A/C Help Needed

B

bobn

Member
exMember
Joined
Jul 1, 2008
RO Number
30338
Messages
70
I'm a novice when it comes to marine air systems. Here's my problem...the raw water cooling pump won't come on when the salon A/C cycles on. I have two different units, one in the salon and the other in the aft stateroom. Both units are wired to the raw water pump by some type of board. This board has 110 power connection along with connections for the water pump and both A/C's. I wired the water pump directly to the 110 power and the pump runs. With the water pump wired to it's terminals when the main A/C unit cycles on the pump will not work. If I switch on the aft stateroom A/C the pump comes on. I assume the aft A/c is a slave to the salon unit since it will not operate unless the main A/c unit is on.
I would assume the circuit board is bad, but the aft A/C turns the water pump on. Could the board be bad and still operate the water pump with one unit and not the other?
Any ideas what to check would be appreciated.
 
Burnt out triax at the saloon unit is my first guess. That is the "switch" that turns the pump on when the compressor comes on.
 
there are no slave on an AC system, either unit should turn on the pump. If one doens't then its trigger is bad. pretty simple and pretty common failure. you shoudl be able to replace it yourself depending on the model, the ones i have on my boat disconnect fromt eh main board.
 
Where is the triax, what does it look like, and how do I check it.
I'm really a novice with the marine air, but I rather learn what makes it tick instead of calling a pro if I don't have to.
 
Need to know what brand and type unit you have. I had a bad relay in my unit and the pump ran all the time.The relays control the pump and turn iton when either unit is turned on.The relay on the left was bad. The water pump starts on my A/C when the fan starts on either unit.
143.jpg

134.jpg
 
When mine went out I made one from a couple of refrigeration compresser start relays I had laying around.
Note: These are not spark protected and should not be used if you have gas engines and are mounting it in the engine room.

HPIM0733.jpg

Note to all electrical gurus out there, I had one more white jumper wire to install when the picture was taken. And also the green grounds.
 
Marine Air; two A/Cs, one pump. Pump only comes on when compressor kicks in. Obviously, either A/C will start pump when compressor comes on.
 
swap the power control boards and see if the problem moves.
 
Rather than swap boards it is easier to run a power cable from the pump to the pump start terminals on the AC unit, bypassing the pump controller. If the pump starts when that unit is turned on then the board is OK. Do each one induvidually to check the boards and eliminate them. If the pump fails to start on one AC then you have a bad board. If they both work then you probably have a bad relay in the pump controller.
Make sure you have the other AC breaker turned off for each test as often they are on opposite legs on your panel and you may have a 230 volt hazard.
 
I would say you have a problem with the a/c thermostat control, the pump control
panel or the wiring between the two of them. It could be just a little corrosion
on the terminals or something like that.

I worked on a new Bertram that had 2 a/c's and one freezer all on the same pump.
The owner was having trouble with the forward a/c going down on high pressure.
We could not figure out what was wrong, everything looked great almost all day.
We finally tried to check only the a/c with the problem and shut down the freezer
and the rear a/c. The forward a/c went down right away.
Turns out, Bertram installed the wrong pump control panel. It was for the rear
a/c only. When it ran, the other one and freezer ran fine. In the evening, when
the rear a/c would finally cool down the salon, the other one was shutting down
on high pressure. So was the freezer, but it wasn't noticable like the a/c.
We called Bertram and they sent the new pump control panel. Everything works fine
now.
 
You must log in or register to reply here.
Back
Top