Marine Air Systems A/C

[Doorpro]

Originally Posted by captainjay

It is also entirely possible that the High Pressure switch is bad.

Would it still work intermittently, because although it wouldn't fire up yesterday it has run flawlessly today.

[pbbmorton]

Canibul, you don't let it set. Rather you circulate it.

Mix 25% solution on mutiaric in 5 gallon bucket. Hook up the ac intake to a small bilge pump sitting in the bucket. Change the exit hose to come back to the bucket. Then the pump on. Let it circulate till it comes out clean. You can do it right at the unit.

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[transmitterdan]

Originally Posted by Doorpro

Would it still work intermittently, because although it wouldn't fire up yesterday it has run flawlessly today.

Yes, a pressure switch can be intermittent. But so can other things in the system. Gauges and someone who knows what the dials mean will tell if the pressure switch is right or not.

[DeepFrz]

You could also have a bad wiring connection to the switch.

[CarlF]

While muriatic acid (hydrochloric acid) has been used for years, it is about as dangerous a chemical as you can buy at a Home Depot. The fumes are especially dangerous inside the confined space of a boat.

I've decided it's not worth the risk and use Barnacle Buster. It works slower but the fumes won't burn my lungs.

Barnacle Buster ® Ready to Use | TRAC Ecological

[pbbmorton]

CarlF
A 25% solution is not toxic or dangerous. You do have to be careful but not a major problem. Marine AC techs use this method
Barnacle buster, while affective may not remove all of the types of material that can cause a blockage.

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[Canibul]

When I see "Barnacle Buster ® is a safe, non-toxic and biodegradable..." that pretty much tells me what I need to know about it. Besides, I'd have to import it. Nobody would stock it here. We want toxic. Toxic works. Muriatic acid, I can find.

[transmitterdan]

I don't have a label in front of me but I think Barnacle Buster is a diluted acid. Their labeling notwithstanding.

[ranger58sb]

Originally Posted by DeepFrz

By doing this how can you be sure each system gets cleaned? Your solution may be the reason he can't even blow air through the cooling coils of the problem unit.

Couldn't be sure from a distance, but OTOH I know it worked easily for our systems (one pump, two ACs, two discharges).

I just made sure descaler solution was coming out of each discharge before stopping the pump. It happens our AC discharges are on an "uphill" slope just before each discharge though, so the discharge hoses were mostly full of solution too, once pumping stopped.

-Chris

[mannix2]

I may have misspoken. My suggestion does not apply to the newer digital controls. My unit is older model with manual controls. There is a "Push to Reset" CB on the panel that must be used to override an HPF fault. I replaced the CB after all of the flushing and pump machinations failed and all is well. With all that you have done already, it is hard for me to believe that the problem is water related. But, as I have already demonstrated, I've been wrong before.

[CarlF]

Barnacle Buster is mostly phosphoric acid. It gives off no hazardous vapors. It's in Coca Cola. It takes longer than HCL but gets the job done with much less risk (you just circulate it longer). I expect you could just buy a jug of phosphoric acid and get pretty much the same results.

Muriatic acid (including when diluted to 25%) is most definitely not "safe" within the confined air space of a boat where the extremely dangerous vapors can concentrate. The more you dilute it the safer it gets (do the mixing out on the dock not in the boat) Can it be used with care by people who know how to handle it - sure.

Health Hazards
Muriatic acid and hydrogen chloride
vapor are highly corrosive. If a small quan-
tity of acid reaches the eye and is not
flushed out immediately, it can result in
damage that may reduce vision permanent-
ly. In contact with the skin, muriatic acid
causes severe burns unless washed off right
away. Swallowing muriatic acid causes
severe burns of the mucous membranes of
the mouth, esophagus and stomach and may
be fatal.
Inhalation can cause irritation to the
upper respiratory tract. The maximum
allowable concentration of hydrogen
chloride vapors is 5 ppm for an 8-hour
day. A concentration of 50 ppm cannot
be tolerated for more than one hour.
Concentrations of 1500 to 2000 ppm are
lethal in a few minutes.

[DeepFrz]

ranger42c, that was the part of my post that was confused with the other thread. Sorry for the mix up. On the other thread the OP said he couldn't blow air through with an air pump.

[ranger58sb]

Originally Posted by DeepFrz

ranger42c, that was the part of my post that was confused with the other thread. Sorry for the mix up. On the other thread the OP said he couldn't blow air through with an air pump.

Ah. Right with you, now.

-Chris

[Doorpro]

Ok Guys,

for the third day in a row I have 100% AC with no faults and cool cool air. Im just running the one unit because when more than one is on I cant tell when the pump switches off.
So, today I waited until it was in the mid 80's to switch the unit on and see if the problem was overworking it to help cool the galley (this is the galley unit) and I was expecting a HPF to be thrown but so far so good.
One thing does come to mind and it is pretty far fetched but who knows. You see when I removed the hose from the unit that would flush through the hull I attached a hose to the dock so I wasn't seeing what came out originally so who knows there may have been an obstruction that got blown out and I know this is very unlikely but hey, I've got a cold galley so I want to thank everyone that got involved and believe me when I tell you that every reply helped me, so thank you all. Watch this space, i'm still not convinced.

regards,
Doug.

[Canibul]

Okay, phosphoric acid. I can get that. So often these products consist of one active ingredient, and a bunch of marketing. I buy oxalic acid to get the rust stains off, but Naval Jelly is also basically phosphoric acid with a bunch of gooey stuff added.
I think Ospho is basically phosphoric acid. Barnacle Buster is probably just diluting it down for you.

We don't have EPA or other environmental regs here, so I can buy gallons of muriatic or phosphoric acid off the shelf.

As was said, some care needs to be taken when handling it, and disposing of it. But that's okay. My generation grew up learning to handle and respect acid.