Weird Pressure Issue

[JamieAngst]

Morning -

I have a weird water pressure issue going on in my house that I’m not sure how to address. I noticed it (I think) start after I replaced my water heater and expansion tank.

1. Replaced water heater and expansion tank. Set expansion tank to monitored pressure at my washer (~55ish)
2. Put the water pressure gauge on the outside hose overnight and it sat around 55-60 but the secondary red showed 80
3. Pipes bang throughout the day. Showers drip every now and then
4. My home has a regulator that sits after public water. Maybe this is faulty or needs to be adjusted?

So it appears the pressure is around 55 for most of the day and occasionally shoots to 80 for no obvious reason. What should I be checking?

Thanks!

 

[havasu]

It seems that your pressure reducing valve is/has failed. I'd start with replacing it.

 

[RS]

If the pressure jumps to 80 your regulator is not working. And maybe your expansion tank is not set up correctly, they should be precharged to somewhat below you minimum pressure.

 

[Twowaxhack]

The pressure at my home reads 75-90 psi

I don’t have any problems with that. Fluidmaster ballcocks and mostly Delta faucets. Type L copper inside with a pvc main that stops at the foundation. Slab foundation.
No water hammer arrestors

The pipe has s plastic insulator where it passes through any framing. I soldered every joint 22 yrs ago.

 

[JamieAngst]

If the pressure jumps to 80 your regulator is not working. And maybe your expansion tank is not set up correctly, they should be precharged to somewhat below you minimum pressure.

I was thinking it may be the expansion tank since it started after that was installed. I will triple check the pressure on that. Thanks

 

[Twowaxhack]

Turn the water off, bleed off the water pressure.

Now, check the expansion tank pressure