Cleaning A/C Cooling Lines

[Hampton]

Two of my A/C units share one pump. One line travels 5 feet to the salon. The other travels 30 feet to the forward stateroom. We have done a lot of medium-term living aboards and travels, so, I didn't keep up on my line maintenance. I have since used acid twice to clean the lines, and though I get black gunk and foam out of the forward line, the flow is a slow trickle. I have even shoved 1/2 (lengthwise) of a wine bottle cork into the outflow of the salon A/C to force pressure forward, and I've shot 2 corks a pretty good distance into the bay doing it.

Yesterday, I took the lines off of the A/C unit and the pump after trying the acid wash. I taped a water hose to the forward end and tried forcing water backward followed by hooking it back up and forcing water forward several times. I opened every bilge from the ER to the forward stateroom and used pliers to gently squeeze the line together. I got a couple of crunching sounds along the way after which more crap (including small shell creatures) came out into the bilge. There is even some sand in there. I checked for kinks - there are some restrictions, but nothing too significant. After 3 hours, I had intermittently good flow, so I re-assembled all and still have just a trickle. Flow through the A/C unit is good. Flow from the unit out of the side of the boat is good. It is definitely the line from the pump to the unit.

Come to think of it, those little critters look like some I've seen on Lake Michigan, maybe Zebra Muscles? This boat was on the Lake at the dealer for 2 years before I bought it. Maybe they're coming loose and creating a log jam.

I intend to buy a 25' 1/4" plumbers snake and snake the line next. This line is extremely tough - I don't think I'll hurt it, but even if I did, it doesn't really matter because the next step is to replace it.

 

[fwebster]

John,

Acid should eat away the "epoxy" the critters glue themselves on with. If you used phosphoric acid, next try muriatic and leave it in the lines a little longer. Another alternative is to rig a pump in the cooling lines to recycle the acid for a while.

 

[Alex F]

Two of my A/C units share one pump. One line travels 5 feet to the salon. The other travels 30 feet to the forward stateroom. We have done a lot of medium-term living aboards and travels, so, I didn't keep up on my line maintenance. I have since used acid twice to clean the lines, and though I get black gunk and foam out of the forward line, the flow is a slow trickle. I have even shoved 1/2 (lengthwise) of a wine bottle cork into the outflow of the salon A/C to force pressure forward, and I've shot 2 corks a pretty good distance into the bay doing it.

Yesterday, I took the lines off of the A/C unit and the pump after trying the acid wash. I taped a water hose to the forward end and tried forcing water backward followed by hooking it back up and forcing water forward several times. I opened every bilge from the ER to the forward stateroom and used pliers to gently squeeze the line together. I got a couple of crunching sounds along the way after which more crap (including small shell creatures) came out into the bilge. There is even some sand in there. I checked for kinks - there are some restrictions, but nothing too significant. After 3 hours, I had intermittently good flow, so I re-assembled all and still have just a trickle. Flow through the A/C unit is good. Flow from the unit out of the side of the boat is good. It is definitely the line from the pump to the unit.

Come to think of it, those little critters look like some I've seen on Lake Michigan, maybe Zebra Muscles? This boat was on the Lake at the dealer for 2 years before I bought it. Maybe they're coming loose and creating a log jam.

I intend to buy a 25' 1/4" plumbers snake and snake the line next. This line is extremely tough - I don't think I'll hurt it, but even if I did, it doesn't really matter because the next step is to replace it.

John,

After trying out Frank's suggestion I can't think of anything else but the snake.

Few things on the snake. I would get the round shape one (not like electrical snake that's flat). What I always do is bend the end making a small hook. I would tape some small piece of cloth or just make a small bubble out of the electrical tape on the end, use some lubricant (a simple dish soap can do the trick too). Send the soap first and then the snake. I think that you should be able to get the snake going almost to the very end as it should be fairly straight run. As I recall, the line goes from the A/C unit under in to the bow thruster compartment and from there it's a straight shot along the stbd stringer all the way to the ER. Then, there's one turn up in to the pump.

Good luck and let us know how it works out.

 

[Kendall]

My buddy had the same thing going on with the 4 AC units in his Cruisers Yachts sedan.... He had a guy come out and cycle a Barnacle busters type mix through the system for 8 hours and the zebras finally let go...

 

[docofthebay]

I did the pump it thru method that Frank refers to. I took the same Rydlyme that cleans the raw water system of the engines, and ran it on a loop for a hour. Had two small baitwell pumps mounted on a 5 gallon bucket going into both water exit thru hulls. This then emptied by the one line going into the AC water pump back into the bucket. I ran it backward to the normal flow direction. That way there is always fresh cleaning solution working on the gunked up areas and pushing it backwards away from the small tight areas. Worked great!

BTW, did both engines the same day for 4 hours each. Really cleaned them up as well. It is amazing the crap the will come out of the engines. ( and AC )

 

[Mike Blake]

John funny mine did the same thing on saturday after we got in. I did the phosphoric acid trick and all better. I'm down in Yankeetown on the withlacoochee river. I have to clean it 1 time per year.

Mike

 

[bahamabreisus]

Having the same issue with our 500DA. Starboard peeing like a race horse, port side, not so, Talked with local AC guy, he suggested hooking dock water hose to the beginning of that port side run ( a lot more pressure ) let it run for a couple hours. That will clean a lot of the junk out. Plan on doing this afternoon. Will let you know how it works

 

[fwebster]

Freshwater also kills salt water marine growth................

 

[Hampton]

I literally ran 250 gal of fresh water thru it backwards the other day. Will retry acid for longer. Was afraid of hurting system. Thought it was good to go. Not so much. I think I have a shell behaving like a check valve in there. Maybe I should turn the line around : )

 

[Hampton]

I was going to try recorking the salon and forcing more acid uphill but I think I'll start by using a funnel and pouring acid downhill before I try to set up a recirculating system. Then......the snake.

Thank you all very much.

 

[Hampton]

Freshwater also kills salt water marine growth................

Very true. Trust me...its definitely dead. I have left the system off for a week at a time several times this year after drying the cabin out thoroughly. When I do start it back up, the water coming out stinks to high heaven, but your point is well taken.

 

[Hampton]

I ran 25' of the 1/4" snake in from the pump up toward the bow. It got stopped a few times, but then I spun it and continued on. After getting to the end, I pulled it out and then took the line off from the A/C unit and ran the snake back the other way. It got stopped several times and took a lot of work to keep it moving. After reaching the end, 25' from the bow, I tried to extract it and it wouldn't budge. I poured soap in after it and added a few cups of water. No luck. Then, we hooked it back up at the pump and caught the water near the bow in a bucket, under the forward berth. Still wouldn't come out. I tried un-winding it, like backing out a screw, but that made the snake expand in the line, so, we added more soap, a little water, and screwed it in as if to make it go further while yanking the thing out aggressively. I stretched the snake about 10 more feet and then it let loose and came out.

I ran water from the pump into the bucket several times to get all of the crap out without clogging the A/C. It flows as well as the salon line now. The A/C absolutely freezes the cabin out too. That good ole delta-T equation came into play. Now, I plan to stay on top of the lines, though I swear that a lot of that stuff grew in fresh water before we bought the boat.

 

[peterkvs]

+1 for Rydlyme and setting up a circulation pump. The stuff is amazing and safe to dump in the water, so you can flush easily. I set up a circulation system on my twin cat diesels and flushed them both at the same time. The heat exchangers were about 30-50% blocked when I started and after a 4 hour flush everything was sparkling clean. Use a large bucket when you circulate because that stuff really reacts with the crap in the lines and causes a lot of foam in the beginning.

 

[Hampton]

+1 for Rydlyme and setting up a circulation pump. The stuff is amazing and safe to dump in the water, so you can flush easily. I set up a circulation system on my twin cat diesels and flushed them both at the same time. The heat exchangers were about 30-50% blocked when I started and after a 4 hour flush everything was sparkling clean. Use a large bucket when you circulate because that stuff really reacts with the crap in the lines and causes a lot of foam in the beginning.

I am interested in the details of this operation. What kind of pump. What kind of connections. My raw water lines are huge.

 

[docofthebay]

I used 3/4 inch ID clear hose as it connects to the pumps on one end and then experimented with PVC fittings to find one that fit the other end of the 3/4 hose then go into the engine water supply hose. Actually you connect the flow to the exhaust shower hose where raw water would normally enter the exhaust and flow backward through the entire raw water system and exits the hose here it would connect into the impeller pump. This then drains back into the bucket. I used 500 gph baitwell pumps. These plumb thru the side of the bucket to pickup the Rydlyme This sets up a reverse flow thru the engine. Needs to run 4 hours The clear hose lets you see all the bubbling and fizzing and crap coming out and also let's you know when it's thru as no more comes out and bubbles stop.

 

[Hampton]

Good info. I may build one. I would have to modify the concept. Almost all of my lines are about 3" SS, not hoses.

 

[peterkvs]

I posted how I flushed the system with Rydlyme at http://clubsearay.com/showthread.ph...Cat-3116-99-400-Sundancer?p=681001#post681001 Hope this helps. Pete

 

[vandal]

The best trick is 40 pounds of compressed air while pump is running and air blasts out all sand mud like you blow your nose.

 

[Hampton]

The best trick is 40 pounds of compressed air while pump is running and air blasts out all sand mud like you blow your nose.

How about a garden hose? That would work, wouldn't it?

 

[JVM225]

I clean mine out during my winterization with the boat up on blocks by wedging a section of garden hose (with the end cut off) in to the discharge and running fresh water through it. I remove the strainer before I start the process. After I run the fresh water through it I replace the strainer and then hand pump the pink stuff through the system using the same small section of garden hose wedged in to the discharge (which is now connected to a 5 gallon container) until I see pink stuff flowing out of the intake strainer on the bottom of the boat. The hand pump is hooked up in between the 5 gallon container, and the small length of cut off hose. The whole process is a one man job that takes about 10 minutes from start to finish.