Thread: Water Heater That Almost Went BOOM

Gentlemen this is my first post. I am a plumbing contractor (Master Plumber) in Allentown,PA. I am 72 yrs of age still active in my trade but basically only do repair work any more.

The reason for this post to you inspectors, is backflow valves, static pressure on the main, thermal expansion tanks that work and relief valves that work. Also where a relief valve should discharge to (in my opinion).

The attached photos are from a water heater I removed about a month ago. The call came is as no hot water and water on the floor. I determined that the heater had to be replaced. It was a 52 gallon electric about 10 years old. I drained the heater, when empty I put a cutter on the hot side outlet and cut the copper. Wham! The pipe jumped when the cutter went through one side. I thought "what the hell made that jump like that?" So I cut the cold side, jumped again and was pushed so tight I could not move the pipe. I cut about 3 inches lower and had to twist out the 3" piece. The water heater damn near fell over. What I has was a roly-poly doll on my hands. I got it on a hand truck and got it out of the room. Now when a water heater is made the bottom curves up into the tank (concave shape) This heater on the bottom was bowed out (convex shape). The photos will show this. This was so close to blowing up, I don't know why it didn't. Now I knew had to check and find out what happened. First the static pressure was 90 PSI the local authority came in and put a Watts double check on the meter. There was no thermal expansion tank on job. The relief valve did not blow? Why! Upon examination of same it showed a lime build up above the seat washer so bad the the spring could not compress. The heater was in an office so it was not used for more than washing hands. However there was a shower in the bath and the owenr would go to the gym three days a week and the take a shower when she got to the office. During those showers probably the relief valve started to drip a bit. The drip was never noticed and the water evaporated. Reason the drain went behind the heater. The slow drip for a number of years caused the lime build up. Posted just to make the inspection trade aware of items to look for.

Thanks for listening.

PS On my web site there is a link to water heater explosions.

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Thanks Bill. Your experience and knowledge are appreciated. Don't be afraid to correct us when we get something wrong or make a dumb statement.

Thanks for sharing that with us. Feel free to share your experience with us as it makes us all better inspectors.

Thanks, Bill. You have to wonder how many more are like that, but daily use keeps them from building pressure?

I think you're saying the discharge tube should drip where it is readily visible?

Originally Posted by BILL PARR

Upon examination of same it showed a lime build up above the seat washer so bad the the spring could not compress....

Welcome to the board, and as others say, don't hesitate to comment on anything of interest!

BTW, did you happen to tale a picture of the build-up on the TPRV?