Air Conditioning Problem

[avazquez]

Ok...here is the problem.My sailboat has two a/c units. One 9000 btu's for the two aft cabins and another big unit for the rest of the boat. The small unit which is 9000 btu's I took it out and replaced the burned capacitor, cleaned it and painted it. Performed vacuum and replenished with refrigerant and reinstalled it.As soon as I start the unit the compressor runs perfectly, cools great but all of the sudden the compressor trips and stays off for some time. Then it starts again then goes down and so on. This happens even when the thermostat is at its coldest setting. I even disconnected the thermostat and had it direct. Even bypassed the high and low pressure switches. Someone told me it was a dirty salt water coil condenser. This guy told me to ru Drano through it.Please Help .......this is the caribbean and it gets HOT

[markpj23]

It does sound to me like the cooling water to the condenser is not getting through. Can you verify water flow when the unit is running? My unit does exactly the same when the cooling pump does not switch on.

[avazquez]

Yes there is condensing water going thru.......but maybe the heat exchange is not ocurring due to a dirty coil????I wonder if the Drano flush can be performed with the unit in place. By diconecting the inlet and with a hose adding the drano....... and then adding fresh water to drain the system......

[markpj23]

I'm not a big fan of chemicals clearing pipes - just doesn't seem to work well for me at all. Yes what you suggest is probably workable - but if you have too much flow through there you'll be wasting time. Ideally hand pump the solution into the condenser and let it sit for a while before flushing.

If at all possible - if you have a cruisair unit for example - run a fish tape through the seawater coil tube. Be careful because the freon tubing is of course inside the larger cooling water tube. If you can snake it through there then use a small bottle brush that you could pull through the unit. Big risk is of course losing the brush inside the unit - that would not be good.

Let us know how it works out...

[avazquez]

I'll give it a try.............but still I have my doubts as there is good flow coming out of the hull.......I suppose there must be a lot of scale in there......at least to make the compressor go down.........

[markpj23]

I'm no expert - but the only other cause I can think of is an overcharge of freon. Are you certain that you charged it correctly?

[avazquez]

I did not do it myself but I will check the pressures....