Hot water heater, pressure relief valve

[Dean Abramson]

We have a Force 10 hot water heater. Apparently the brand name is now Kuuma: https://www.marinepartssource.com/6-gal ... sCEALw_wcB

There is a pressure relief valve in the end of it. I have always flipped up the lever on that valve (out straight, away from the heater body), to open it, to let air in when I am draining the heater. Yesterday I did that, but the valve did not feel the same, it did not have a distinct hard "sticking point" (making the lever a bit hard to get into the position) like it had before. It was kind of a limp noodle in comparison, but it would stay in the flipped-out, open position.

But, to my surprise, when I opened the drain tap at the bottom of the heater, nothing would flow out. That tells me that the valve has failed, and it has failed in the closed position. I am going to try to find a new valve and install it. (It seems to me it ought to be designed to fail in the open position, but what do I know?)

But it's a total b!tc# to get at, and plumbing is not my long suit. So here's the question: What if I do nothing?

We do not use AC power on our boat; the cord was cut by me many moons ago. The water is only heated by the engine coolant when we are motoring. The engine runs reliably in the 165 degree range. So, there is no way I can boil water in the heater. Right? So, do I need a pressure relief valve? We have found a way to drain the tank without having a functioning valve.

Then there's this: yesterday we drained the sucker by running the freshwater pump til the heater was dry. Now, since the heater hold six gallons, that means we chased that water with a lot of air. I aim guessing we ran the pump for around 5 -10 minutes. Which begs the question: are we damaging the pump by doing that? Most of that time it was running dry, pumping air. Frankly I was amazed it worked a all; but we did get 6 gallons out of the heater.

Obviously, if I can change the valve, I will. But if that's too hard, can I a) live without the valve, and b) run my pump dry for maybe as much as ten minutes, once a year?

???

[Carl Thunberg]

Among my various careers, I used to be a plumber. I owe you and Marvo a visit anyway. Or you, Rich, and I scratch our heads over a couple beers and figure it out. The fix is pretty simple, so it would be more about beer. You cannot service them. When they go, you replace them. You really don't want a temperature and pressure relief valve to fail in the open position.

[Dean Abramson]

Hey Carl!

Come visit any time. The boat should be back here in a about a week; I'll let you know when it arrives.

Just FYI, though, ours is stuck (apparently) in the closed position.

Definitely, come see us. We'll play with the heater, and we will consume the beer.

Bring the missus, if you will. We'll put you guys up in the guest room.

[bottomscraper]

If this is the right one and you can get the old one out it just might be the least expensive thing you can buy for a boat

https://search.defender.com/?expression=400693&x=7&y=7