Problem with hot water heater after new meter installed

[bainboy76]

The water company installed a new meter a few weeks back. After they turned the water back on, I noticed the water pressure dropped. About a week after that, the hot water heater T/P valve emptied out about a cup or so of water after I had ran a tub of hot water. My hot water heater is located in my garage, I noticed the water on the concrete floor. A guy I work with told me they may have got trash in the line and it may have stopped up the reducer valve. I removed the reducer and took it apart and it was clogged up pretty bad. I cleaned it out real good and reinstalled it. Good news is that fixed the pressure, but the water heater still continued to empty out about a cup of water after either a long shower or tub of water was ran. I thought I'd start simple and replace the T/P valve. That didn't fix it. I tried turning the thermostat down from 120 to about 110. That seemed to help a little, but the T/P valve still opens up after a long shower or tub of water is ran.

One thing I have noticed is that after a few minutes of using some hot water, the pressure increases for a brief second then returns to normal when the water is turned back on from a faucet. I hope someone can help me out here. Thanks in advance.

[bainboy76]

Forgot to mention, its an electric hot water heater. Only 2 years old.

[bainboy76]

Only thing I can think of is that either the new meter has a check valve or they installed a check valve and I need an expansion tank. Could be wrong though. Never had a problem until they did the meter replacement.

[LiQuId]

is a good theory, a expansion tank should solve the problem. but why you would experience this problem after the meter replacement is beyond me, unless like you asay they installed a check.. have they done work on the main line ?? what was the reason for new meters.. i ask because it would seem that the pressure in the line is either greater now ( they did line work ) or, maybe they did in fact install a meter to isolate dwellings from the city main.. like a double detector check, in which case an expansion tank would help

[phishfood]

It certainly sounds as though they installed some type of check valve with the new meter.

[bainboy76]

They replaced the neighbors meter too, a few days before they replaced mine. When they did their meter, they dug up an area that went across the entire street. Might have replaced part of the main line then, but I never experienced a problem until they did my meter.

[bainboy76]

What size expansion tank do you recommend? My hot water heater is a dual element 40 gallon unit and water pressure is set at 40 psi.

[bainboy76]

I just talked to my plumber over the phone and told him the problem because I didn't want to tackle the expansion tank myself. He recommended replacing the reducer valve. He said every time he has tried cleaning them out, they never work right afterwards. I just went and bought a new one (Watts brand) and it has a thermal expansion valve made inside of it. I didn't know they had that. I bet that's what's wrong with my old one, the expansion valve is stopped up. I'm going to replace the reducer within the next couple days. I'll give a follow-up on the results.

[bainboy76]

Replaced the reducer valve yesterday, but wanted to wait until today to post. Everything is back to normal now. No more T/P valve discharging and water pressure is great. Glad to finally fix the problem.

[bainboy76]

Well, guess I spoke too soon. The T/P valve started opening again after using hot water. All I know to do is install an expansion tank.