Air conditioning raw water system maintenance

[Adalton]

I recently moved onto my boat full time and am therefore running the AC pretty much constantly here in Florida. What do I need to do to keep the raw water flowing freely. I've heard a lot of marine growth can accumulate in the strainer and lines. I've heard about using acid, bleach, or just putting a pice of copper pipe in the strainer. Anyone have any great ideas to keep things running smoothly?

[Capt.Alex]

There are several products that can be used to flush the system periodically. Acid works but can be a bit harsh on the system and dangerous to deal with. There are some descaling products that work well, one is called Barnacle Buster. Some people have had luck by placing bromine tablets (for swimming pools) in the strainer basket. I have not tried this, I would be afraid of long term corrosion issues. To avoid the problem all together you need to have your your system set up so that when the compressor cycles off it also shuts down the water pump">raw water pump. The interruption in flow will deter growth. If you can arrange the system so that most of the water drains out when the pump cycles off that will help too. In the Florida heat the system runs more often then not though, so you will most likely need to flush the system periodically. If you get a serious build up of mussels in the system, I recommend replacing all of the soft hoses (easier than trying to clean them) and doing an acid flush. To flush, get a submersible pump from Home Depot (used for fountains and ponds). Place the pump in a 5 gallon bucket half filled with fresh water. Disconnect the supply and discharge hoses from the compressor and plumb the submersible pump to discharge port on the ac unit. Run another hose from the supply port on the ac unit back to the bucket. Essentially you create a closed loop running the opposite direction from the normal flow of water. Start the pump and get a good circulation flowing through the bucket. Then slowly add acid to the mixture in the bucket. Run a weak solution through for a long period of time, or increase the solution for a shorter time. You may need to stop periodically and replace the solution if it becomes heavily fouled.
One of the many joys of boat ownership in Fl.

[djmarchand]

Bleach, bromine tablets and copper in the strainer all will help with marine growth. But your problem is probably as much with water scale as marine growth.

So first clean you system up well by circulating acid as Capt Alex says. I prefer Barnacle Buster, Rydlime, CLR, etc to muriatic acid as they are milder, safer and won't corrode the metal parts like muriatic acid will.

Once it is clean try the marine life killers. That may extend your A/C's performance.

[67Therapy]

How often is this treatment neccesary...Florida panhandle?

[ranger58sb]

Another descaling product is made by Triton Marine Products, and is said to be completely environmentally friendly. I've used it, and it works well.

Can't speak first-hand to Florida periodicity, but I've read where other owners (further south from the panhandle) have said sometimes up to twice/year.

-Chris

[sartorst]

The outlet on my a/c was high and on the dock side of the boat ,when I was to be away for a time I would back flow fresh water through the system and then turn off through hull and let that stand with fresh water in the system

[Tellie]

It may make a big difference where your boat is at. Here in Florida many people have their boats in the back canal systems where bottom growth takes off at an accelerated pace due to the huge amounts of nitrogen introduced through lawn fertilizer run off. Take a look at Bio-guard. We've put a lot of them in larger boats and I've seen it work pretty well especially for systems that run continuously.


Spectra Watermakers - Marine - Bio-Guard Water Treatment System

[Orrjames]

We just clean our strainer once a month and replace the intake hose leading up to the strainer as needed, you'd be surprised at what a big difference a new, clear intake hose makes....We are near Orange Beach, AL. Close to you. Sometimes the system has to work so hard it pops a breaker, then we know for sure the cleaning has to start! With good, clean intake equipment it runs great. I think all the pro-active chemical treatments would work but my time is too valuable to mess with all that crap, if you have easy access to your strainer then it's all good.

[Roy M]

Tellie, I will be purchasing a Spectra system in three months (after escrow closes). I found this forum using the search function, regarding the Bio-Guard unit. I am interested in this product for both my reefer cooling system and for the watermaker supply. What can you say about the Bio-Guard? Can one unit handle both needs?

[Pirate999]

Be careful what chemicals you use as it may react poorly with the ac. Don't know what unit you have but you could wind up with more trouble than just monthly cleaning and fresh water flush.

[gonesail]

i have cleared live shrimp and crabs out the AC strainer along with lots of seaweed and other nasty things. not sure how much of the finer stuff ends up in the AC cooling coil. the guys around my dock showed me how to backflush a clogged intake hose after the compressor overheated. this usually happens on the hottest and muggiest night of the summer.

[Tellie]

Originally Posted by Roy M

Tellie, I will be purchasing a Spectra system in three months (after escrow closes). I found this forum using the search function, regarding the Bio-Guard unit. I am interested in this product for both my reefer cooling system and for the watermaker supply. What can you say about the Bio-Guard? Can one unit handle both needs?

Good luck with your new Spectra when you finally get it. Always feel comfortable calling, E-mailing or PMing me anytime if you have any questions or concerns.
The Bio Guard has worked great over here on the East coast with preventing blocking growth in the AC cooling lines and is perfectly safe for your AC. The Bio Guard is not needed at all for a watermaker system because of the fresh water flushing which would kill and inhibit most growth that occurs in AC lines. I sell only a few a year of these Bio guards as I'm primarily a watermaker guy. But if you have any questions about the Bio Guard I can put you in contact with the right guy who installs a lot of these things and has more experience with them than I do. Shoot me a PM if you'd like his number.

[Roy M]

Thanks, Tellie! According to the Spectra website, the installation of the Bio-Guard is super simple, just put it between the seacock and the strainer, in a place that is visible to confirm that all is clear. I will definitely be installing one in my refrigeration line.
Do you know if there is any health hazard of using it in the raw seawater side of a galley pump?

[ranger58sb]

I hadn't looked at that Spectra Bio-Guard link earlier... but it now occurs to me to report our local A/C guys simply recommend dropping a small piece of copper (pipe elbow, whatever shape can't plug the system) into the A/C's existing sea strainer.

-Chris

[C Skip R]

I live in Central Fl and flush my AC lines normally every couple of years. If you should see a slowdown in the water discharge then that is a signal to clean or have them cleaned. Use the closed bucket system mentioned above works well. Muriatic acid works well. I now use a 20% mixture of muriatic acid and 80% water. Tried Barnacle Buster although it is not strong enough to clean out lines. Rydlyme works better.