how do you replace a pressure relief valve on a hot water heater? do you really need a plumber?

Question

the water spews out when left on for a long period. have to cut water supply off everyday.

Answer 1

These valves are cheap and there's only one problem replacing them -- sometimes they're hard to unscrew. You may need a long handled wrench with a cheater. Turn off the gas or electricity and cold water supply to the tank. You only need to drain enough water to get below the level of the valve. Don't drain a lot of water until you've broken the valve loose, so the weight of the water helps keep the heater from moving while you pull on the wrench.

Wrap some teflon tape on the threads of the new valve when you replace it.

Note: If you also replace the discharge tube, it must be made of a material that's rated for both high temperature and pressure. This includes most rigid wall copper, iron and, in most places, chlorinated polyvinylchloride (CPVC plastic not regular PVC) pipe. The pipe size must match the opening size of the TPR valve discharge (usually ¾ inch). It must terminate 6"-12" above the floor, and the end cannot be threaded or have a fitting which permits connecting a plug or cap.

Answer 2

You might not need to replace the valve. In fact, sounds like what you need to do is turn down the water heater a little to keep the pressure within limits.
In the case that you do need to replace it, make sure that the tank is cool ( been turned off for several hours or even a day ), so there will be no pressure, then take the old one off and put on the new one. Make sure that the new one is the same pressure rating as the old one. The valve is intended to "pop" before the tank exceeds it's pressure rating and bursts. A bursting tank even a small one can do unbelievable damage. Think of a small tornado inside your house.

Answer 3

I agree with Roamin. Check your thermostat first. It may be set too high or is defective. The fact that the valve doesn't pop until the heater has set idle for a long time tells me that the water is getting too hot. If setting it to a lower temp doesn't work I'd suggest a plumber, for safety's sake, to check it out. If your water heater is old, say over 10-15 years, I suggest just getting a new one rather than do repairs. They're not all that expensive.

Answer 4

Simply shut the water off, use a large pair of pliers or pipe wrench, unscrew the fitting. Before you put in a new one, wrap it with plumbers tape and just screw it on. Very cheap & easy project.

Answer 5

It maybe 2 problems 1-temprature set too high or you may need a thermal expansion tank. Do you have a backflow preventer on the main line ? if you do then you will need the thermal expnsion tank if not then check the thermostat setting is set to high should be set to 120 degrees normal setting.