Cheap AC mods/tricks we all need to know

J

JMS

Member
Jul 21, 2016
37
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Boat Info
2000 380 Sundancer & 2003 38' PowerPlay SS
Engines
7.4 Horizons 380hp / 572cid/750hp custom built 2x, Bmax drives
I thought I'd share a couple of AC mods/tricks I learned long ago.

1) Keeping water out of the condensation pan. If the pan isn't mounted just right water will sit in the pan causing it to rust and or overflow causing moisture on your cabin floor. I use a chemical injector from a pressure washer. Dema 204c works the best. I purchased mine from a car wash supply house. Dultmeier Sales has them online. I modify by removing the check ball. Install the largest office that comes with it. This device is installed inline on the discharge hose for the AC cooling water. Install after the AC unit. The small line of the top the, the injector hose is placed in the condensation pan wherever there is the greatest pool of water. The hose will have a suction on it whenever water is being discharged overboard. I adjust the flow screw about 3 turns out. It will keep the pan complete water free. (See pics)

2) Discharge port insert tube. I hate that nasty brown stain on the side of the boat below the AC water discharge thru hull fitting. If you take some 1/2 od plastic tubing, I use a 3" piece. Wrap a couple of turns of electrical tape around it and then push it firmly in to the thru hull fitting leaving about 1" sticking out from the fitting, water will shoot away from the hull and none will dribble down the hull so you won't get that tea cup stain.
 

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Parts for both mods should run about $55
 
My 2005 390 Motor Yacht has four separate AC systems, but it's been very hot lately and they seem to just barely keep up. I just bought the boat recently so I don't know if it's always been like this or is the result of reduced AC performance, due to seawater fouling of the condensers or perhaps the refrigerant is low. Anybody have any tips for cleaning the seawater side of the AC systems with Barnacle Buster or whatever?
 
While not a trick or mod, a useful feature that a lot of people are unaware of:

Cruisair (and probably others) have a humidity setting that is a must in my opinion. By default it runs the blower for 20 minutes and the A/C for 10 minutes every 12 hours. That setting is modifiable. I set it every time I will be gone from the boat for a day or more.

On a Cruisair panel, you hit the HEAT-COOL-FAN buttons simultaneously to engage it.
 
On the black part where the small suction tube connects there is a small straight blade screw that adjusts the flow. I'll get some installed pics next time I'm at the boat.
 
Joel_MD said:
My 2005 390 Motor Yacht has four separate AC systems, but it's been very hot lately and they seem to just barely keep up. I just bought the boat recently so I don't know if it's always been like this or is the result of reduced AC performance, due to seawater fouling of the condensers or perhaps the refrigerant is low. Anybody have any tips for cleaning the seawater side of the AC systems with Barnacle Buster or whatever?
Click to expand...

I'm south of you in RIC and not having such problems. IF it is fouled innards, flushing is easy and can be made inexpensive.

BB is very expensive phosphoric acid. Check the ingredients and the concentration in the MSDS.

Roughly a 17:3 (quarts) ratio water:acid will yield the same thing.

Mix the solution in a 5 gallon bucket.

If it is going to be an annual maintenance item, "T" into the RWC line before the unit and before the pee hole. Put a cheap utility pump in the solution and run it to one "T". Run a hose from the other "T" back to the bucket. Let the solution circulate for about 3-4 hours per system.

Rinse with fresh water. See how that works.
 
I posted this 4-5 years ago, so here is a re-run:

FAQ – Cleaning Air Conditioning Lines




Put a T in the line between the seacock and the strainer .........the strainers usually have an ell on the inlet side, remove it and replace it with a 'T"....put a ball valve and a hose connection on the 3rd side of the "T". When you flush with just freshwater, hook up a hose to the T and let her go full stream. Since the pump has a magnetic impeller, it free wheels with the flow from the hose. The added pressure from the "city" water hose will flush most of the crud out of the system and any that it won't flush is from marine growth adhering to the inside of the lines which requires an acid flush to clean out.

A lot of people use muriatic acid, but there are risks, particularly with older A/C units. Muriatic acid can erode the solder joints in the cooling coil, so if you use it, you may develop some leaks. Most A/C guys will not repair cooling coil leaks because it is a sign that the entire system is borderline. The other issue with muriatic acid is avoiding the fumes while you are doing the work.

It is much safer to use phosphoric acid for coil cleaning. It is milder and won't attack the solder joints. Many paint stores sell it as a surface prep for etching. Look for Prep-N-Etch, a Klean Strip product sold in the big box home stores:

http://www.kleanstrip.com/product/phosphoric-prep-etch


I use a 50% solution of phosphoric acid and water and just run it thru the system out of a bucket........when 2 gals of diluted phosphoric acid in pumped thru, (I have a 450DA…..others may take more or loss) shut down the system and let it sit for about 10 minutes, then start the system up and flush it with freshwater.

Use a tub or bucket with a drain out of the bottom or use a small water pump and pump your cleaning solution thru the air conditioning cooling system. The air conditioner can be on or off. If your a/c is flowing some water you can use the onboard circulating pump and let the system pump your acid solution thru the system. If it isn’t flowing, you need to remove the cooling lines from the circulating pump manifold, by-pass the circulating pump and use some other pump for cleaning the lines.

Tricks/disclaimers:

1.The above method flushes “the short way” since it doesn't require disassembling anything, makes no mess in the boat and is much easier than getting to the a/c outlets with a hose to back flush. However, you must clean the system before it gets so clogged up that water won’t flow thru the cooling coil and discharge out of the side of the boat.

2. Periodically flush the cooling system with fresh water at city water system pressures. Chlorinated freshwater will clear most normal algae and sludge.

3. Clean your a/c sea strainers weekly

4. Do not try to do clean the system with muriatic acid.

5. If your system is really dirty and because of the risk of dealing with acid, it might be best to hire a professional to come and do it for you while you watch him so you can do it the next time.

6. Replace the ell on the inlet of your air conditioning sea strainer with a bronze T. That makes the cleaning and flushing process one of the easiest boat jobs to do.
 
JMS said:
I thought I'd share a couple of AC mods/tricks I learned long ago.

1) Keeping water out of the condensation pan. If the pan isn't mounted just right water will sit in the pan causing it to rust and or overflow causing moisture on your cabin floor. I use a chemical injector from a pressure washer. Dema 204c works the best. I purchased mine from a car wash supply house. Dultmeier Sales has them online. I modify by removing the check ball. Install the largest office that comes with it. This device is installed inline on the discharge hose for the AC cooling water. Install after the AC unit. The small line of the top the, the injector hose is placed in the condensation pan wherever there is the greatest pool of water. The hose will have a suction on it whenever water is being discharged overboard. I adjust the flow screw about 3 turns out. It will keep the pan complete water free. (See pics)

2) Discharge port insert tube. I hate that nasty brown stain on the side of the boat below the AC water discharge thru hull fitting. If you take some 1/2 od plastic tubing, I use a 3" piece. Wrap a couple of turns of electrical tape around it and then push it firmly in to the thru hull fitting leaving about 1" sticking out from the fitting, water will shoot away from the hull and none will dribble down the hull so you won't get that tea cup stain.
Click to expand...

Nice find...I've used that system on my last boat because, I didn't have an easy path to the sump box or bilge to drain.

Be sure to put a filter inline before the injector part and clean it often to prevent overflows.
 
Not sure I would use a brass part in a saltwater environment. If that brass part corrodes and fails, the air conditioner pump will put a lot of water into your boat. I wonder if you can get one made of bronze?
 
Install pic
 

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Just installed my condensator yesterday. Works great. Much better than pouring all that water in the bilge.
 
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