Mariner 350 AC unit best performance?

[amanphoto]

It's been record hot up here and my AC unit (16,000 BTU) just is not keeping up. 90+ outside (water is 80) and the boat is not cooling down. It cools to high 70's. It works, but just not cooling down the cabin. I would like the get this working the best it can.

I'm not sure if the water that the boat is sitting in is to warm for AC to cool efficiently. I took it for a ride into the lake and the boat seamed to cool a little better when I took it into the lake where the water was cooler. I keep the intake filters in the cabins clean and vacuum them off regularly. I've also replaced some of the duck work with insulated rigid duct work for better flow and R value. I have nice solid stream of water coming out AC through hull fitting.

I'm in fresh water. I keep the sea strainer clean. Last year, I connect the city water (garden hose) to the intake and flushed it out. Some brown water blow out, but not much. Occasionally I will drop a pool bromine tablet into the sea strainer and let it dissolve and flow through the units. I think this will keep any stuff from growing in the lines.

Today, Under the dashboard where the unit lives, I took the AC intake vent off and flushed the coils on the condenser. They where not to dirty, but some grime did come off. They do look cleaner.

My questions is, Since I'm in fresh water, do I need to do a descale flush on the water side of the system? Run some sort of acid through the water side to clean it out?

What else can I do to increase the performance?

Thanks for the info.

[bud37]

It sounds like your system is working fine and you have optimized it pretty well.....For what its worth mine is just the same, when it is like you say ......the radiant heat from the sun beating on the glass is just too much to overcome when the humidity gets that high like it has been....now if you were in insulate the hull and liner or add a second unit, like the optional ones for down south. IMO you have done a good job.

[km1125]

If you have an IR temp gun, take some measurements. Looking for inlet water temperature and outlet water temperature. Also, if you can measure the flow of water (if you can capture it in a bucket and measure the time it takes to fill??). Also measure air temp in and out of evaporator area. With those things you can get a calculation of how much capacity your system presently has and if it's running properly. What fan speed do you run on the evaporator side?

Funny timing because I was just chatting with a friend about adding a heatsink to the compressor to improve capacity on a similar unit.