Typical RV Trailer water system.
City water connection feds cold water system directly and ties into same cold water line water pump feeds.
Off of the cold water system is a inlet to water heater which then feds hot water system
City water connection has a check valve in it to prevent backflow out connection when using pump.
Pump has an internal check valve to prevent backflow thur pump when using city water.
When connected to city water pump can be ON but wouldn't run due to pumps pressure set point for starting.
IF city water pressure should drop below pump start set point pump would run and supply system until city water pressure recovered. Provided you have water in fresh water tank
I would make two suggestions:
1) get and use a good quality water pressure regulator---WATTS are good and rebuildable. Set it for 50# Static (no flow)
Use it whenever connected to RV...even black tank flush system (different hose....regulator at supply with a 'Y' for the two different hoses.
2) fill fresh water tank and use it/pump vs city water
Had a leak while sleeping and city water connected......flooded RV $6000 PLUS in damages/costs
Now only use pump/fresh water tank cause if a leak happens I can hear pump running
Plus showed up at CG once w/o full fresh water tank and CG water supply main line broken....no water available.
Is it time for your medication or mine?
2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
2007 HitchHiker II 32.5 UKTG 2000W Xantex Inverter
US NAVY------USS Decatur DDG31