why is my hot water heater pop off valve occ. releasing h20.It is not the valve, replaced twice.?

Question

I have replaced the valve twice in the last couple of weeks and the last valve is one to with stand more pressure and it still releases water.

Answer 1

I AM A LICENSED PLUMBER AND THIS IS USUALLY CAUSED BECAUSE THE HEATER IS HEATING THE WATER UP SO FAST IT BUILDS UP TO MUCH PRESSURE ESPECIALLY IF IT IS A NEEW TANK OR NEW FAST RECOVERY ELEMENTS, AS IT HEATS THE PRESSURE CANNOT GO BACK INTO THE LINEES BECAUSE OF A CHECK VALVE THAT IS INSTALLED IN YOUR METER, YOU USUALLY HAVE TO BUY A SUSPENSIION TANK AT YOUR HARDWARE STORE AND HAVE IT INSTALLED IN YOUR WATER LINE ABOVE HEATER TO RELEASE THE PRESSURE, GOOD LUCK.

Answer 2

Your pressure relief may leak for four reasons; the water pressure in your building is too high, the temperature of the water is too hot, you have a pressure regulator that is stopping the water from bouncing back when you turn fixtures off, or you need an expansion tank.
Check your water pressure by installing a water pressure test guage on a garden hose faucet. The pressure should not be more than 80 pounds. If is is over 80 pounds you need a regulator or the one you have is broke.
Pressure regulators also cause problems. When a water faucet is turned off the water bounces backwards through the pipe and water heater. The water bounces backward all the way past the pipes coming into the home. The pressure regulator allows the water to travel in only one direction. When the water bounces back it will literally cause the water heater to expand a tiny amount like a balloon. This creates an immense pressure that causes the pressure relief valve to open.
When you have a pressure valve or your home has a water well and pump you need an expansion tank. Like the pressure regulator, a water well pump will not allow the water to bounce backward. Also, when the hot water is heated it expands. When the water cannot go backwards in the pipe, the water will expand and open the pressure relief valve.
Check the water temperature with a temperature guage. I'm not positive about the correct temperature. I think 120 degrees is the temperature needed for dishwashers and probably 140 is tha max.
The last reason a PR valve will leak is corrosion. This can occur in as little as a few months with bad conditions.

Answer 3

That's a good question.

The first thing to look at would be the temperature setting.
Is it set real high? If that is so, turn it down some.

Do you have your own well? If so your pump pressure may be to high. With city water the pressure as a rule doesn't get to high.

Is your heater older? If so the tank may have become filled with mineral deposits on the bottom. This means that it will take it longer to heat up because of the junk on the bottom of the tank.
This stuff will get very hot & heat the water even after the burner stops. This extra heat can cause the water temperature to get to high & set off the relief valve.

If you can run some hot water to make the burner go on, then wait
to see if the relief valve goes off before the burner shuts off.
When the burner just stops & you can hear popping noises.
That is a clue that mineral deposits have built up.
If the valve goes off at this time you may buy some time while you shop for a new heater by turning the temperature down.

It isn't a good idea to put a higher rated relief valve on the heater.

All in all it well could be time for a new heater.

Answer 4

Stephen, Man, I wish you'd quit trying to answer questions dealing with things you know nothing about. I don't know what century you grew up in, but as far back as I can remember, and that's a ways, there's never been a residential water heater, gas or electric, that has had a float of any kind, inside of it. They are made to be filled clear up to the very top, until the water contacts the inside of the metal of the tank. They cannot overfill, and there's no float system to keep that from happening. I'd be really interested to know where you get your information about water heaters, because you're reading the wrong books. Nickels, as to your problem with the overflow valve, I'd be curious to know just how much water is coming from the overflow valve. Because, at this point, if it's a small enough amount to catch in a small can or pail of some sort, which you could empty at some interval or maybe it would just evaporate, I'd go that route instead of jacking around with all the plumbing and expansion tanks and all. I've installed over 500 water heaters, gas and electric, 80 gal. down to 3 gal. and all sizes inbetween, and I've never installed an expansion tank on any of them, and they're all still in service. Now, it would seem to me that if they were that important and necessary, that somewhere in the last 35 years and over 500 installations, that one of them would have gone bad because of that. So far, nada. I really don't know why the valves are going bad so quickly, other than the possibility that you have so much corrosive material in your water that it's eating out the gaskets quickly. But that would probably mean that the water would be causing you serious health problems as well. So if you're in even moderate good health, that's probably not it. Malcolm, I'm going to give you yours, (the part about the cold side of the waterheater installation being at a lower pressure than the heated side), only because I don't know if all water heaters now have a check valve incorporated into the entrance fitting of each unit which would stop back flow. That would be the only way your theory could possibly come to fruition. In units without the check valve, the pressure on either line would be the same, as regardless of hot or cold, they are both connected to the same system.

Answer 5

well, Ive had this happen a few times myself, and it is usually the valve is working correctly...if it didnt your heater would blow up!
For me, this has happened when the heater has gotten old, and neglected, and has build up inside the unit...and possibly if electric, only the top element is heating because of all the build up inside the tank,,,,and thus its trying to keep it hot, yet it gets too hot at the top while the thermostat still thinks it needs to get hotter..since thatis in a differant location on the tank... I simjply replace the tank...

Answer 6

heating water in a tank, is kinda like lighting a fuse on a bomb. Pressure is going to build until the heater shuts off or the valve pops. check the water temperature, at the drain. could be your heater thermostat is not working

Answer 7

Your tanks temperature controller may not be working properly, the water in your tank may be getting to warm and as a result the pressure relief valve is opening.

Answer 8

Your heater is full of Lime from hard water. Time to replace heater.

Answer 9

Make sure that the thremostat on the thing isnt malfunctioning and causing the burner to burn too long and overheating the tank

Answer 10

ether too hot or too much pressure or bad valve