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Old 22-10-2012, 05:20   #1
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How to winterized the marine HVAC

I need a couple of pointers please. A dummies guide to winterize the air conditioner.

I have - in order - thru hull, a filter, hose, an iwaki pump, t-vent for bleeding air, a/c coil, and finally more hose to a thru hull exit above the waterline. Unlike an engine, I can't figure out where i could just run it and pour non-toxic antifreeze into the system for various access, orientation and elevation reasons, so what tips do the forum have for purging saltwater from such systems? How is it normally done?

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Old 22-10-2012, 05:54   #2
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Re: How to winterized the marine HVAC

Assume the boat is out of the water. Disconnect input hose to iwaki pump and open intake thru hull and drain hose section. Attach a section of like hose to pump intake that will fit into the antifreeze jug. Start the iwaki pump and run until stream out of the exit thu hull turns to antifreeze. Reconnect hoses and you are finished.

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Old 22-10-2012, 07:12   #3
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Re: How to winterized the marine HVAC

If the boat is out of the water, I've heard you can also disconnect at the iwaki pump discharge, and use compressed air to "back flush" the system from the external discharge thru-hull.

If the boat is in the water... what's your "filter"? A sea strainer with basket? If so you can close the intake thru-hull open that strainer, and pour pink antifireeze in while the pump's running. Some juggling involved to not overflow, and also not lose prime.

Otherwise, you can close the inlet thru-hull, disconnect the inlet hose of the iwaki pump, and still use the iwaki to pump AF through the system.

Another option is to install a Groco flush adapter (aka safety seacock conversion) in line after the inlet thru-hull. The flush adapter essentiall gives you a built in T in the line, and you can use that (with thru-hull closed) to introduce antifreeze -- or even sediment cleaner, periodically -- into the system.

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Old 22-10-2012, 09:23   #4
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Re: How to winterized the marine HVAC

Don't know about Iwaki pumps, but March and Cal pumps won't pull a prime up to the suction of the pump if you just put the suction hose in a bucket of antifreeze.

So disconnect the suction hose at the filter. Elevate the hose above the pump and using a funnel pour antifreeze into the hose while running the pump. It only takes a few seconds to pull enough antifreeze in to get it coming out the side of the boat.

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Old 22-10-2012, 10:52   #5
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Re: How to winterized the marine HVAC

It is FAR better to install a few valves to simplify this process, to all water-based systems:Sail Delmarva: Easier Winterizing

Why this isn't factory, I've got no idea. Many northern sailors add this sort of plumbing.
"Climbing (sailing) is like fun, only different."

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