Why Disconnect Hose When Winterizing AC?

[Bosn Mate]

First time winterizing today. All went well until I tried the air conditioning - poured antifreeze in the strainer but no overboard discharge. I then remembered reading to disconnect the hose to the pump, insert funnel and pore antifreeze; overboard discharge achieved!!!!!

Appreciate if someone could explain why this occurs. In my simple mind, I don't have to do this when the boat is in the water so why can't I just put liquid in the strainer on land??????

Thanks for helping me understand this mystery.

 

[Eric R]

The AC pumps aren't self-priming, so sometimes it takes lifting the hose higher than the pump itself to get it to start pulling water, or in this case, antifreeze. Normally when the AC is pulling water, you have the strainer which is closed and a seacock open. The pressure from water pushing up from under the boat is enough to get it going.

 

[Bosn Mate]

That makes sense.

Thanks for clearing this up!!

 

[knotflying]

If the boat is on the trailer you can open the sea cock and then pump antifreeze into the discharge thru hull and it will then run out the pick up. I made an adapter on the pump hose that snug fits into the thru hull so pumping the antifreeze in is not a messy operation.

 

[rpmerrill]

I made a PVC standpipe (maybe 1-1/2 dia) about 18 inches tall. With a small rubber doughnut at the bottom (garnered from the aisle with plumbing stuff at Lowes) it is not a perfect fit but good enough to get the pump primed. I take off the strainer cover and insert the standpipe. (Seacock closed) Turn on the AC and pour in the antifreeze. Once the pump primes you're off to the races. You get some antifreeze in the bilge but you've gotta do that anyway.


When you're done a put the strainer cover back on!

 

[BB marine]

This devise is made from using half of the devise below (link) and bending the wire rod to make a hook to attach to the grate on the thru hull fitting on the bottom of the boat.

https://cdn3.bigcommerce.com/s-6rtev5ow ... 80.jpg?c=2





I made this up for flushing the engine and raw water wash down. It attaches to the thru hull pick-up on the bottom of the boat. It also works for the marine air unit attached the same way. I have a small 120V pump and place it in a small kiddy pool ,slide it under the boat pour -50 propylene glycol in the pool, place a bucket near the discharge fitting on the side of the boat to catch the anti freeze, plug the pump in ,pour a small amount of pink in the strainer to prime the pump, put the lid on. I turn air unit on, when pink comes out of the side hull fitting, air unit off, winterize complete. I then move the pool under the engine/raw water wash down thru hull ( bottom of boat), attach the flushing devise to thru hull fitting grate, 6 gallons of -50 propylene glycol in pool, place a 5 gallon bucket under exhaust outlet at stern, turn pump on, take cover off the strainer fill with pink( takes about a gallon), install cover, start engine, when pink starts coming out of exhaust shut engine down. I put 3 more gallons in the pool turn raw water pump on and when pink comes out of hose that system is complete. I finish with starting engine again and run for approx 30 seconds to insure a good concentration of -50 propylene glycol is in the freshwater cooling system of the engine ( muffler holds the most) All sea water components are now winterized. Doing this by myself takes about an hour. That is set up , winterize and put everything away. No hand tools needed! Note: always insure there is adequate anti freeze in pool, don't let it run dry. I start out with ten gallons of antifreeze. This is enough to do raw water system and fresh water system. I by pass the hot water tank so no anti-freeze is used for tank. I try to catch as much antifreeze as I can after it is discharged so I'm not wasting it. I reuse it for the engine raw water system only.