a/c problem

Hi,

You could remove the strainer top and using a rag to take up the slack use a hose with a slight flow to fill the system. When you see it or spmeopne can see it coming out the outer end stop it and close up the system again.

This should help to prime the pump if that's what it needs.

Please post back and let us know how you get on.

Hi,

I should have added close the SW inlet and make sure the OB Discharge is open when using the hose to prime the system.

If not the water you are adding might just flow out the inlet and not fill the rest of the system

Open the SW inlet before you crank the system up.

The raw water pump is working? Because mine froze up and no water flowed for me , so I sprayed wd40 and freed it

Are you sure the a/c pump is coming on? Try sticking a garden hose in the discharge water hull fitting on the outside of the boat for about a minute or two then turn the a/c on. Make sure the seacock's open when you do this.......but the waterflow might backflush the air out of it without having to touch anything.....

Normally If the sea-strainer is full of sea-water, I can get them to prime by moving around the hose going to the raw water pump so that it has no dips in it enough for it to prime.

Check the breaker for the pump too

That pump should also be below the water line and have a fully flooded suction side.

It sounds like you're air-locked. Mine do the same thing when I first open the valves. If you can't pressurize a bit from the Groco, let it bounce around in the slip a bit. Next weekend it will be primed. Works for me, hope it works for you. My pumps are all below the waterline. Also, at the compressor unit there is a bleed valve on the intake side if you can get to it easily.

If the hose from the sea-strainer has an upward angle to it all of the way to the pump, or no high/low dips in it, it will self prime usually.

Mine are a straight, short runs up to the pump, but I have long runs to the compressor which are difficult to overcome if those lines are cleared during winterizing.

If it took 3-5 minutes for water to come out, it sounds like you have a bad pump impellor, a blockage somewhere in the lines/system/sea strainer, an air leak, or something wrong. I would shut the system off, wait 15 minutes, turn the a/c back on and see how long it takes water to come out.

On mine the water pump does not come on until the compressor comes on if the temp setting is higher then the air temp water doesn't come on try lowering the temp setting

Ac 356

Sam,

My previous 356 had the same issue after a number of seasons. The impeller is probably gettting worn. The quick fix was to bleed the air out at the input side of the water pump until water dripped out. The next fix was to replace the impeller. Since it is easy to get to, either fix is not a big issue. I wouldn't let it run it dry though. It will overheat and shut itself down but that is not a good exercise for the compressor. BTW the forward AC unit drain and drain hose to the sump does get clogged from time to time so if you are seeing water in the forward bilge that would be a good place to check.

I had a hard time priming mine last week. I have 6 units on the boat. When I arrived for launch, the marina had already launched and started everything. MY mistake was assuming they had primed the air just because it was running.

The 2 bridge units worked fine. The 4 interior units ran (didn't shut off, which is what I'd expect if there was no water flowing). They just didn't produce any heat. At first I thought the water might be too cold (and I saw the compressors icing a bit). Then it dawned on me that the bridge was really warm (I thought maybe it was the sun, but it was really, really warm).

I went down and opened a bleeder screw on the pressure side of the pump, and got some air. I thought that was it, but no luck. Soon enough 1 unit started working. Eventually 3 of the 4 were working with really nothing more than me looking at them in confusion.

The last one wouldn't work. I took off the outlet water line (easier to get to), no water. I had to work to get the inlet side and there was air trapped in it.

I've always had trouble priming (and winterizing) the ac lines, but I figured that once I get the pump primed, all would be good.

I still don't understand this. Not sure if the pump is going (but the boat is a 2007, so I can't see that. My last boat was an 1989 and that original pump still ran like a champ).

I was actually thinking of adding a fitting/valve from the wash down to each of the ac units (right at the pump), so I can force the water into the system. I just don't understand why that would work if the ac pump won't (it's quite a large pump).

Anybody understand this better?

Take your boat for a run, or let it bounce around in the slip a bit. They will eventually prime. The natural force of the water coming in thru the thru hull does not have enough initial pressure to purge some of your systems of air. That's what was happening to the systems that primed themselves during your "confusion" otherwise you have to apply some positive pressure to the intake side of the system - usually thru the groco in the manner suggested by K1W1.

I don't understand why so many builders manage to mess up such a simple system! How hard is it to understand that there should be no high/low point in the water line! There is no excuse for that...

Rant over,

The first thing to check is that the hose run from the strainer to the pump is uphill with no high point to trap air, often the hose goes over a stringer then dips back down. If that a the case, you will need to relocate the pump unless you want to go thru the headaches every time.

What kind of pump do you have? I seen large cruisair pumps with corroded impellers loosing capacity over the years. March pumps don't suffer from this but i ve had 2 with cracked plastic impellers over the past couple of years although in both cases the rattle from the plastic bits was a telltale sign

Usually, high points in the line between the pump and the ACs should not be an issue

Also make sure you don't have any blockage at the thru hull. The most sneaky blockage is a plastic bag be auss when you open the sea cock and the strainer, water will come in just fine but once the pump kicks in the suction pulls the bag over the TH and it kills the flow

I ve also seen barnacle bits stuck before the strainer and obviously the good old masking tape left after painting....

Pulling the hose off the pump inlet can be hard but sometimes you may have to in order to make sure water is there

Back flushing and adding priming Fitting may do the trick but fix it right and eliminate high points before the pump. Properly installed you should never have to prime the system

Actually the intake side of the pump is quite nicely designed. It comes in straight and the run from the thru-hull to the strainer is about a foot, then the strainer is attached directly to the pump.

The intake side was not clogged and was definitely primed.

That's the confusing part. I figured once the intake side was primed, it should push whatever air was in the output hoses through. I was wrong. It just didn't have the power or whatever to get the air pockets through the AC units (they just sat there until I bled them (which is one royal pain - I had to remove the fwd AC unit almost completely to get enough room at the intake hose to get it back on).