Hot Water Tank Pressure Relief Valve What Size

[Bob & Sue]

We were out last week for a cruise after docking I opened up the engine hatch and noticed a couple drips of water coming out of the pressure relief valve on the hot water tank it's a 6 gallon tank.

I had to leave before getting a size or part number does anyone know what the specs are for it?

Can't find anything in the manual or online even called Sea Ray parts they didn't have a clue, want to replace it next week without having to make a couple trips to get a new one.

 

[Lazy Daze]

Bob, I don't know for sure but 1/2" NPT seems to ring a bell. BUT, if no one can 100% confirm, I would call Atwood Mobile. Atwood is the one that made it, so they would be the best ones to call. I suppose you could just google the part number from your manual, too.

Isn't your pressure relief valve plumbed to a black hose that goes to a thru-hull fitting? It is quite normal, though, for a pressure valve to drip a little - that's exactly what it is designed to do.

 

[Bob & Sue]

Thanks I was just looking at Atwoods site, the manual didn't have a manufacturer name. No mine just dumps onto the shelf into the bilge, I'd rather it went out a thru hull.

Maybe I'll just watch it for now before replacing.

 

[Lazy Daze]

I've googled them in the past by just using something like "Atwood" along with the part number from the book. Try that - you should get some results that way.

I agree - I would just keep an eye on it - it might simply just be doing it's job - especially after a long cruise/run.

It would be VERY easy to add a length of heater hose and a simple thru-hull fitting.

 

[saopm]

I just replaced mine with a 100xl. It is a common pressure relief valve for hot water heaters. You should be able to find it at Home Depot.

 

[Westie]

I got one in the past at Home Depot too. Just get one with the same pressure and temperature rating.

 

[Sublimetime]

If its standard like mentioned above then it will be 3/4 npt thread. And it could have a length of hose on the "out" side which leads down to the bottom of bilge or overboard. tis is 3/4 also.

 

[Bob & Sue]

Dennis,
Thanks all for your replies.
I found the correct one after several more searches with the SR part number & having a buddy of mine at the local SR dealer go out and measure one on the same tank as mine. It's a 1/2" npt with 150psi relief valve. He had one in the shop he's holding for me. I'm having the boat hauled out in a couple weeks for cleaning I'm going to have a thru hull added then.

ATWOOD FITS 6, 11, 20 GAL ATWOOD HOT WATER HEATERS 1/2" PIPE SIZE. Manufacturer: ATWOOD WATER HEATERS Product ID: ATW91604

http://www.atlanticmarinedepot.com/...p-1507.html?osCsid=iub99rj8kr52otqf3km2k42k90

http://www.atlanticmarinedepot.com/...ter-heater-93891-120v-gallon-ehm6-p-1509.html

http://www.amazon.com/Atwood-91604-...=2025&creative=165953&creativeASIN=B000N9PRKG

 

[hottoddie]

I would caution re: adding a thru hull for the relief valve. Under normal circumstances the valve will not drip. Without knowing the height of the valve in relation to the waterline it may not drain at all. I would replace the valve and leave it alone. You don't need another hole in the side of your boat.

 

[Lazy Daze]

Cool - good find, Bob!

Bob, while you have the old valve out, you might want to give the heater a really good flushing... get rid of any sediment that has been building up on the bottom of the tank.

I would caution re: adding a thru hull for the relief valve. Under normal circumstances the valve will not drip. Without knowing the height of the valve in relation to the waterline it may not drain at all. I would replace the valve and leave it alone. You don't need another hole in the side of your boat.

Toddie - it's very common (in fact, I was surprised to hear that Bill's boat did NOT already have it) for the Sea Rays of his size to have a hose for a relief valve that leads to a thru-hull. It really is a simple install and also quite safe to do so. Adding a hole is no big deal - it's done all the time - and this one is one of the easiest to do. It's probably and hour or two job, tops. Now, whether Bill wants to do it or not - totally up to him. But there really aren't any issues to be worried about... other than the typical ones when drilling holes and sealing them. Draining is not a concern - in fact, the thru-hull will end up being HIGHER than the relief valve. You just don't want any dips in the hose, but that is also easy to accomplish.

Are you thinking that the thru-hull is through the BOTTOM of the boat? It's not - it would be through the side of the boat.