3 do not come on. Seems there may be a common link. I just got finished installing a super quiet 16,000 btu Marinaire that is incredible. However, went to the boat 2 days ago and it was not getting power. It was only a loose connection. What do all three of your air conditioners have in common? The pump?

 

[Bigsfish]

Donna

Perhaps but not always. I have four units (compressors) and have two intake pumps.

 

[Maerin]

Look for a pump relay control. If you have 3 A/C units and a single pump, there must be a relay that powers the pump but won't backfeed current from the pump to the other A/C units that it serves. Very common application. Typically, the pump circuit will have its own CB. There would be a 110V supply from each of the 3 A/C units that should be connected to the "pump" terminals on the A/C end, the other end would be connected to the relay box and would power the relay coil that closes contacts to start the pump. Each A/C unit would power a separate relay, so yours should have 3 relays wired in parallel- one for each A/C. Some of the older CruiseAir systems use a relay configuration that uses a replaceable relay module they call a "driver" in the relay box. Failure of the driver component will cause the system to not work.
If you have access to the power panel on or near the A/C unit- it will be in proximity to the compressor- see if there's a "pump" terminal, and follow that cable to it's destination. Or- follow the power lead on the seawater pump back to its source. Look for a panel with 5 cables connected - one for each of the A/C's, one to power the pump, one for supply power. Might be helpful if we knew the make of the A/C units. Ask a technical question with technical information.

 

[Ski in NC]

Could be a problem with shore power connection. Will AC's work on gennie?

 

[Montenido]

Hi folks,

Thanks for the great suggestions so far. I'm sorry but I did not record the make and models of the units, but will next time I'm a the boat. The 3 systems each have their own cooling pump. I was going to try them with the genny running to see if that makes a difference. The survey shows that all 3 units started and performed when tested. At the time, the boat was hooked to 50a 240v service. At the moment it is only on 30a 110v service. Could that make a difference?

Anyway, I will get back down there and try the things that have been suggested. I will get make and model info also.

Thanks you so much, Bill

 

[Insequent]

I think you just nailed it yourself. Hook up to a 50 A service, or run the genny, and try again.

 

[stubones99]

Look at a soft start controller for the AC compressor, since they drop the current required to start them.

 

[Maerin]

Hi folks,

At the time, the boat was hooked to 50a 240v service. At the moment it is only on 30a 110v service. Could that make a difference?

Thanks you so much, Bill

That could make the units not function if they're wired for 240V! Small but crucial detail! You'll need to be wary of connecting only a 30A shore power until you determine how things are wired. You could create an unexpected cross connection, some backfeed, all sorts of weird stuff. If you only have 30A connections, get a smart-wye to get the 240V supply to the boat and I'm sure things will be cool..... (cool.. so clever...)

 

[what_barnacles]

Like was said earlier try the generator it's most likely wired to Output 240 volts.

 

[Montenido]

They Work!

Hi everybody,

I finally did the generator test with the AC units and they all worked! . Yes, I'm a dummy, but I am still learning the new boat. Thanks for all the great suggestions. I wish I could say that this will be my last post of this type, but I doubt it.

Cheers, Bill

 

[Bigsfish]

Congrats, I love a happy ending (no comments guys). Better when you don't spend $$$.