Electric Hot Water Tank Pressure Release Valve Leaking, Why?
Our big brother( homeland security) has instructed the water company's to install anti back up valves in the water system to keep us safe from terrorists trying to back flow chemicals into the water system. I would check with water company and see if this has been recently done at your house meter.The problem is no where for the pressure to go when the water heats up. you will as all others will have to install a pressure expansion tank. If you find this not to be the case I would put a pressure gauge on one of your outside water valves and check the pressure.as the safety valve you are referring to will start to re leave some where around 70lbs and pop at 150 lbs. to keep from too much pressure build up. This can be caused by a tiny leak in the pressure regulator located in the incoming line. Hope this helps
did you recently increase the heat settings or change a thermostat? an increase in temperature can cause the pressure relief to go off a little...but usually only when the temperature gets up there (160-180oF) which is uncommon for electric. Unless the valves are shut off above the tank, the piping system should handle any pressure increase in an electric tank. Do you have a buffer tank on the hot water side? (usually only when you have hydronic heat) it could be saturated or pre-charged too high. If none of the above are probable, you may just have a bad pressure relief valve, I've changed one before, had to turn off the cold water and open up a cold tap to let all the pressure out of the system, bleed off the hot water until the pressure valve didn't spit out when I opened it, unscrewed the plastic downpipe from the valve(some have it, some don't) and remove/replace it with some teflon tape on the new one (20 bucks or so from the home depot)
Michael is correct here. The TP valve is an integral part of the unit and should be replaced if leaking, not merely flipped open and closed a few times and then forgotten. Besides the folks that are telling you to flip the lever open and closed are forgetting about shutting down the water supply first. If you don't shut off the water before doing this you'll have a fair amount of hot water splashing out on the floor, and if it's overheated water it could very well scald parts of your body. It's extremely dangerous to take the advice of strangers, on a forum such as this, about something like this that can cause you much trouble and grief. If you are a handy person it's a fairly simple repair to replace one of these. Just turn off the water supply valve to the tank, if it's separate, if not then shut down the house supply. Many people say you need to drain water off the tank so as not to get any on the floor, and if that's a big concern, then it's not a bad idea. However, once the water is cooled, with the supply shut down there's no more pressure and the tank is similar to a straw full of water with your finger over the top. The water won't flow out easily without an air supply above it. So, if you have your pipe wrench ready and can take the old valve loose, have the new one taped with teflon tape on the threads and ready, when you unscrew the final threads of the old one, stick the new one right into the hole and thread it in. You won't lose enough water to be concerned about and you'll have a new pressure relief valve in place. Be sure to tighten it down good. Refill whatever water has left and check for leaks.
They build up mineral deposits on the valve seat sometimes that will cause them to leak.Try lifting the lever to open it completely then flip it closed. That will sometimes clean the seat and stop the leaking. It might take two or three tries. If that doesn't stop the leak then you'll need to replace the valve.
The TP valve is the most crucial piece to your water heater and your safety, If all you do is open and close it in order to stop it from leaking, then you are taking a HUGE chance for it to fail. If that where to happen, you better pray you are not home because the TP valve is the ONLY devise a water heater has to prevent it from exploding. I am not trying to scare you, I just want to make you and anyone else aware of the extreme dangers, besides the temperature and pressure relief valve is very inexpensive and very easy to change.
