Bidet spiking water pressure reading

[GrnsShop]

I have a Toto Neorest 700 that's always filled fast, after flushing. I have enjoyed the quick recovery, but sometimes it clanks the pipe as soon as it stuffs off. Lately, it seems like it's a little louder than before (could just be now I'm aware of this, because of a gauge). My gauge sometimes shows scary high readings and I finally traced it back to the upstairs toilet. When I saw 160 PSI, I had to investigate!

I have a well system, so incoming pressure is variable. Currently, it's set to peak at 70 PSI. I plan to reduce that to 65 with a PRV separating the irrigation side and house side.

I'd imagine reducing the pressure further might help. is this normal behavior? I believe I installed a water hammer arrestor near the source, back when I was getting things ready for the fancy commode. Also, the gauge is on a spigot in the garage. It's fed by the softened side, just like the bathroom.

side note: I did have an issue with the softeners T&P valve on a old water heater, which was helped but not eliminated by replacing with a new one. Added an expansion tank, thinking it would probably be a good idea anyways, if I'm adding a PRV. I know that's another topic, just trying to cover my bases.

Thanks

 

[GrnsShop]

I forgot to add that the actual pressure isn't hitting these crazy numbers. The high needle is being forced higher by the rapid pressure change. Actual pressure is where it should be. Tried to upload a short clip of it, but it looks like video isn't allowed.

 

[Sponsor]

 

[Terry]

Video on YouTube can be linked as "Media"

 

[Reach4]

Try adding a water hammer arrestor as close to the valve as practical. That may be at the stop valve.

 

[John Gayewski]

Sounds like the fill valve needs replaced. Your getting water hammer when it shuts off. You could try closing the stop partially, but it really depends on some other factors whether this will work or not. Hammer arrestor also should stop it.

 

[GrnsShop]

I've been dialing down the fill valve in increments. It seems to have helped the hammering and the change in fill rate doesn't suffer much. Not really sure what changed, but I suppose the house is starting to show some age.

 

[Reach4]

I've been dialing down the fill valve in increments. It seems to have helped the hammering and the change in fill rate doesn't suffer much. Not really sure what changed, but I suppose the house is starting to show some age.

Do you mean you are partially closing the stop valve at the wall?

 

[GrnsShop]

Do you mean you are partially closing the stop valve at the wall?

Yes, I closed it up about one turn (proprietary decorative design). It helps a bit with the hammer, but it's still persistent. I could dial it down to the point it eliminates it, but the recovery time would suffer. I do have a water hammer arrestor on the cold side to the tub, less than six feet away.

 

[Reach4]

Water hammer arresters are for things with quick-operating valves. They work best when as close to the fast-closing valve as practical.

 

[GrnsShop]

Water hammer arresters are for things with quick-operating valves. They work best when as close to the fast-closing valve as practical.

I'll try moving it closer. One question though... I ran across air chambers, something I didn't know existed previously. Are they similar and/or somehow better? I read they can take up lots of space, but that's not a concern where I'm working.

 

[Reach4]

The old plumbing had air chambers that were usually a foot tall or more. The problem is that air dissolves in water. If you have those, you may or may not be able to get air back in by draining the water from your pipes.

The newer water hammer arrestors have captive air behind a piston, so that air cannot dissolve into the water.

 

[Tuttles Revenge]

The Junction valve or Stop valve isn't just decorative. It has a fine mesh screen inside. You can actually use the screwdriver stop to shut off water flow and pull out the screen without shutting down and draining the whole house.

The water enters the top unit and is divided to flushing and to bidet functions. The bidet functions are operated at low pressure through a pressure reducing valve internally. The bowl flushing has a vacuum and motor operated soleniod valve to switch from flushing to bowl filling functions.

I've had 1 other neorest with a slight water hammer problem that a simple water hammer arrestor fixed.