Anyone having issues with water being too hot for your A/C to run?

[MarinAirNoWorky]

I have a Marin air AC, 6000 BTU, from a company in Miami. I bought it because it was advertised as nice and quiet and I liked the tech aspect of it. Basically it has a nice panel that you can buy a cheap controller for and control it from the Internet on your smart phone.

I am located in the Florida Keys and for the first year it worked great. However, last summer in August the water temperature rose above 90°. At this point, it was two years old, and even though I flush it out every six months, the suggestion was to get some muriatic acid and some barnacle buster and run it through the system. Even though it was a huge pain to do this in the water, because there's not much access to it or it's plumbing, I did it. This did not fix anything. A local mechanic suggested, venting out some of the refrigerant, surprisingly enough that did fix it for a week. The error message displaying was E4, which in my research showed a high pressure to high warning. I vented a little more refrigerant, and that did fix it again for a week or so. After that, I did not feel that I should vent any more refrigerant as the mechanic told me that I really should only be doing a quick vent, maybe two or three times, for less than a second. I have also done the book a test, and it passed with flying colors and has never had an issue with water throughput. It has a pump on it that is MUCH higher flow than required (came with the boat).

I got a portable AC that takes up way too much space and doesn't really fit and is a pain in the butt to route hoses but for a couple weeks or even a month it wasn't a big deal.

This year I had been searching for a portable AC that would fit under the table and not break the bank. I found a couple very expensive camping models but ultimately decided to go with a $400 one that did fit under the table that I wanted it to fit under
and I thought we were golden.

Well, with all things happening on this planet, it seems that the water in my canal as of yesterday is 91° and for some reason this unit just will not run when the water is around that temperature. Keep in mind it's 91° two or 3 feet down. So 93 at the top might be within the realm and the inlet for the AC is about a foot underneath the top of the water.

This is the unit in question:
https://www.marinaire.com/Marine-air...-p/msba6k2.htm

This is the circulation pump it is paired with.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

As you can see it is 100's of gallons more per hour than required by the manf. so I cannot see this being a water throughput issue and I HAVE run muratic acid/water and barnical buster ($$$) through it, recirculating for more than 60 mins.

So last year, as soon as the water cooled off, just a couple degrees to under 90 everything went back to normal and it worked all winter long.

My question to all of you is, do any of you have problems with water that is too warm for your AC to run?

I have not left the Florida Keys with this boat, so I am not sure if the waters you cruise in, even if they are more southern are warmer than here, or if this is a Florida Keys canal issue I can tell you that multiple people are commenting about how hot the water is and how early this is happening. So much so that a group of folks said they hopped overboard to check out the sandbar yesterday and pretty much hopped back in their dinghy because it was just too hot.

I've ordered one of these super small, portable AC units that are advertised for camping and Rvs which I'm sure will work just fine and actually it's kind of exciting because if it does work that means no more water will need to be circulating through anything as I'm not a fan of that to begin with. Having a 1200 gallon per hour pump running for the AC could easily eventually overwhelm both bilge pumps in my mind.

Happy Fourth of July, and please let me know your thoughts!

[Statistical]

Page 4 of the manual seems to indicate it can handle inlet water temperature as high as 95 degrees. It is possible the pressure is still too high for the ambient water temp.

The proper way to do this would be to use gauges to measure the pressure:
1) get a set of gauges and learn how to use them
2) hire an AC tech who will come with a set of gauges

In both cases refer to the high side and low side required pressure ranges on page 4.

On edit: looks like the system has built in gauges (that is unexpectedly nice). When it is running what is the high side and low pressure gauges reading.

When you say it won't run what exactly happens. It refuses to turn on at all? It runs for a few seconds but shuts down? It runs but never cools?

Understand that a supersized pump is not going to help. The water can never cool the system to below ambient. If ambient temp is 92 degrees you could get a water main pump capable of 200,000 gph and it simply can never cool it below 92 degrees. Once the outlet temp gets to within a few degrees of the inlet temp a larger pump is simply wasting energy.

[rslifkin]

I'd definitely compare the cooling water inlet vs outlet temperatures in the hottest water it'll run in (might need to test in the morning when the surface water is a little cooler). If you're seeing more than a few degrees of temperature rise, a bigger pump will help. But going bigger on the pump is a game of diminishing returns. Unless it's significantly undersized now, you're only going to gain a little bit (maybe 1 or 2 degrees of water temperature margin). With the pump you have, you likely have enough water flow unless there's too much plumbing restriction.

Is the unit cooling well right before it throws the error? And as Statistical asked, make note of the pressure readings as well.

[GreenWave]

To answer your question - YES, water that is above 90 deg will cause issues for most marine AC units. Only idea is to try and rig up a temp intake that you can stick further down into the water.

[MarinAirNoWorky]

Originally Posted by Statistical

Page 4 of the manual seems to indicate it can handle inlet water temperature as high as 95 degrees. It is possible the pressure is still too high for the ambient water temp.

The proper way to do this would be to use gauges to measure the pressure:
1) get a set of gauges and learn how to use them
2) hire an AC tech who will come with a set of gauges

In both cases refer to the high side and low side required pressure ranges on page 4.

On edit: looks like the system has built in gauges (that is unexpectedly nice). When it is running what is the high side and low pressure gauges reading.

When you say it won't run what exactly happens. It refuses to turn on at all? It runs for a few seconds but shuts down? It runs but never cools?

Understand that a supersized pump is not going to help. The water can never cool the system to below ambient. If ambient temp is 92 degrees you could get a water main pump capable of 200,000 gph and it simply can never cool it below 92 degrees. Once the outlet temp gets to within a few degrees of the inlet temp a larger pump is simply wasting energy.

Thank you for your post, unfortunately, the gauges are not built-in on the smaller one. I do have an AC person at the dock here with me, unfortunately, he has some medical issues and there's no way I would ask him to go down in this hot boat. However, your point stands and I will ask him if I can do it and figure out what is going on.

I did read the manual over last year and I thought I remembered seeing 93°. As the cut off. It's kind of hard to tell what the exact temperature is at the surface of the water versus 6 to 12 inches under but I do know that the depth finder that is reading the temperature is more like 2 to 3 feet under. Completely understand the ambient temperature, and how it doesn't matter how much water will go through, was just pointing out that this is not a water flow issue. Thank you again. I will try to get some gauges and check it out.

[MarinAirNoWorky]

Thank you all, I hadn't thought about rigging up an intake that takes in water from lower, that's actually a pretty good idea and I might try that. To answer the question of if it turns on and runs fine at first, the answer is yes. It will run for 3 to 5 minutes and have nice cold air flowing. Eventually shutting off. It will try two more times and then the E4 error will show up if you flip the breaker it'll do the same thing three times but it just seems like it's getting too hot. And too much pressure.

[ttex]

You are getting a high pressure error and you have a pump that you claim pushes 100s of gallons more water per hour than the manual asks for. It would appear your issue is self explanatory?

The pressure should be in a range. Not just higher than the minimum.

[MarinAirNoWorky]

Originally Posted by ttex

You are getting a high pressure error and you have a pump that you claim pushes 100s of gallons more water per hour than the manual asks for. It would appear your issue is self explanatory?

The pressure should be in a range. Not just higher than the minimum.

Sure, but it works fine the rest of the year when the depth finder is reading below 90 degrees.

[Statistical]

Originally Posted by MarinAirNoWorky

Thank you all, I hadn't thought about rigging up an intake that takes in water from lower, that's actually a pretty good idea and I might try that. To answer the question of if it turns on and runs fine at first, the answer is yes. It will run for 3 to 5 minutes and have nice cold air flowing. Eventually shutting off. It will try two more times and then the E4 error will show up if you flip the breaker it'll do the same thing three times but it just seems like it's getting too hot. And too much pressure.

That sounds like it is overpressurized but hard to say for sure without gauges ideally the unit would have both low side and high side port to allow measuring both high and low pressure but sometimes smaller marine units are designed semi-disposable.

The other possibility is it is properly pressurized but you are just running into the limit of what it was designed for. Air cooled AC units assume ambient could be 100, 110 even 120 degrees and are sized for that. Water cooled unit tend to assume a lower ambient.

Either way for temporary relief the trick of rigging a deeper intake should work. Even if it is overpressurized it seems like it is only slightly so which means lower temp would bring down the pressure enough to avoid high pressure cutoff. So if it will be some time before you can get a tech there I would do that. If it turns out it isn't overpressurized the temporary hack may need to be semi-permanent for hot canal days.

[MarinAirNoWorky]

Thank you again,
I suppose that will be the next step as far as the pressure goes. Even relieving a little bit of pressure three times seemed like a lot to me and I didn't want to have to go through the hassle of filling it back up. Your arm Has to bend in certain ways that made it OK to relieve the pressure but would be a pain in the butt to actually try to put it back in.

Happy 4th!

[Senojev]

We have 3 Cruisaire units and when the water intake Temperature gets above 85 deg. F performance drops drastically. This is very common.

[MarinAirNoWorky]

Still hot in the keys.. yikes. Even portable AC's are having trouble.

It's not that the performance drops - it's that it goes to zero. Going to have to come up with an inlet hose that drops down deep, as suggested earlier in the thread.

[Talk Story]

Maybe get some shade cloth for the boat, it is the very hot time of year.

[Bowdrie]

I've read reports lately of the water in the Keys getting well over 90F.
At those temps the units simply are overpowered, they can't get a low enough condensing temp and that drives up the head pressure.
Short of rigging up some kind of hose that will reach down deep to cooler water there's not much else you can do.
Be advised that a convoluted hose run will require priming, you can't allow any air in the runs.
Something like a "water puppy" pump may be needed.
Don't keep letting out refrigerant.
While it drops the head pressure, it also drops the suction pressure and that reduces the gas return needed to return the oil, it also reduces the cooling of the compressor.
The compressor uses the return gas for much of its cooling.

[MarinAirNoWorky]

Thank you, yeah, I wasn't going to be letting anymore out. Prob let too much out to begin with. Here's the water temp from yesterday. Yes that says 93.

Going to try and rig something up today to get water from deeper in the canal.