winterize hot water heater?

[saltypat]

I have a small hot water heater on a 1984 sailboat. I do not know how to winterize it. I see the hoses which probably pass the water to the engine for heating. I see what is probably the hose which am guessing adds water to the hot water heater. i see a hose which has two components (I am guessing this takes out water, one to the galley and one to the sink in the head). Then I see a spigot-like appendage on the hot water heater(doesn't appear to be at the bottom of the heater).

I was considering winterizing my head and water system myself, but I don't know what to do about this approx. 5 GAL water heater. There was not information left on the boat and the water heater itself had no instructions on it.......

Any ideas out there how to treat this unit? Advice much appreciated.

Thanks, SaltyPat

[sailingfool]

You want to somehow route the fresh water supply around the tank so you don't need to fill the tank with antifreeze, and then drain the tank.

On my tank setup, there are two valves, one on the house water in hose and one on the house water out hose. Closing both these valves shunts the house water into a bypass hose so there is no house water going into the hot water tank. If you don't have a shunt like this, you can disconnect both hoses from the tank, and connect themn together for the same result. There should be a drain spigot. Open the spigot to empty all house water out of the tank. Close the spigot when empty. You are done.

When commissioning the boat, open both valves or re-attach the hoses.

[TrueBlue]

Our current boat has a tankless, on demand propane water heater. But, I remember all too clearly, having the need to winterize a water heater like this for many years with past boats.

Sailingfool's explanation was very concise and spot-on. You may find however, that your in and out hoses lack the cocks his convenient system has and will need to connect the two hose ends after draining the tank.

My hoses had NPT threaded female fittings that conected to the tank's male threaded nipples. What I used was a 10" length (your length may vary ) of bronze pipe, threaded at each end, to connect the two hose ends. Use teflon pipe thread tape to seal all connections.

This enabled pressurizing the system after draining, so a couple gallons of non-toxic pink anti-freeze could be pumped through. Be sure to closeguard those tiny bronze drain plugs - they are easily lost to the bilge's black hole . . . speaking from experience.

BTW, It's amazing how many boaters make the mistake of referring to their water heater as a "hot water heater".

[BarryL]

Hello,

Water heaters are pretty simple. There are two input lines and two output lines. One set of lines is the 'domestic' water, which means it comes in from your fresh water tank and goes out to the hot water lines (galley, head, etc.) The other lines are for engine supplied hot water. The water comes from the engine, goes through the water heater (where is goes through a heat exchanger, heating the domestic water) and out.

The valve you see is a pressure relief valve. As the water in the tank heats up it expands. If it gets too hot and expands to much the pressure relief valve opens and the water flows out instead of blowing up the tank.

The other posters have described the preferred method of winterizing the tank - you really want a bypass line for the domestic water, and a drain on the tank. However, on many boats this has not been done, and is difficult to do for all the obvious reasons that nothing on boat is easy to do.

My last boat had the hoses to the water heater basically glued on with globs of sealant. There was no way to reach the drain. I had to use 5 gallons of marine / rv antifreeze to winterize the water heater. Just keep adding the antifreeze until you see it come out the hot water taps in the galley and head. In the spring you will need to run a lot of water through the hot water tank to get the antifreeze out, but it's not difficult.

good luck,
Barry

[peterbelsky]

Water heaters are pretty simple. There are two input lines and two output lines. One set of lines is the 'domestic' water, which means it comes in from your fresh water tank and goes out to the hot water lines (galley, head, etc.) The other lines are for engine supplied hot water. The water comes from the engine, goes through the water heater (where is goes through a heat exchanger, heating the domestic water) and out.

Regarding the 2nd set of lines. Did you mean: the water goes from the "water heater" to the "engine heat exchanger" back to the water heater? I assume when you drain the water heater, you are also draining the water out or the engine heat exhanger.

yes?

[CapnHand]

Peter, The water circuit that cools the engine is typically laid up with the same pink antifreeze. Some others state success by draining the engine cooling water for winter. See here for a recent discussion.

Barry, If there is no apparent drain and the hoses can't be easily removed, the domestic lines can be cut to install a bypass and drain. This is what I did on mine in that situation. Please don't ask how long it took or how much it cost. It's an investment OK!!!!

[dave6330]

We've always used the pink antifreeze - ran the electric water pump with the taps open until all lines (hot and cold) were spitting air,put about four gallons of the pink stuff into both water tanks, then turn the pump back on, run the taps until you get pink stuff flowing and shut her down. No problems. The only drawback we've encountered was the multiple flushings of the system after breakup with fresh water, but that's not a bad thing, after all.