Rheem Electric Water Heater - Relief Valve Replacement?

CMayo · Feb 25, 2022

I have a 40-gal Rheem electric water heater in my mobile home and I think I figured out that the relief valve is leaking about 10 gal/hr. Luckily, the discharge pipe runs to the outside so there's no water damage that I can see. I shut off the water inlet and the leak stopped. Opened the relief valve and turned the water back on, and it was gushing out the discharge port at full blast. I closed the relief valve and the leak returned to normal, and that's all the troubleshooting I could figure out to do.

I'm running the heater at about 80% of its max temperature; would that have damaged the relief valve?

Anyway, my big question is whether I should tackle replacing that valve myself. I'm not especially handy but I can turn a wrench and glue PVC (though it looks like that may be a threaded connection). Should that valve just screw out and the new one screws back in? Would Home Depot have the right valve for my unit?

Any comments would be really helpful!

Twowaxhack · Feb 25, 2022

I believe this one is it. Take the old one to the store with you.....

Turn water off, turn power off , bleed presssure off and unscrew counterclockwise.

Be careful installing the new one, if you squeeze the outlet it will deform and you won’t be able to screw an adapter into it.

Get a plug to temporarily screw into the outlet while you screw the valve into the tank. Don’t turn power back on until you take the plug out.
https://www.homedepot.com/p/Rheem-P...Y2xE7m9wsT4XbilaeXIaAlkrEALw_wcB&gclsrc=aw.ds

CMayo · Feb 25, 2022

Twowaxhack said:
I believe this one is it. Take the old one to the store with you.....

Turn water off, turn power off , bleed presssure off and unscrew counterclockwise.

Be careful installing the new one, if you squeeze the outlet it will deform and you won’t be able to screw an adapter into it.

Get a plug to temporarily screw into the outlet while you screw the valve into the tank. Don’t turn power back on until you take the plug out.
https://www.homedepot.com/p/Rheem-P...Y2xE7m9wsT4XbilaeXIaAlkrEALw_wcB&gclsrc=aw.ds

That is super helpful, thank you very much! I'll do exactly as you suggest!!

CMayo · Feb 26, 2022

Twowaxhack said:
I believe this one is it. Take the old one to the store with you.....

Turn water off, turn power off , bleed presssure off and unscrew counterclockwise.

Be careful installing the new one, if you squeeze the outlet it will deform and you won’t be able to screw an adapter into it.

Get a plug to temporarily screw into the outlet while you screw the valve into the tank. Don’t turn power back on until you take the plug out.
https://www.homedepot.com/p/Rheem-P...Y2xE7m9wsT4XbilaeXIaAlkrEALw_wcB&gclsrc=aw.ds

Just a quick follow-up to close out the thread... the repair went perfectly, thanks again for your help! The relief valve's discharge piping turned out to be CPVC which is sized differently enough from schedule 40 that I spent several very confused minutes in front of Home Depot's selection of PVC fittings trying to figure out why nothing matched my existing fittings, but I finally called for help and found the right parts, including some Oatey cement that was rated for CPVC.

So job's done, water's back on and heating, and no leaks! Yay!

Twowaxhack · Feb 27, 2022

Charles Mayo said:
Just a quick follow-up to close out the thread... the repair went perfectly, thanks again for your help! The relief valve's discharge piping turned out to be CPVC which is sized differently enough from schedule 40 that I spent several very confused minutes in front of Home Depot's selection of PVC fittings trying to figure out why nothing matched my existing fittings, but I finally called for help and found the right parts, including some Oatey cement that was rated for CPVC.

So job's done, water's back on and heating, and no leaks! Yay!

View attachment 33982

Check your water pressure and keep an eye on the water temp. If the temp creeps up higher than the thermostat setting you may have other problems.

You have well water with a bladder tank ?

CMayo · Feb 28, 2022

Twowaxhack said:
Check your water pressure and keep an eye on the water temp. If the temp creeps up higher than the thermostat setting you may have other problems.

You have well water with a bladder tank ?

Thanks for that. I'm on county water so there's no well involved. I don't have a water pressure gauge and don't know what I'd be looking for anyway, but my temp's set to roughly 145°f on the heater with the hot water tap registering ~135 on my instant-read kitchen thermometer.