Winterizing AC

[Capt’nKarl]

Good day Captains!

It's not quite time to winterize here in Florida but that day will be coming soon. I installed a marine AC unit this summer and have a question about preparing it for cold weather. Is it possible to "back-flush" the unit from the discharge opening, running the antifreeze backwards through the tubing, through the pump and then out the fresh water intake? Makes sense to me but wanted some outside advise.

thanks,

Capt'nKarl

 

[Irish Mist]

Not sure why you would want to do it that way ? It is easy to just let the system pump the antifreeze through from the pick up hose. Just let it run until you see the antifreeze coming out. I winterized my generator and A/C while the boat was still in the water by just turning off the sea-cocks and disconnecting the hoses.
Mark

 

[Barry Cohen]

Cap 'N Karl:

This year, I did it the way you propose and it worked fine.

 

[SGIDAVE]

Good day Captains!

It's not quite time to winterize here in Florida but that day will be coming soon. I installed a marine AC unit this summer and have a question about preparing it for cold weather. Is it possible to "back-flush" the unit from the discharge opening, running the antifreeze backwards through the tubing, through the pump and then out the fresh water intake? Makes sense to me but wanted some outside advise.

thanks,

Capt'nKarl

Hello Karl,

Yes, that should work.

The pump in the AC system is the type that will not self-prime and thus backward flow can occur easily. There is actually a 'magnetic' connection between the pump's drive motor and the impeller that induces flow. It spins the impeller like the little magnetic 'stirrers' we used to use in chemistry lab.

dave

 

[Capt’nKarl]

Oh, my bad. I forgot to mention my Ranger in on the trailer so it's very easy to access the outside discharge. Thanks for the replies. I'm not quite ready to winterize since I will likely be going out again before it gets freezing and will use the reverse cycle on the AC for heat. I keep the thru hull closed to keep water in the line since the AC pump is not self-priming. I won't drain the system to winterize until I put her up, hopefully a short winter season.

Cheers!

Karl

 

[knotflying]

That is exactly how I have always done it. Open the sea cock and pump the antifreeze until it starts coming out and your done.

 

[DBBRanger]

That is exactly how I have always done it. Open the sea cock and pump the antifreeze until it starts coming out and your done.

Mike,
Do you actively pump it or just let gravity work through a funnel? The funnel appraoch didn't work for me.

 

[Irish Mist]

This would be an easier one man method... if the boat is not in the water 🙂 . I would think if you tilt the trailer lots... gravity should do its job. Actually if you could insert a tight fitting hose in the outlet, you just need to elevate the container until it flows.. I never thought of trying this .
Mark

 

[knotflying]

That is exactly how I have always done it. Open the sea cock and pump the antifreeze until it starts coming out and your done.

Mike,
Do you actively pump it or just let gravity work through a funnel? The funnel appraoch didn't work for me.

I have a hand pump made for antifreeze. I bought a piece of plastic tubing that fits tightly into the hull fitting and attached the standard female water hose fitting on the end and screw that to the pump hose and pump away. I would not rely on gravity to help you. It has to run through the coil and past the A/C pump impeller.