Surge in Water Pressure

[deporter]

About 6 months ago I replaced a shower cartridge and ever since then I've noticed a change in water pressure throughout the house. Anytime we turn on a faucet there is an initial surge in pressure (no more than 3 seconds) and then it drops back down. I really notice it when our washer is on. You can hear the water surge and pipes shake in the kitchen even with the washer upstairs.

When I replaced the cartridge I ended up closing the water line from the street. I couldn't find a shutoff valve anywhere in the house. I looked under all the sinks, in the garage, closets, etc. and couldn't find it. There were two valve handles coming from the water main on the street that I closed and opened them once the project was done. There is also a pressure relief valve there.

Not sure if this is related or not, but our water heater had been dripping a lot of condensation out of the relief valve. I had a gallon bucket sitting underneath the pipe that would easily fill up in two days. We decided to replace it to see if it would help (it had just passed the 15 year mark). The new water heater still drips, but not nearly as much as the last one.

The water dispenser on our fridge also started dripping after the shower repair. Not sure if it's doing it because of the pressure or not, but something to take into consideration.

Lastly, I did buy a pressure gauge and hooked it up to an outdoor spigot. The pressure was at 60 initially and then dropped down between 50 and 55 after about 15 seconds. I left it on over night and checked it before using any water and it read 76.

Any thoughts?

 

[Caduceus]

Sounds like a thermal expansion issue that may be unrelated to the cartridge replacement. Do you have a pressure regulator and/or back flow device on your water service? What is the temperature setting on your hot water tank?

 

[deporter]

I talked to my father-in-law who is a plumber about the issue. I don't normally talk to him about this stuff because I've seen some of the shotty plumbing work he's done. He thought it might be a thermal expansion issue as well. He bought us an expansion tank through his wholesaler, but I haven't had a chance to hook it up yet. I thought about asking him to do it, but I don't want to fix the leaks once he's done. I'll let you know if that resolves the issue.

In response to your question, there is a pressure regulator on the line by the street. I'm not sure of the exact temperature, but we generally keep it low with a toddler in the house. The control knob is set just above the medium setting on our Bradford White tank.

 

[johnjh2o]

I think you may be a little confused. A pressure regulator (or PRV) has nothing to do with water temperature. That is controlled by the water heater. It may be as simple as you didn't get the valves at the street turned on all the way or possibly one is broken. You say there were two valves, that sounds like a back flow device. If you have a PRV or back flow device then as caduceus said you need a thermal expansion tank.

John

 

[desertwater]

i believe is what your seeing for a short second is what used to be your normal water pressure.... actually is what you are seing is a loss of volume. i gurantee you have not lost pressure. make sure your valves are on correctly. what type are they? a picture would be great. dont make it complicated. all you did was replace a cartridge. the problem is where you shut the water off at.

 

[desertwater]

a half closed valve well also cause your water hammer issue. as far as thermal expansion, any body with a water heater and some sort of backflow device anywhere in the system has that. not a huge deal unless your water pressure is already really high such as 85psi.

 

[LiQuId]

water is most dense at 4', it expands at temperatures greated than this ( 1500 times when it turns to steam at 212 ) and also at temperatures lesser than this ( expanding 11% its volume when it freezes ) . your incoming pressure does nothing to effect the volume, you need an expansion tank.

I dont mean to sound insulting to you desertwater, I just believe you're overlooking the complaint of things "dripping", even on a new HWT which makes the problem expansion.

 

[deporter]

Sorry, John. I should've separated those two statements about the PRV and the water temperature. Another person (Caduceus) asked questions about both of those things and I put them together. When the sun comes up a bit more I'll go take a picture of the valves at the street and you guys can see if I did something wrong.

One other question, is it possible to hear pipes expanding or contracting due to expansion? The water lines and drain pipe for our master bedroom shower run up one of the walls in our family room. Every now and then I can hear sounds coming from the wall which sound a lot like little "popping" noises. At first I thought it might be mice, but after spending some time in the crawl space I found no evidence of rodents, ants, termites, etc. What I did see were the drain pipes and water lines in that exact spot.

 

[deporter]

The two blue valves are what I turned when I replaced the cartridge. They were in a vertical position when they were closed.The valve on the left is closest to the street. Let me know if you need to see anything else. I'll be putting the expansion tank in on Wednesday and will let you know if that works.

 

[phishfood]

That is definitely a backflow prevention valve in the last picture.

And that appears to be a pressure reducing valve directly attached to the meter. If the pressure reducing valve is allowing the pressure to creep upward, this could cause your problems. But I would tend to bet on the thermal expansion being the problem.

 

[deporter]

The new expansion tank seems to have solved the problem. I don't notice any changes in water pressure and the water heater has stopped dripping water out of the relief valve. Thanks for all the helpful suggestions.

 

[LiQuId]

glad to help