[dbld58]

No, some places like Lowe’s sell an air pressure regulator, labeled as pressure regulator, that is not actually a pressure regulator. It is an adjustable valve. Meaning that when flow is occurring, a restriction in the valve will actually lower the pressure, but in a static situation with no flow, the pressure will equalize. Sorry for soap boxing, but every time I see that device, I think about the problems it is going to cause for the buyer unless they truly understand what it is.

The technical challenge when using a restriction valve as a regulator is that the pressure drop will depend upon the incoming water pressure AND the flow rate. Impossible to set correctly in the “flushing potty” scenario.

It “sounds” like you have such a device, a restricting valve. A true pressure regulator will not migrate like that unless the regulator is bad. However, if you do have a true regulator, you can get sediment in the inner workings which will jam the regulator open and cause what you are observing.

Can you post a pic of the regulator that you installed?

If this is the case, and you install a regulator, it will be tempting to use the smallest one possible to hide inside the potty. Make sure that the regulator is rated to handle the flow rate that you want. If it’s too big to install in the potty, then place it after the shutoff valve for the potty in the water bay. Plenty of room to hide it there.

Here is the one that I could see migrating to equalize with the water system pressure instead of maintaining its lower setting:

https://smile.amazon.com/gp/product/B085...UTF8&psc=1

Here is what I installed yesterday:

https://smile.amazon.com/dp/B09BDFFC5R?p...ct_details

Both both, the toilet works perfectly right after I turn the water back on, but not after several hours pass by.

What really has me baffled is how this toilet worked in the first place, and how does the rear toilet work without having the same problem.  I am thinking I'll never know the answer, I just want it all to work so I can move on...

If anyone knows of a REAL water pressure regulator, could you please share? I am putting on a pressure gauge this afternoon to confirm my suspicion regarding the one I installed yesterday.