AC overheat

https://youtu.be/gZHSUl1sx88

So I'm getting a HP error on my Ac and very little water exiting outside the boat. Strainer clean.

I figured maybe something clogged intake at sea cock, but can't dive on boat. Blew back through sea cock with shop vac and got bubbles coming out of sea cock.

Does this look like a normal amount of water coming in an open strainer it do I still have a clog?

Sounds like your pump impeller is going out.

The water should be gushing out. You do have a clog or the seacock is not fully open. Try working the handle back and forth a few times, that might help to clear it.

Dammit! That's not the answer I wanted. Lol. Don't have another pump handy.

This is the pump


So that's a normal amount of water pressure coming in the strainer?

hmason said:

The water should be gushing out. You do have a clog or the seacock is not fully open. Try working the handle back and forth a few times, that might help to clear it.

Click to expand...

Ok. Will try that.

Figured my shop vac trick would have dislodged whatever but guess not.

That amount of water is way too small. It should, as I said above, be gushing out. You have a clog before the pump. The pump cannot efficiently suck water in, it pushes it out on the high pressure side.

Again it may not be a clog before the pump.

That white plastic housing on your pump holds the impeller. It could be going bad, or there is dirt or shells etc. jamming it up.

That looks like a single application 120 volt pump. You can probably get a wet end replacement, with gasket. Frankly I would look to replacing the whole pump.

But first check that it is the pump.
Close the through bull. Disconnect the hose to the pump at the through hull side. Then slowly open the through hull. If you get an appropriate gush of water then your source is fine.
You can also then connect the hose again. Disconnect the hose of the ac side of the pump and have someone turn on the ac briefly while you watch. Be on the cell phone to tell them when to turn it off. If you don't see a significant flow, it is your pump and in all probability your impeller.

I get no gush of water. Only a trickle.

cardude01 said:

I get no gush of water. Only a trickle.

Click to expand...

Where? When you disconnected the hose at the through hull side of the pump and opened the through hull?

Menzies,
Did you watch the video? He's got the top off the sea strainer and the through hull opened and little to no water is coming out. Could the pump be shot? Yes, but he ain't gettin no water to the pump. If he puts on a new pump and no water is supplied he will likely ruin a new impeller/pump.

Ok, that video means nothing. If the top of the strainer is at the same level as the water outside the boat, there isn't going to be much flow. IF the sea level is a couple inches above the strainer you will get all kinds of flow.

You may still have something clogging the through hull or the hose leading to the strainer. Put everything back together and disconnect the output hose of the pump, turn the pump on, and see if you have flow.

Ted

Its not the "impellor". Thats a centrifugal pump, no rubber impellor and very very seldom does the plastic impellor wear out. He just aint gettin no watta. Just pull the hose off the thru hull and poke it out with a wood dowel. Unless it has an external strainer, then your gonna need to clean that.

Stuck in water hose in it and that unclogged it. I guess the air from the shop vac was not enough.

Thanks!!

OC diver is correct, if the pump and strainer top is above the waterline you wont get any flow. But,,, I assume it was working before, and most boat builders are smart enough to put the raw water supply below the waterline. I would think that if it has been working and now its not, and the water flow is minimal, that its probably a restriction on the inlet.

I clean my strainer and exercise the seacock frequently, so when I encountered a high pressure fault on my 1-yr old A/C I was bewildered. It turned out to be a clogged condensing coil. There is a lot of silt and marine growth in my marina which passes easily through the sea strainer, but builds up in the coil. I now reverse-flush with water at 6-months and with Rydlyme at 12-months. The system is now 3-years old and cools like the day it was first installed. I called Dometic customer service who recommended the coil cooling regime for my area.

BTW, my sea strainer is about 1/2" below the waterline and looks just like the video. The flow is completely adequate when the pump is primed and running.

Good luck

Almost wants to make one feed the AC cooling from fresh water.... hmmmmmmm.

Switchover valve? Hmmmmmmm

oscar said:

Almost wants to make one feed the AC cooling from fresh water.... hmmmmmmm.

Switchover valve? Hmmmmmmm

Click to expand...

Well that's one silly way to waste fresh water.

cardude01 said:

https://youtu.be/gZHSUl1sx88

So I'm getting a HP error on my Ac and very little water exiting outside the boat. Strainer clean.

I figured maybe something clogged intake at sea cock, but can't dive on boat. Blew back through sea cock with shop vac and got bubbles coming out of sea cock.

Does this look like a normal amount of water coming in an open strainer it do I still have a clog?

Click to expand...

It should be gushing out.

Yeah. The thru hull was clogged with something-- never found out what. I had no baseline knowledge of how much it should gush. After I unclogged it the water was really gushing out if the strainer with the cap off.

Now I know!!

Hard to get enough knowledge so you don't go chasing the wrong problem down the wrong avenue.

I don't have any clamshells on my AC through hull. More than once I've had to extract a fish that took up residence in the hole.

First thing I'd do is get the entire system "acid" cleaned. There are DIY rigs you can do, or hire a professional. This is a regular maintenance item anyway. Next check the hosing between pump and condensing unit. Are there any dips? It should be uphill all the way. Otherwise you will be prone to air locks and loss of prime.

You can get pump refurb kits from Depco Pump in Clearwater, FL, as well as expert advice.

Really like the external strainer for eliminating that potential problem.



Ted

Had a jellyfish sucked into mine. That was hard to clear out even using a water hose. I have had jellyfish clog every through hull over several years for engine, and generator too.

O C Diver said:

Really like the external strainer for eliminating that potential problem.

View attachment 52323

Ted

Click to expand...

This seems like an excellent idea, unless it reduces water flow too much.

caltexflanc said:

First thing I'd do is get the entire system "acid" cleaned. There are DIY rigs you can do, or hire a professional. This is a regular maintenance item anyway.

Click to expand...

For CD:

Pretty easy to DIY. On an AC system, just pour the "stuff" into the sea strainer (valve on thru-hull closed) while your AC pumps sucks it through the system. Once the system is fully loaded, let it sit for however long the "stuff" recommends. Repeat if necessary, but when finished... close up the sea strainer, open the valve, fire up the AC to flush... done.


It's only slightly ore difficult to cobble together a recirculating system, but capturing AC discharge for recirculation doesn't seem worth the effort.... for an AC system.


I've used Rydlyme (the "stuff") but apparently Barnacle Buster, Triton Marine's product, etc. all seem to work fine.

-Chris

cardude01 said:

This seems like an excellent idea, unless it reduces water flow too much.

Click to expand...

They come in different sizes. That one (on my trawler) will work with 3" seacocks and over 60 gallons per minute water flow. Should be ok for your AC pump.

Ted

Oh yeah. That's big. Cool! Thanks!

ranger42c said:

For CD:

Pretty easy to DIY. On an AC system, just pour the "stuff" into the sea strainer (valve on thru-hull closed) while your AC pumps sucks it through the system. Once the system is fully loaded, let it sit for however long the "stuff" recommends. Repeat if necessary, but when finished... close up the sea strainer, open the valve, fire up the AC to flush... done.


It's only slightly ore difficult to cobble together a recirculating system, but capturing AC discharge for recirculation doesn't seem worth the effort.... for an AC system.


I've used Rydlyme (the "stuff") but apparently Barnacle Buster, Triton Marine's product, etc. all seem to work fine.

-Chris

Click to expand...

I happen to have a little Rydlyme handy. Think I'll do that.

The external strainers are great for engines, not so great IMO for something like AC that is used a lot when stationary. Even with anti-fouling applied, they are prone to barnacles and other growth. You can keep much of that at bay in an internal strainer by putting a small scrap of copper piping in the strainer.

Recirculating does a much better job of cleaning the AC system and depending on access to the condenser unit output, pretty easy to rig. You'd be amazed at the extra gunk it will get out once you think you've cleaned it the other way.

George is right. If you are going to use that style of strainer on an A/C thruhull I would use this type.