Having had the fresh water tank overfill issue (usually fixed by relieving pressure on the valves, cycling the valves then reconnecting the city water). I recently had a new issue.
Thanks to Indiana State Parks, I had two occasions recently to use my freshwater tank for 2x week long stays.
Never having his issue before while on pump/fresh water tank usage, i had two symptoms: 1)my fresh water pump cycled periodically., 2)When the pump was OFF i noticed the plumbing did not hold pressure like it used to a year ago.
I ripped the basement apart and checked nearly all the fittings/fixtures to ensure I didnít have any leaks. The only one I didnít check was the shower fixture.
I also ensured I bled the washer/dryer connections to ensure the pump wasnít pushing against air in the lines.
The Sureflo manual indicates the pump will cycle periodically if there is scale buildup on the check valve inside the pump.
At this point I assumed the pressurized size of the plumbing was leaking back into the fresh water tank. That would explain both symptoms above given i had checked for leaks.
I could take the pump apart and clean/replace the check valve or just add threaded check valve Camco 23303 1/2" Back-Flow Preventer - Lead Free https://www.amazon.com/dp/B000EDUTN6..._pGgQDb01P973D
In looking through previous posts on this subject I see a mix of some put it before the strainer and some after the pump. While the 2nd symptom above would be solved, seems to me if it was after the pump the pump would continue to periodically cycle since the pumpís check valve would continue to leak.
On the other hand, some posters say when installed before the strainer they can not get water flow as the check valve constrains the supply plumbing too much.
Any experiences to share from you folks who have installed the separate check valve?