Flushing AC line

[gerryb]

This months boating magazine has an article on flushing out your AC lines to kill any growth, scale, etc. The process involves a bucket of chemicals that gets circulated through the system's water lines. I don't know of anyone at our marina that does that. Anyone here include that in their maintenance schedule?

I do run the AC for a day or so each month in the summer using a chunk of chlorine in the water basket. Seems to work for us.

 

[earthmover17]

The same stuff that wants to grow on the bottom of your boat will grow in your AC lines.
I also use a chlorine tab in my strainer and have yet to have a problem. But I use a tab every 2 weeks.
If you don't use the tabs you would have to flush it.
Flushing in the long run is probably better but I'm lazy.

Jack

 

[fwebster]

I'm in a warm salty environment and I flush my A/C cooling coils annually with diluted phosphoric acid.

 

[trit21]

Frank, what is the method you use to flush the system out? Do you have a separate pump setup and recirculate the phosphoric acid ? Thanks for the reply. Pics if you have any.

 

[Four Suns]

I flush mine out about every other year... I use Rydlyme.

http://www.rydlyme.com/home.html

I love that stuff... Between that and BOEshield T9, life is good.

For the AC lines, I have one of these mounted at the seacock:

I have a bucket with a ball valve feed at the bottom and close the sea cock and plug the bucket in... At the AC unit, I disconnect the raw water discharge and hook a hose to it and feed it back to the bucket... and pinch off the other AC units dishcarge... then turn the AC on... let it run for about 10 minutes... turn it off... let it sit for about 30 minutes... let run for about 5 minutes and proceed to the next unit. Make sure you have a big bucket and don't fill it up. The stuff foams like crazy (think adding vinegar to baking soda).

Doing rydlyme on the engines is harder as you have to have an external pump...

 

[At Ease]

Those of you who use chlorine in the strainer, is that just a chlorine tab that you would use in a pool?

 

[Vince_nj1]

Those of you who use chlorine in the strainer, is that just a chlorine tab that you would use in a pool?

That seems like an easy fix, but won't the chlorine corrode things?

 

[osd9]

.... and pinch off the other AC units dishcarge... then turn the AC on... let it run for about 10 minutes... turn it off... let it sit for about 30 minutes... let run for about 5 minutes and proceed to the next unit. ....

I'm not sure I understand this portion of your flushing technique.

Are you talking about proceeding to the next raw water pump or the next AC unit off of the same raw water pump? Why "pinch" off the other units discharge? Why not just run it back, with a Y to the bucket and do both at the same time? If you are only 'pinching' off the discharge of the second AC unit off of the same pump, won't it cause an error message and shut down the pump for lack of flow? And, since you are only 'pinching' off the discharge, doesn't it's system fill with the solution up to the discharge? btw...how do you 'pinch' off the discharge?

Maybe I just need more coffee or something.....

 

[earthmover17]

The chlorine tabs are the same as the pool store sells. I prefer the 1 inch ones. The only issue is you will eventually eat a hole in your strainer basket. I usually put them in when we are at peak usage on the air units as to not let them sit.

Jack

 

[Turtlesboat]

Thanks, you just reminded me to get some more tabs. I get the big ones and cut them into quarters.

 

[osd9]

Gary....is this representative of what you are doing?

 

[Four Suns]

Gary....is this representative of what you are doing?

Yes...

I don't actually pinch the line... I pull it off and have a 2" long stub hose that I put on to block the flow.... same thing though.

And to answer your other "non-coffee" questions, you only turn on the AC unit you are flushing... or you will get an error message and the unit will shut down.

I have 3 units on one AC pump and a single unit on a single pump and do each circuit separately (4 total) just to make sure if one has more blockage, it doesn't mess up the flow and stay blocked... Plus I'm too damn cheap to buy 200' of 5/8" hose to do them all at once...

 

[firecadet613]

How quick does that chlorine tab dissolve? If I run my AC all day will it be gone by the end of the day?

 

[fwebster]

Don't your guys have seacocks on your A/C discharge lines? The 450DA's do.....to flush one but not both units, you just close a valve.

I use Gary's bucket method, but the timing is different. I use 40% phosphoric acid mixed with equal parts of water then run it thru with the A/C pump. When the bucket is empty, I shut down the A/C's, wait 3-4 minutes and turn 'em on and let them run the rest of the day.

 

[Four Suns]

Don't your guys have seacocks on your A/C discharge lines? The 450DA's do.....to flush one but not both units, you just close a valve.

I use Gary's bucket method, but the timing is different. I use 40% phosphoric acid mixed with equal parts of water then run it thru with the A/C pump. When the bucket is empty, I shut down the A/C's, wait 3-4 minutes and turn 'em on and let them run the rest of the day.

I'm not sure what is right for the "timing"... I just "wing it" based on when the stuff stops foaming.

The only unit on my boat that has a seacock on the discharge is the front master one. The rest go to a "common drain" system that all comes out the back end by the port exhaust tube. It's basically a 20' PVC pipe about 4" in diameter that all the boat's gray water and AC lines plug into.... hence the need to close off each unit.

 

[Alex F]

The same stuff that wants to grow on the bottom of your boat will grow in your AC lines.
I also use a chlorine tab in my strainer and have yet to have a problem. But I use a tab every 2 weeks....

Jack,
Can you explain how you do it? Is it something as simple as closing the a/c seacock and just dropping the tab in to the basket, close everything, open seacock and let it sit for some time? Did I miss anyting? How long do you wait before turning the a/c back on?

 

[billnpat]

Thanks, you just reminded me to get some more tabs. I get the big ones and cut them into quarters.

How do you know when the system needs flushing??:huh:
ours runs very well now, but i would want to get a jump now on any future problems

Where do you put those tabs (clorine)

 

[osd9]

I use the chlorine tablet in the basket flush. I use the cheapo quick disolving tablets and I break a half tab into smaller pieces before putting the pieces in the ac strainer basket. I shut the seacock and then hook a garden hose to the top of the strainer basket and let it run a for a few hours while I putz doing other stuff around the house/yard/boat. I don't know how well it works except to say that I don't have a flow problem. If the entire tablet didn't disolve when I need to shut down the water flow, I throw away the remaining pieces so that they don't lay there to further corrode the basket. The last thing I do is reopen the seacock and turn on the ac units to make sure everything is working fine.

 

[Alex F]

Dom,

Can you clarify the part when you hook up the garden hose. Does it mean that after placing the tablet you turn on the A/C and using fresh water the system gets flushed (running by getting cooled with fresh city water and disolving the tablet) for couple of hours?

 

[osd9]

Alex;

I have a flushing cap on top of the ac strainer housing.....

....... I do not turn on the ac system while flushing with the chlorine tablet. I just let the fresh water run and disolve the tablet......nice high pressure from the garden hose...