MK II water heater - revisited

[Stefanojo]

Hello brain trust. I know this topic has been addressed several times, but I haven't seen my particular issue mentioned. Looks like the temperature/pressure relief valve is stuck open. It's rather high up on the tank and it's been leaking now for three or four days, so I would think that the water level would be below the outlet. But there is a steady trickle of water from the hose into the bilge. I have water pressure turned off as well as the water heater. Secondly, have any of you replaced this valve before?

[Jim Hardesty]

Secondly, have any of you replaced this valve before?

Yes, I have replaced with one from local hardware on a previous boat.  It wasn't the correct one ie tripped at higher pressure, but it worked.  The boat had copper pipes, so I wasn't concerned with the pressure.  It unscrews, has a pipe thread.  You may be able to find the correct one, the information is on the valve.
Before you replace it try tripping the little lever on the valve a few times to flush the valve. That may fix it.
Jim

[waughoo]

It is likely causing a siphon which is why it is draining down without the pump turned on.  The valve is easy enough to replace.  I used one from a hardware store, but you should be able to find the Kumma or Whale part from a marine supplier if you are that dedicated to the cause.

[Noah]

Just a random comment story about that pressure relief valve. When I purchased my boat the marine survey "dictated" that I attach a length of hose from the valve into the bilge to direct any water that may be released from the valve straight down into the bilge. OK. Sure. Not a bad suggestion.

[waughoo]

Noah,

I added one to my replacement.  It keeps the plywood shelf from getting damaged from the expelled water.

[Ron Hill]

Steve : I replaced one and what I did was take the old one to a hardware store so I could get a new one THE SAME LENGTH!!  The pressure should be on the valve

What I've found on the boat or at home if you ever have the pressure relief valve open (whether from pressure or if you opened it) you might as well replace it - because crud/calcium from the tank gets in the valve gasket and it will always leak!!

A few thoughts

[Stefanojo]

Really appreciate the input. Thank you.

I like the idea of taking it with me to the hardware store to make sure it's the same length.

Thanks again!

[Steve McGill]

I took a pic of mine with ruler next to it so regardless of where I was I had what I needed. Good luck