Gas HWH - water in drip pan
 

We have a 5 year old gas hot water heater and have been noticing water in the drip plan lately. I've seen it come out of the long narrow pipe attached to the pressure relief valve when the HWH was actively running. Never more than a pint of water, but , troubling nonetheless. We had the pressure relief valve replaced a couple of months ago when there was more water and it leaked out onto the garage floor.

In the HWH docs, it says you should test the pressure relief valve annually. Does anyone out there do that? Anybody else had these symptoms? Any clues? We would like to try the DIY approach before calling a plumber.

Thanks for any suggestions.

On the cold water side you will see a large object that looks like a can. It is an expansion tank. It has a diaphram inside. If the diaphram leaks water past and the can fills with water, it fails, (no room for expansion) your relief valve will seep and leak. The expansion tank should have half air, and half water. If you take your finger and tap on the side of the tank, half should sound hollow (air), half solid (water). If the whole thing sounds solid, full of water, you will need to replace it. You will see a schraider valve to add air to the new one. You can use a hand pump. The recommended pressure is on the tank. They are not very expensive. Hope this takes care of your problem.:ho:

It may just be the pressure relief valve. Easy to put a new one in. You need a wrench and plumbers tape. Cost less than $10. Turn the heater down or off, take the relief valve out, go to Ace and buy new relief valve and install.

Since it's only been a couple of months since you had the PR valve replaced, I would call the plumber that installed it. Could be that you got a defective one. If not, the diagnosis could have been wrong to begin with, i.e. the expansion canister.

It's also possible the temperature thermostat is set too high for the amount of time/quantity it's used causing it to overheat too much and open the relief value often. That is too much water being released for normal operation.
I've rarely tested the valve and I've had many over the years and can't even remember having an overflow problem. I've only changed the valve when a new hot water is installed and came with one. I used to have rental houses also that I did all the servicing on. Maybe just lucky.
As Opus stated, nothing to replacing them unless they're soldered in place to the copper pipe. Home Depot and Lowes can show you how.

Thanks for all the tips.

Expansion tank thumped normally .... more hollow sound at top, more full at bottom.

Temperature is not set that high and we are not big consumers of hot water.

We tested the pressure relief valve yesterday and the drain. After sopping up the water, we'll see if any more leaks out of the long pipe. If so, may be time to call the plumber.

Check Temp & sediment
 

1 Does it happen over night? Does it happen every day? If it happens sometimes it may be excess water pressure. They fill the "water tower" over night and sometimes over pressurize. May need to install a pressure guage and check it about 5 am. Pressure should be be 50-70 psi. 2 You may want to pull a sample of water from the drain on the heater. Check the temperature with a meat thermometer. Now lift the lever on the relief valve and take a water sample from the top of the tank. Check the temp. If the temp is above 170 degrees that may be your problem. ( need to make sure the heater is at normal operating temp. Flame is out). You may have a calcium build up on thermostat in the tank. 3. You may have a lot of sediment in the tank and the "dip tube" is pushing to it the top. Once the releif valve "lifts",sediment can get in the seal.

To close this one out....the problem was indeed the expansion tank. The bladder inside had broken and the tank was full of water rather than air.

We called Robert Isherwood ... took a couple of days to get him out, but, it was not an emergency. Seemed competent and had it fixed quickly. He said the chlorine in our water eats through these bladders in about 5 years. Newer tanks are good for more like 7 years. Since we had already replaced the pressure relief valve, he didn't mess with that. Normally, at the 5+ year mark he will replace both items at the same time.

Anyway, something to watch out for if your house is starting to get some years on it...

I had the same problem and thanks to this blog I took care of it myself. The tapping on the expansion tank made it obvious that the tank was full of water. Now that I put the new tank in it is only about half-filled with water as its supposed to be. The new one came pre-charged with 20 psi air and the label said that would be good for most applications so thats where I left it. Its really a quick, simple replacement. Thanks to all for the help.

We had the same problem when we bought our pre-own. I knew the pressure valve was just replaced, I also knew I turned the temp up because it takes so dang long to get hot water to come into the master bath. I turned the temp down, the leak stopped and no change in how long it takes to get water to the master.

Just to add here, if the tanks do need replacing every 5 years or so, perhaps it might be a good idea to add a 1/2" ball valve just before it, so future replacements can be more easily done. Just a thought.

Frank

i thinik its a great idea:agree:

I've got an Amtrol Pro Flo PT 5 expansion tank that's almost 8 yrs old. Have had the pressure relief valve leak into the pan which resulted in numerous pin holes from corrosion. Then the pan leaked onto the wooden base and started to warp the plywood base. I ended up using a hose to route the water out through the wall. I see now, the problem is probably the expansion tank.

I'd like to replace the expansion tank with the same brand. Looks like the Amtrol Extrol ST-5 is the direct replacement. Anyone know where I can pick one up locally? By the way, this tank has 3/4" NPT. same size ball shutoff for easy next time replacement?:bigbow: