AC cleaning?

I

interj

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I seem to get poor water flow through my AC unit. I replaced the pump 2 years ago but the flow did not improve. I have heard some discussions about running something through the lines to clear it out in case you have build up. On really humid days I ice up, I wonder if this is because lack of flow. I would like to see if I can fix something before I drop it in the water.

I boat in salt water and the raw water sent through could build up I assume. Anyone every do any type of maintianence on the system?
 
I have had a problem with poor flow on my forward AC. The flow is normally less than the midships unit andit wasnot enough to keep it flushed from gunk and growth. It would clog up from time to time and was a pain to clean out. I cut into te line after the midships AC and installed a garden hose quick connect. Now I hook a dockside hose to the forward AC to flush it when I clean the sea strainer and it really keeps it cleared out and flowing. My bat stays in the water through the winter and last spring the mud daubers had sealed the forward AC outlet but this worked to clear it out.
 
icing is due to lack of AIR flow, not water flow.

you do need to clean the raw water circuit and coils every 2 or 3 years, depending on where you are and how much you use your AC.

it's done by circultating a mix of Phospho (less corrosive than muriatic acid) and water, usually using a 5 gal bucket and a small pump. connect the pump outlet to the AC coil inlet, and the coil outlet back into the bucket. check the hoses between the seacock/strainer/pump/AC unit for gorwth and barnacle, clean or replace as needed.

check the scoop outside too if you loose water flow. plastic bags can get trapped there... iu usually have to go for a swim once a year to clear a plastic bag.. not fun in marina but better than replacing a pump for no reason !
 
Jeff, Pascal is correct about the coils icing up but for me at least servicing the raw water is more a matter of weeks than years. A lot depends on where and how the vessel is stored. Since mine is at a slip behind the house and it's fairly shallow the water gets hot and growth is rampant. I clean the raw water strainer once every week or so during the summer and flush the system at least once a month. You can flush several different ways depending on the number of AC units and ease of access to the strainer. With one unit I believe it's easier to remove the hose prior to the AC pump and using various adapters available at your local hardware store hook a garden hose up and let it run at pressure through the system. You can do this with the pump on if you want or if you think it will help clean the impeller.
My boat has two AC units and I simply hook up each system after the pump and flush with fresh water. If I let it go too long and growth accumulates in the lines I add a couple of cups of muriatic acid to the hose using a funnel and let it slowly work its way thorough the system. Works every time. The key is regular maintenance. Then again that is the key to a safe trouble free boat.
Mike, Palm Coast, FL '04 Regal 4260 w/VP TAMD75EDC's
 
Ok pascal, so if I understand, you are just running your mix through the AC unit, not the entire hose system.

Any specific instructions to improve air flow?

I do clean the filter after the raw water in take, I have not seen a problem with the intake it self clogging.

Mike, you are recommending running water backwards through the system, correct? Will this have a negative impact on the pump and impellor?
 
I looked up phospho on google, and what I found was good for cleaning...not for a boat, but for a part of the anatomy certain people are accused of talking out of.
 
sorry... Phosphoric Acid... not ospho which is a rust treatment.

how you rig it depends on your setup. on my boat, the 4 condensing units are in the ER so i can daisy cahin them and run the mix from teh pump outlet and recover rght there too. on a boat with all in one units, it's gong to be hard to return the mix to the the beginging of the system because of the distance.

i get about 4 to 6 weeks before i need to clean the strainer... I'm on the bay so water isn't as hot as in a canal and the slip is deep enough.

for cleaning the air hadnler, see the other AC thread, someone gave some good instructions
 
Get a real cheap plastic garden hose nozzle and unscrew the front part. When it comes off what remains is a tapered fitting that can be pushed into the hull outlet fitting of the AC line. A blast of water hose pressure pushes out a lot of junk. One of those tapered street sweeper nozzles may work too. It doesent have to be a perfect fit as there is a lot more pressure and volume from the hose than the normal pump. This is easier than acid flushing but that may also be required if barnacles are growing in the tubes.
 
Actually Ospho is mostly phosphoric acid.

"OSPHO is a balanced formula of Phosphoric acid, Sodium Dichromate, Surfactants, and Extenders."
 
"A blast of water hose pressure pushes out a lot of junk. One of those tapered street sweeper nozzles may work too. It doesent have to be a perfect fit as there is a lot more pressure and volume from the hose than the normal pump. This is easier than acid flushing but that may also be required if barnacles are growing in the tubes."

Barnacles are rarely the culprit. At least in the heat exchange tubes.

It's the mineral build up on the inside of the tubes that causes the problem. It inhibits the heat exchange process.

In other words, the mineral build up acts as insulation on the insides of the tubes.

Now if it's been years or never since you have had your system flushed out, than it can be well worth passing the acid solution through the whole system including all the raw water feed and discharge lines to clean them out as well.
 
quote:
Originally posted by Capt. Bill1

"it's done by circultating a mix of Phospho"

Perhaps you're thinking of: http://www.ospho.com/

You can get that at most any hardware store.

Click to expand...


Ospho is for a rust treatment, not for cleaning metal lines or any other type of line.

I use Ospho after sanding grinding off rust and before primer.

G
 
An A/C freezing up can also be a sympton of low freon.

G
 
Jeff, I'm not recommending running water backwards. By running water from just in front of or behind the pump you're going in the same direction. Backwards is OK if you want to flush the through hull which can be necessary if it's gets clogged. I have read of several folks who do however flush backwards and have made adapters to fit on the discharge outlet on the hull. I've tried it but it means I gotta get in the water and it never works good for me.
Mike
 
"Ospho is for a rust treatment, not for cleaning metal lines or any other type of line."

Well since Ospho is 75% phosphoric acid and there is no iron oxide to change to iron phosphate in you exchanger tubes all the phosphoric acid does is remove the mineral build up.

It works just fine. But deluted muratic acid is cheaper and works faster.
 
all i can tell you is that from time to time a sudden restriction happens in my AC and flushing helps. It does not remove deposits for that I also used phosphoric but a lot of sand and small stuff can accumulate. In my case especially in the forward AC which has the least pressure being further away. Some day i should increase the hose size but flushing is easy.
 
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