[trix2]

About every 5 minutes my pipes pulsate for about 30 sec. I have just done a renovation and added new plumming fixtures.
The city has flushed their pipes.
Do not have a sprinkler systen or surge tank. I did turn off the water to the hot water tank and the surging stopped. Both my plummer and the city don't have a solution. Please help - its driving me crazy.

[hkstroud]

How long since you drained and flushed you water heater?

[trix2]

The water heater is lesss then 2 years old and I have never drained or flushed it. During the remodeling the plummer connected new inlet and outlet PVC(?) pipes.

[hkstroud]

Did the plumber install any kind of device on the output line of the water heater? I know of one municipality that requires a pressure regulator on the water heater outlet pipe if CPVC pipes are used.

[trix2]

Nothing was installed on the output line. The only thing different is that he put a flex line on the output to connect to the CPVC.
I'm draining and flushing the water heater and will post the results.
As far as I can determine there is no pressure reducer on the main line.

[hkstroud]

Was any kind of hot water recirculating pump installed?

[trix2]

Thanks for the replies.
No recirulationg pump.
Finished draining and flushing the water heater. Pretty clean except for some stuff that looked like sawdust? Still has the same problem.
When I turned on the faucet closest to the heater to vent the air, it vented for about 5-8 minutes and now no water from the open faucet.

[hkstroud]

No water, hot or cold or both, single leaver or two handle faucet? Remove aerator on spout. Any water?

[trix2]

It's a two handle faucet but only the hot side was effected. Cleaned the aerator and feed line, both had grit in them, but still some grit in the shut off valve. Hot is still very slow but will have to shut off the main valve to clean the sink shutoff valve.
Biggest problem is that I still have the pulsating pipes although I think it is a little less after draining and flushing.

[hkstroud]

I have the impression that the pulsating occurs even when no water is being used. Am I correct or is it only when hot water is being used?

[trix2]

You are correct, the pulsating occurs with no water being used, about every 10 minutes for about 10 sec.

[hkstroud]

If you had no recirculating pump installed under the cabinet or near the end of the line of you renovation, you must have something not plumbing related rubbing or vibrating a pipe. Sure sounds like a recirculation pump.

[trix2]

Thanks for your help.
Will start where the water comes into the house and try to find any interference or plumbing issues.
If I find an answer I'll post results so others won't have to go through all this trouble.

[speedball1]

Would this be a gas or electric heater?

[trix2]

It is an electric water heater

[speedball1]

This may seem silly, but humor me. The next time the pipes start to shimmy go out to the water heater and place your hand near the hot water outlet nipple. More vibration there? Now try the cold side. The way I track down a noise problem is to track it back to where the vibration's the greatest. That's the source and once you know that you got it whipped. Cheers, Tom

[Handyman2007]

When you flushed the water heater and refilled it, did you open ALL of the hot water faucets in the place when it was filling? If you didn't , there is more than likely some air still trapped in the water heater and the pulsating is from a heat expansion taking place. I always open all the hot faucets and run the water into the heater and make sure there is absolutely NO AIR coming out before closing them.

[speedball1]

Handyman, I don't believe it's air in the lines that's causing the pipes to pulsate. If it were air simply opening any hot water faucet would bleed the system down. But I like the way you went about analyzing it. Heat expansion in a water heater expands one mof two ways. It expands back down the cold water inlet or it expands into a expansion tank. It don't run around knocking pipes. But still, good reasoning on your part.
TRIX; Herald may be on to something. Do you have a recirculation pump installed? Regards, Tom

[trix2]

Tom- The hot side, at the nipple does not vibrate however the cold side does. This may not be a fair comparison because the cold side has about a 1 foot long flex pipe before it connects to the CPVC

Handyman 2007 - I drained and flushed again and refilled with all the hot water faucets open. Closed the farthest away faucets first. It helped a little but still vibrating with the circuit braker still off, cold water.

[trix2]

Do not have a recirculation pump installed