Newb A/C issue

General lack of info on this but will ask anyway... new to me older Grand Banks 42 with 3 A/C units - forward, salon and aft stateroom. Flipped a main power switch while two of the units were running which I shouldn't have done but....newbs are dumb. Switch cut shore power to the boat. Oops. Turned it back on and the salon A/C powered back up but the one in the stateroom...not so much. Turned unit off then on then off then on..nothing. Question is whether or not, generally speaking, A/C units have a dedicated fuse between their power source and the unit? A reset button on the unit maybe? There is no circuit breaker for the units on the panel. Just want to check fuse first..if there is one. Not sure which manufacturer. Haven't gotten there yet.

Sorry for stupid. You can't fix it.

Most modern AC units have built in time delays. If you try to turn unit on right after it has shut off for some reason it will probably do nothing. Wait a few minutes then give it a try. If still nothing, look for time delay self resetting fuse/breaker on unit. Hard to believe there is no breaker feeding the unit. First thing after you eliminate this problem connect it to a breaker. Goo luck.

Are you sure theres no breakers for them?

Could be the delay could the compressor locked up if it short cycled.

Could be a number of things, need more info.

If it's a standard GB installation you should have a master breaker and individual breakers for each A/C. As well as a breaker for the A/C raw water pump in many cases.

also most makers will have a fuse into the main unit - look to the control box that will be either mounted on the unit or close by.
Agree - need more info.
DT

Hate to question you on this...are you sure those units don't have individual breakers? I used to have a boat with 3 AC units and each had a breaker. I can't believe Grand Banks would have those units wired directly to the main circuit with no breaker.

Thanks for the replies and comments. Have been traveling with little online time so just now catching up. Will be back to the boat tomorrow and will do some chasing down. I know that each of the three units HAS to have a breaker but they and are not on the main panel. Since it is a new to me boat my attention has been on getting familiar with other systems. Seems that my wife thinks that my attention should now go to the AC unit. I emailed the PO about the location of the breakers but haven't heard anything. Shouldn't be too hard to run down. I believe they are Marineair units but can't even confirm that right now. Someone mentioned the chance that the compressor locked up. How do I check for that if the breaker/fuse checks out ok? Not sure on whether or not they I have an internal timer as well. Do know that we had two units running when the switch was flipped when it was flipped back on the main salon powered up but the after stateroom did not.

I'm not an expert, but the first place I would look is on the actual a/c unit for a fuse/reset button. I had that issue on an older boat a few times and that solved it. Good luck.

it wont be a locked compressor unless its a catastrophic failure for the compressor. A locked compressor will usually come good after the gas has equalized - hence the delay in restarting sometimes.
if the controller wont light up or the fan wont start you have to look to the input power.

Found the circuit breakers in the engine room. One breaker had flipped. Now working. Only real issue is the newbie owner. Duh. Did try to find any reset buttons on the individual units but they are closed in by a finished install box. Maybe accessible from the front...if they exist. Have to pull a manual online and see. Need to find out how the refrigerant is refilled as the V-berth unit lags the other two in cooling....

firstbase said:

Found the circuit breakers in the engine room. One breaker had flipped. Now working. Only real issue is the newbie owner. Duh. Did try to find any reset buttons on the individual units but they are closed in by a finished install box. Maybe accessible from the front...if they exist. Have to pull a manual online and see. Need to find out how the refrigerant is refilled as the V-berth unit lags the other two in cooling....

Click to expand...

Get Nigal Calder's book.

Already have it. You should have said "You have the book dummy, now read it." Lots to learn with this bigger more complicated boat. So far I am going where the wind blows. Learned A LOT about heads, holding tanks, a clogged vent line and how to clean up a bilge full of OPS a couple of weekends ago. (Thank you very much Peggy Hall if you happen to be reading this one). Anyway, the PO did some customizing of the electrical system and batteries that I do not get so am having an electrical guy coming to the boat this week to help me sort everything out. Have taken the boat out a few times without incident and it is great. However...only a matter of time before something goes BOING and I need to up my basic understanding of things because I don't know crap. Well, actually, after the holding tank vent fiasco I DO know crap....just not the crap I need to know. Anyway, thanks to all for the replies.

When you turn off a running compressor it still has a high head pressure. Then if you quickly turn it on, the motor locks cause it can't spin against the high head pressure, the locked rotor draws high amps and the breaker flips off.