The older trailers had the three VALVE Water Heater BYPASS setup...
Looked something like this google photo
The operations is depicted in this pictorial
The basic water flow diagram for the older trailers is much like this drawing...
This setup only allows the fresh water tank to be manually filled and the only time you use the Water Pump is when you have water in the fresh water tank.. The city water inlet provides the necessary water pressure when not using the water pump.
Newer trailers now have switch valves to allow the fresh water tank to be filled from the city water inlet. Have no experience with the newer trailer water flow setups...
Roy Ken
My Posts are IMHO based on my experiences - Words in CAPS does not mean I am shouting
Roy - Carolyn
RETIRED DOAF/DON/DOD/CONTR RADIO TECH (42yrs)
K9PHT (Since 1957) 146.52M
2010 F150, 5.4,3:73 Gears,SCab
2008 Starcraft 14RT EU2000i GEN
2005 Flagstaff 8528RESS