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jlogan · 03-02-2008, 09:55

Seems like I am jinxed with 16000 BTU Marine Air Units...I have an approximately 2000 model, so 7-8 years old in a 37 foot gulfstar. Unit installed under vberth, worked fine until the other day...I had left it in heat mode for a couple of days, came back to the boat to find it off, the main internal panel breaker for the boat thrown as well as the a/c breaker. Tried reset, both breakers trip again. In troubleshooting, I find that I can get the fan to work (Passport II digital control model), but if I try to get it to heat or cool, it trips both breakers. I think it is when the compressor tries to start, as I hear the reversing valve reset, nothing happens, then bam, both breakers trip. Nothing else trips the breakers, so I am reasonably sure the breakers are ok. I'm thinking locked rotor on compressor, or ??? My question is, is it worth replacing compressor, or does anyone think I have a control box problem. I had an older marine Air unit in another boat that I actually fixed the circuit board on (helps to have a EE for a friend), but this seems like a different problem, since the breakers are tripping..can the circuit board cause this sort of problem? I am having difficulty seeing how a circuit board could cause breakers to trip..

any help appreciated...I especially need troubleshooting tips..

Anyone got any ideas?

AnchorageGuy · 03-02-2008, 10:52

It is hard to say without doing some on site troubleshooting so a AC tech is going to be needed. But my best guess is that the compressor is toast and will need to be replaced. I urge you to not keep trying to reset the breaker till you determine the problem. Unless you have the equipment to diagnose the issue it will be hard to determine.

jlogan · 13-05-2008, 18:05

This ac problem was caused by a faulty Cal circulating pump for the sea water cooling. Changed out the pump and no problem. The way to determine it is to unhook the pump from electrical panel on the ac unit, start the unit. If no circuit breaker popping, then, the pump was the problem. Be careful if you have this problem, as some of the Cal pumps fail in a way that electrifies the outside case of the pump.

I replaced it with a new Cal pump, $147 at West Marine, for a change the WM price was actually lower than Defender...no problems since replacement.

Therapy · 13-05-2008, 18:12

Good for you.
Another bit to file away.

svHyLyte · 13-05-2008, 19:45

If you have the oil cooled 500 GPH Cal Pump do yourself a favor by contacting Depco Pump in Clearwater Florida and ordering a March MDX-3 5/8. You'll need it. The Cal Pump was designed for underwater applications. The motor body is stainless steel while the pump housing is bronze. They are bonded with epoxy. The problem is that because the Cal Pump is not submerged as it was intended to be, it gets VERY hot (and is noisy!) The differential expansion rate between the stainless motor housing and the bronze pump housing will eventually cause the epoxy to crack, leak the oil out and that's the end of the pump. You can extend the pump life somewhat by ensuring that the stainless steel band that supports the motor housing is flushed up over the epoxy joint but it will eventually fail anyway. Friends of ours with the same AC Unit have now been through 5 (F-I-V-E) pumps in 3 years.

The March MDX-3 is an open body, air cooled, unit with a magnetic pump drive. It has oil channels that allow one to inject 20 weight lube oil (3-in-1 Oil) into the bearings. Our last Pump lasted 18 years and would still be working were in not for someone having repainted the motor housing and blocking the oiler galleries with paint at some time in the past. The Pump motor mount can easily be adjusted to ensure that the lubrication galleries are on the top of the motor. Best of all, the pump only costs $135.00.
Been there, Done that, Got the T-Shirt.

Best of luck!

s/v HyLyte

jlogan · 14-05-2008, 06:12

You may be right about the Cal, that is what appeared to have failed, as some of the oil had leaked out of the old one that I had not noticed because of the location of the pump. However, I had a March on my previous boat's ac system, and while it worked for years, it was much noiser than this new Cal pump. They were in similar locations, in a side locker. This new Cal pump is very quiet...we'll see if it stays that way.

I am aware that the March pump is a better design than the Cal, but when I was shopping, I found the March pumps much more expensive for an equivalent pumping capacity...

The March design should last longer, I'll agree..like most of life, pay me now or pay me later...but with a boat, you will pay...

gonesail · 14-05-2008, 08:07

the march pump is the best for the money. it is water cooled and will run in any liquid. the mermaid units have a reset switch that will activate when the cooling pump fails and the unit overheats .. this will save your compressor.

The Mons · 20-05-2008, 16:39

I thought this might be of humor to anyone with a Cal pump on their boat.

When my hightech Shuflo pump corroded, I initially replaced it with a Cal. I noticed that the Cal became extremely hot.

When I contacted Cal's customer support, I was connected to a very nice woman. She instructed me to keep the pump submerged in a BUCKET on my boat. When I asked her if she was serious, she admitted to me that she did not know anything about boats.

Needless to say, I returned the Cal to WM. I now happily use a March.

I also under stand that at one point a company was making a device for using the Cals in water on a boat. It was called an Ice Cube. The device was a clear plexiglass enclosure within which would sit the Cal. The movement of the pumped water through the cube allowed the Cal to receive the proper cooling that it was designed for.

I cannot image anything more likely to sink your boat than having 500 gals per hour being pumped around inside your boat through a thin plexiglass box.

**GordMay** · 21-05-2008, 03:38

Depco has an excellent pump tutorial, beginning at:
http://www.depcopump.com/catalog108/Contents.pdf

And their extensive line of manufacturers is listed and linked at:
Depco Pump - Brands, Vendor Links & Data Sheets

Jerry Mcgraw · 24-07-2014, 12:32

the same thing happened to me only while the air was running I turned the switch to heat momentarily then the breaker tripped. Now every time the compressor kicks on the breaker trips (heat or air) , I bypassed the control panel and direct wired the seawater pump and that did not trip the breaker, then direct wired the AC to 120 and it ran until the compressor started up then ran for 5 seconds and tripped the breaker. ANY SUGGESTIONS? I too think it might be a control panel issue also because it ran flawlessly prior to me turning the heat on then off again???????