Winterizing AC/Heater units

A

AllanS

Active Member
Oct 30, 2020
180
Boat Info
1989 440 Aft Cabin
Engines
Twin Caterpiller 3208 (375 HP)
Hi, I’m winterizing my three AC/Heater units for the first time, so I need some advice. I know how to feed the antifreeze up through the raw water strainer, so I’m good there. Here’s my question:

Normally, when I turn on the pump relay and any one of the AC/Heater units, water comes out three separate through-hulls. Does this mean that when I feed the antifreeze into the raw water strainer I only need to turn on one AC/Heater unit to flush antifreeze to all three units, or do I have to turn on all three AC/Heater units to make sure antifreeze gets to the water systems on all three units?
 
AllanS said:
Here’s my question:

Normally, when I turn on the pump relay and any one of the AC/Heater units, water comes out three separate through-hulls. Does this mean that when I feed the antifreeze into the raw water strainer I only need to turn on one AC/Heater unit to flush antifreeze to all three units, or do I have to turn on all three AC/Heater units to make sure antifreeze gets to the water systems on all three units?
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As long as a/f comes out all 3 thru hulls you are good to just run one unit. Running other units still just runs the same raw water pump unless a boat has separate ac pumps.
If you look at that other thread and pump or blow a/f through from the thru hulls, be sure the a/f comes out the thru hulls that you are not pumping thru or you may have to pump thru each thru hull. The lines to each ac unit branch off at the pump or somewhere else along a main line, pumping pink thru one thru hull doesn’t guarantee it will flow back thru another ac branch. The pink being pumped through the thru hull follows the path of the least resistance, right out the bottom of the boat through the seacock, especially if the boat is on the hard blocked bow high.
 
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Thanks so much! I was pretty sure I just needed to run 1 unit, but it’s nice to get the confirmation!
 
I use a hand transfer pump from the outside stick the hose in where the water comes out pump about a gallon of pick in and when it pours out the bottom of pick up outside your done go to the next if you have mutiple units been doing this for years with no problems
 
OK, ran into trouble doing what I thought would be an easy antifreeze delivery to the AC units. I opened the sea strainer, turned on the pump relay and salon AC unit breakers, planning to pour pink antifreeze into the strainer as the AC pump sucked it down, but the fluid level in the strainer remained unchanged. I could hear the pump and the AC unit run, but no fluid movement. The AC pump has always worked well…is the issue that I am on the hard instead of in the water? Help! I may need to resort to Todd’s method if I can’t get the AC pump to engage. I have three AC units.
 
It’s not catching a prime. That’s why most of us do it the other way.
If you are bound and determined to do it by running the pump, you will have to prime the pump and stick the hose from the strainer to the pump in a bucket of a/f. If the pump catches any air it will lose prime
 
I think you’re right about it not catching a prime. So what specific fluid pump works best for pumping the AF from the outside thru-hulls inward? Make/model?
 
We owned a ‘06 260DA. Went to HD and found a threaded reducer that fit the seacock. Put a 3/4” female garden hose fitting in the reducer. Put a 5 gallon bucket on the cockpit floor and connected a hose from the bottom of the bucket to the hose fitting in the seacock. Opened the valve in the bottom of the bucket up on the cockpit floor and gravity pushed the pink out through the thru hull fitting. Done.

Bennett
 
Success! Took you guys advice and pumped antifreeze into each through-hull on the hull, and that worked like champ! Pink came pouring out the inlet screen each time. All good, thanks!
 
AllanS said:
Success! Took you guys advice and pumped antifreeze into each through-hull on the hull, and that worked like champ! Pink came pouring out the inlet screen each time. All good, thanks!
Click to expand...

I have a 380 Aft Cabin with three AC units but water only flows out through 2 output fittings. I believe the salon and aft AC units flow out the same port side fitting. How can we be sure A/F is flowing backwards through both AC units as it may just take the shortest route.
 
Are you saying that when all three AC are running, water only comes out of two thruhull openings? Are you sure there are not three? If just two, pump antifreeze into each external thruhull separately so each gets back-filled. Plug up each external thruhull as you pump AF into the other just to be sure.
 
Jack380AC said:
I have an air compressor. Can I just blow out the lines in the reverse direction?
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You could. There's an inherent assumption, though, that ALL of the water is pushed out and doesn't "recollect" in a low spot somewhere. It's super easy and fast to pump the AF in and... leaves you with no assumptions. Quite honestly, it's faster and easier than dragging a compressor around on an extension cord, too.
 
Lazy Daze said:
You could. There's an inherent assumption, though, that ALL of the water is pushed out and doesn't "recollect" in a low spot somewhere. It's super easy and fast to pump the AF in and... leaves you with no assumptions. Quite honestly, it's faster and easier than dragging a compressor around on an extension cord, too.
Click to expand...

Good thought. I'm equally curious how I will be sure AF get to both ACs as there is only one outlet for them. The forward unit has its own. Have always done this from the strainer end and not had issues but that technique has been a royal pain.
 
AllanS said:
Success! Took you guys advice and pumped antifreeze into each through-hull on the hull, and that worked like champ! Pink came pouring out the inlet screen each time. All good, thanks!
Click to expand...
Exactly how I always did it.
 
Jack380AC said:
Good thought. I'm equally curious how I will be sure AF get to both ACs as there is only one outlet for them. The forward unit has its own. Have always done this from the strainer end and not had issues but that technique has been a royal pain.
Click to expand...
If two units share one outlet, yes, that is a valid concern, Jack. But, what part was a royal pain? Maybe we can fix that... unless the problem is the access to it. Although, that's where a 15-year old kid comes in handy :)

How soft are the hoses used in your system? If they're not reinforced, you could clamp them shut in a logical spot, one at a time. Or, can you (relatively easily) get to the spot, after the pump, where the hoses split and go to each unit (or at least somewhere after they rise from the pump and before they dip back down again)? It's a bit more work this year, but you could install shutoff valves in each hose if it's reinforced.

Does your strainer have a garden hose adpater... or can you get the cap that has the adapter for the model you have?

Oh... if reaching seacocks is (or will become) an issue, google for "seacock handle extension".
 
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I was contemplating adding a hose connection when I came upon this thread and it sounded easier to pump in reverse. Not sure where/how to get a hose connection for my strainer. Picture attached....
IMG_2463.JPG
 
I'm not sure who makes that one - maybe someone else an chime in. I don't think it's Groco, though - maybe Perko or Buc Algonquin. If you can find out, maybe they have a repleacement lid that has a hose connector on it... or get a bulkhead fitting and install it in the cap and make your own.

Or... just kind of thinking as I go here... with the lid off and the basket out, can you just jamb a hose (cut the metal end off) into the output side of the strainer? Make the hose just long enough to bring it up to the deck - or somewhere accessible well above the pump. Connect the hose with another fitting near the bottom of a 5g pail that you use for this purpose. Dump a few gallons of AF in the pail and gravity will help.
 
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