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  Topic Review (Newest First)
07-25-2012 03:08 PM
Re: hot water from the boat engine

What size WH did you get? and just because the hoses are hot from the engine it doesn't mean the heatX is not air bound. It has to be "burped" In any case the time to heat varies.
07-25-2012 02:14 PM
Tim R.
Re: hot water from the boat engine

The closed coolant system and domestic water system need to be isolated. There should be no mixing of these two systems.

When Eric references the "fresh" water side, he is referring to the engine coolant. The over-pressure valve is likely the expansion tank cap.

You need to bleed the air from the closed coolant system at the highest point in the loop. If you WH is higher than your engine, then you need to bleed the air out there. Or there should be a coolant expansion tank above the heater into which the air should normally escape. You should not need to remove a hose to bleed the system.

It can take a long time for the coolant to heat your water. Make sure you are operating the engine under load and give it at least an hour to heat the water.

If you have air in this coolant loop, your engine is probably not cooling properly.
07-25-2012 01:31 PM
Re: hot water from the boat engine

Eric said: "i bled the system by opening the overpressure valve on the fresh water side and just let the engine circulate the water until the air was bled out of the ststem."
I'm having a problem bleeding my hot water tank to get my engine coolant to circulate through it to make it work. I'm thinking I have air in the engine coolant line and I need to bleed the system. I tried opening the lines going from the engine to the tank and from the tank back to the engine. I got coolant to flow from both lines at the W.H. but still they won't heat up at the water heater. I also tried opening the over pressure valve and letting water drain from it, but it didn't show any air in the water line so I shut it off. I also tried opening the hot water faucets (maybe not long enough) but they also didn't show any air coming out.
My question is "how can opening the fresh water pressure relief valve, or even the hot water faucets, affect the engine coolant line?" They are two different lines. I was told to open the coolant intake and exhaust lines until coolant came out without air, which I did, but that didn't work either. The heater was working well until I drained it and disconnected it from the engine for the winter (big mistake).
any help would be appreciated.
10-21-2003 01:30 PM
hot water from the boat engine

I was just at my boat and the hoses get very hot very quikly under power, mabe 7 minuts or so and thay are hot right up to the water heater. I think that mabe the force 10 heater just has a crapy heat exchanger and it takes forever. I ran under hevy power for around 15 minuts and there was no real diferance in water tempature. any outher force 10 persons out there.
10-21-2003 11:14 AM
hot water from the boat engine

It takes me 45 minutes or so to get hot water if I''m running the engine just to make hot water. (Rarely) Quicker when I''m motoring somewhere. I bled the system by installing a valve in the coolant loop up at the heater (highest point). Then when I change coolant I can bleed the air from the system.

Best of luck
10-20-2003 06:53 PM
hot water from the boat engine

i bled the system by opening the overpressure valve on the fresh water side and just let the engine circulate the water until the air was bled out of the ststem. if your tang is highte than the engine you might have to add a bleeed valve to the coil side of the heater.
my engine takes about 30 minutes to heat 12 gallons of water to 180 degrees.
fair winds,
10-20-2003 04:15 PM
hot water from the boat engine

so how long dose it take for your water to get hot. and how did you bleed the system.
10-20-2003 08:14 AM
hot water from the boat engine

Had a similar problem on my boat. You may have an "air lock" if the heater is higher than the engine. I bled the air out of mine and this seemed to do do the trick. FYI - Check the hose temp at the hot water heater - mine was hot too where each end connected to the engines coolant system but the hoses were cooler by the heater.

Good luck
10-20-2003 05:54 AM
hot water from the boat engine

In my experience 1.5 hours is way too long and by then the water should be scaldingly hot. You may have some sort of problem with the plumbing and/or engine.
10-20-2003 12:53 AM
hot water from the boat engine

My Yamar 2GMF takes < 1/2 Hr to heat 5 Gal. HWT.
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