Air Conditioner Flush

z28jimi

Member
Feb 10, 2017
69
Daytona Beach
Boat Info
2006 44' Sea Ray Sedan Bridge, Highfield dinghy, 2006 22' Pathfinder
Engines
Cummins
I'm going to get some Barnacle Buster to clean out my 3 A/C units. I can start the flow at the strainer with a purpose-made cap, but I can't disconnect the discharge hose at the thru-hull without contortions I don't think my body will stand. I'm sure the discharge hoses are gunked up too, and I hate to leave them out of the cleaning loop. Has anyone come up with a way to make a water-tight connection to the outside end of the A/C discharge so it can be run back to the Barnacle Buster bucket for recirculation? I'm thinking of something along the lines of jamming a tube into the discharge port, but that seems too simple to be workable. Any suggestions? What do you all do? Just leave that section of hose alone?
 
Maybe take the tube off the exhaust side of the AC itself.

The last time I did mine I used a 50/50 phosphoric acid (from Homedepot) to water mix and filled the system and just let it sit.

To fill I closed the seacock and fed in through a seaflush into the strainer. After sitting I just opened the seacock and started up the system.

Others (I believe @fwebster ) posted about hooking up city Water at the strainer to flush out under pressure.

-Kevin
 
When I winterized mine I just took a hose that fit my pump and held it tight to the thru hull with a small towel wrapped around it. I did spill some but it made it all the way through and out the pickup on the bottom of the boat.
 
I use a utility pump in a 5 gallon pail with a 1/2 inch diameter clear tube shoved into the ac discharge. Plug in the pump and run the pink anti freeze backwards thru the system. The easiest system on the boat to winterize.
 
Sometimes simple is good. I don't see anything wrong with doing that to flush the system. The biggest challenge (and it's not really that big) is making sure to secure the hose well enough so it doesn't pop out during the flushing time. You can use tape to make the OD hose diameter a little bigger, if needed. Put a nice, loose, loopy bend (enough that the bend doesn't stress the "hold" that the fitting has on the hose) in the hose as it exits the thru-hull and tape the hose onto the hull real well.
 
I use a utility pump in a 5 gallon pail with a 1/2 inch diameter clear tube shoved into the ac discharge. Plug in the pump and run the pink anti freeze backwards thru the system. The easiest system on the boat to winterize.

I think the OP said he wanted to use "Barnacle Buster to clean" his system not winterize - that is a different process.

-Kevin
 
Sometimes simple is good. I don't see anything wrong with doing that to flush the system. The biggest challenge (and it's not really that big) is making sure to secure the hose well enough so it doesn't pop out during the flushing time. You can use tape to make the OD hose diameter a little bigger, if needed. Put a nice, loose, loopy bend (enough that the bend doesn't stress the "hold" that the fitting has on the hose) in the hose as it exits the thru-hull and tape the hose onto the hull real well.

While the OP was looking to clean not winterize I will side note that I use a small red Harbor Freight hand pump with the tube going into the outlet port for winterization. I make sure the sea cock is open then hand pump air in to flush out. Then I pump through the pink AF until it runs pink out of the pickup then done. I did add a little electrical tape to the hose to snug it up real good. Uses about 1 gallon and takes at most 10 mins.

-Kevin
 
While the OP was looking to clean not winterize I will side note that I use a small red Harbor Freight hand pump with the tube going into the outlet port for winterization. I make sure the sea cock is open then hand pump air in to flush out. Then I pump through the pink AF until it runs pink out of the pickup then done. I did add a little electrical tape to the hose to snug it up real good. Uses about 1 gallon and takes at most 10 mins.

-Kevin
I use that same HF pump!
 
To keep my air condition system clean I regularly put bromine tablets in the strainer. It will kill biological growth that plugs up the cooling lines in my area. Not sure if that would work in your area.

MM
 
To keep my air condition system clean I regularly put bromine tablets in the strainer. It will kill biological growth that plugs up the cooling lines in my area. Not sure if that would work in your area.

MM

+1 I just started this year and it seemed to keep the growth down. I need to refill the strainer every week or so.

-Kevin
 
I made a contraption with a 5 gallon bucket and a rule 2000 bilge pump. I use phosphoric acid from Home Depot it’s called concrete etch and prep. Hook it to the ac discharge and to the the raw water hose in your bilge and it will make a complete loop. It takes about 90-120 minutes but it will clean the loop like new.

Josh
 
Be careful using chlorine or bromine based pool sanitizer pucks in sea strainers. The chemistry isn't compatible with Perko or Groco sttrainer baskets. They have plastic bottoms in them and the disolved pool tablets left in the strainer yields a very concentrated solution in the strainer that gradually dissolves the plastic. There is no fix other than a new strainer basket that costs about $60......$90 if you but the strainer repair kit.

If you use chlorine or bromine pucks in your strainer, be sure you continue to remove the strainer to empty it and check the bottom of the basket regularly. Don't get lulled into looking into the strainer, and thinking "Wow, this stuff is really working; there is nothing in here" because the bottom of strainer basket may be gone and you are just passing everything the basket would normally catch on thru the A/C cooling coils. Cleaning the entire system of grass, barnacles, minnows, shells, oysters, sea worms, etc. is a lot more work than cleaning the strainer regularly and occasionally cleaning the coils with phosphoric acid.
 
Be careful using chlorine or bromine based pool sanitizer pucks in sea strainers. The chemistry isn't compatible with Perko or Groco sttrainer baskets. They have plastic bottoms in them and the disolved pool tablets left in the strainer yields a very concentrated solution in the strainer that gradually dissolves the plastic. There is no fix other than a new strainer basket that costs about $60......$90 if you but the strainer repair kit.

If you use chlorine or bromine pucks in your strainer, be sure you continue to remove the strainer to empty it and check the bottom of the basket regularly. Don't get lulled into looking into the strainer, and thinking "Wow, this stuff is really working; there is nothing in here" because the bottom of strainer basket may be gone and you are just passing everything the basket would normally catch on thru the A/C cooling coils. Cleaning the entire system of grass, barnacles, minnows, shells, oysters, sea worms, etc. is a lot more work than cleaning the strainer regularly and occasionally cleaning the coils with phosphoric acid.

Thanks, our standard of practice is to remove the strainer and clean it as, even at 2 week intervals it usually has gunk it has filtered out, as we are in back flow river water (a dug out swamp). I will check for bromine residue as I have never noticed it when I clean the basket, which is usually done at the dock with a stiff bottle cleaning brush. Is there anything otherwise in the system that the bromine would harm?

MM
 
My diver said to ditch the chlorine and bromine tabs and use copper fittings from the hardware store. I put a few small copper elbow fittings in the strainer basket and it works like a charm. No growth for a year now in FL. I still have to flush the lines of muck that I pick up......but no more barnies in there.
 
My diver said to ditch the chlorine and bromine tabs and use copper fittings from the hardware store. I put a few small copper elbow fittings in the strainer basket and it works like a charm. No growth for a year now in FL. I still have to flush the lines of muck that I pick up......but no more barnies in there.

We may have different needs concerning what plugs our AC pump lines. We deal with biological growth and I have never even heard of barnicales in the Great Lakes. We do fight Zebra mussels, but they have not been an issue in AC pump lines for anyone I know.

MM
 
OK, interesting responses, but none that directly address my question. As I am located in Daytona Beach, winterizing my system is of very little concern. There is a flexible hose running from the raw water outlet of the A/C unit to the discharge through hull. My question is, how do you guys clean that section of hose when you do a Barnacle Buster treatment? In a perfect world, I'd take the hose off the through hull and stick it into the Barnacle Buster bucket thus completing the loop. My boat however, doesn't live in a perfect world. It lives in a world where only a rubberized midget can get to that particular through hull. So...my options seem to be: 1. Ignore that section of hose and hope it isn't too gunked up, or 2. find a way to connect a hose to the outside of the through hull and direct that new temporarily connected hose back into the BB bucket to complete the loop, cleaning everything from the intake to the discharge, including all parts in between. The missing information for the part 2. option is how to make a water tight connection to the outside of the through hull. Any ideas, suggestions, proven methods?
 
OK, interesting responses, but none that directly address my question. The missing information for the part 2. option is how to make a water tight connection to the outside of the through hull. Any ideas, suggestions, proven methods?

See my (and a few other's) response above.
 
If you absolutely cannot get to that hose... and you should even if its difficult, then just hook your dock water connection to that section and blow it out for 5 minutes. It's not as good as the acid but better then doing nothing.
 

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