Hot water heater leaking at relief valve

[drssg]

I have a 10 gallon electric hot water heater in my barn that is about 15 years old, and I recently noticed some hot water dribbling out of the pressure relief valve. My wife had recently washed her horse, and she said she used all the hot water in the process. I currently have the water and electric turned off to the heater, so I don't know whether the leaking would have been temporary.

So I have two questions that come to mind. First, could this be considered normal? The tank went from 10 gallons of cold water to 10 gallons of hot water, and I could see where that would cause expansion and some of the hot water would leak out.

Second, I noticed that there is no tube attached to the pressure relief valve, so the water was leaking onto the plywood that is supporting the water heater on its shelf. At a minimum, I would like to divert that water, so it doesn't eventually rot out the wood.

I would be OK with a small amount of water being diverted straight down to the side of the plywood. It would fall on the lid of a sump in that corner. There is also a sink near the corner.

I would appreciate advice on whether the leakage is normal, how best to divert any leakage, and anything else I am missing. I'm definitely not a plumber, and I'm open to calling one, but I also like to fix things myself when I can.

 

[Larry Caldwell]

Replace the relief valve. Once they pop, they will never seat again.

You should have an expansion tank somewhere in the water line to prevent expansion over-pressure.

You can use cheap PVC pipe for a relief. Discharge into a sump is a great idea. There should be a drip pan with a drain under the water heater for when it springs a leak, and it will leak, because there's no room above it to replace the sacrificial anode.

 

[grsthegreat]

I have a similar 10 gal wh in my tack room. I used a drip pan and piped that and the pressure relief over to an area where it would not drain into the tack room, yet let me see if it was leaking. My old one lasted about 15 years until it kept tripping circuit. Cheaper to replace than to repair.

 

[ponytug]

As others have commented, it all depends on whether you have an expansion tank plumbed into your water system. Everyone on a well does. If you have a check valve (or a back flow preventer) in the system and no expansion tank beyond it, it is a recipe for not good things.

The bad news is that as @Larry Caldwell mentioned, once the relief valves leak, you need a new one. Whether you need a new water heater is a different question. When you put the temperature/over pressure valve in, yes, I would plumb in an overflow line using piping rated for high temperature, whether you direct it to the sump or the sink I think is your call. However, I would bear in mind in the case of over temperature (thermostat failing on), you will have boiling water and steam exploding out. So a straight shot to the sump would be my choice. I would hate to be at the sink if boiling water started coming out the pipe.

If you replace the tank, I would also put in a drip pan. They make electronic anodes that don't need to be replaced, but if you are getting fifteen plus years out of your water heater, I am not sure that it is worth it.

All the best,

Peter

 

[BeezFun]

Replace the relief valve. Once they pop, they will never seat again.

You can use cheap PVC pipe for a relief. Discharge into a sump is a great idea. There should be a drip pan with a drain under the water heater for when it springs a leak, and it will leak, because there's no room above it to replace the sacrificial anode.

I agree on the relief valve, replace it.
PVC isn't supposed to be used for the relief extension, it's not rated for the heat. But CPVC will work if you don't want to go copper.

 

[BeezFun]

They make electronic anodes that don't need to be replaced, but if you are getting fifteen plus years out of your water heater, I am not sure that it is worth it.

I started putting electronic anodes on mine about 20 years ago because our water was killing off anodes like flies. Last time I bought a new tank I laid it down in the driveway and took the anode out in a place where I could easily hold the tank and put a big wrench on the anode. It can be almost impossible to get those things out once they're 10 or 15 years old. The electronic one is nice, It's like a plumb bob hanging from a spring.

 

[Deere Dude]

A few weeks ago I saw water on the garage floor and traced it to a HW relief valve. I flushed it a few times and then put a pan under to see if it would leak again. It did continue to leak a little bit. I have a CPVC pipe directing it to 6" above the floor.

I went to Lowes and got a brand new one and put the CPVC pipe back on and put a pan under it again to keep track of any leaks. Over a few weeks it leaked a quart or two again. Don't understand why other than a bad new valve.

In your case OP I would change the valve and install a CPVC overflow pipe and direct to the floor or a sump. Easier than replacing the plywood base.

 

[Clint S]

Remember that is a Temp AND Pressure relief valve. So could be a bad t stat, that is overheating the water also.

 

[drssg]

Thank you for all the feedback. So I'm learning of a number of issues with this water heater and installation.

1. Pressure relief valve has gone bad.
2. No piping connected to the pressure relief valve.
3. There is no expansion tank near the heater.
4. No drip pan under the water heater for when it fails.

Are the expansion tanks a somewhat newer idea? The current water heater in my house has one, but I don't recall seeing one on any other water heater I've had prior to that. Would I be foolish to hold off on #3 and #4 until I replace the water heater?

I think I would be comfortable dealing with #1 and #2. #3 is beyond my comfort and experience to fix myself. If I fix #3 now, I'd be inclined to just hire a plumber and also replace the water heater. I'm rather undecided on how to proceed at this point.

 

[drssg]

I did test turning the water and electric back on, and the relief valve started dripping again fairly quickly. It then started to drip faster as the water heated up, so my initial hope that this might be a temporary issue was unfounded.

There is a pressure regulator and back flow preventer as part of the barn plumbing, but not an expansion tank.