Correct type of H2O valve

[Gary Petersen]

2002' Signature:

Our current valve labeled  Fresh Water Fill is leaking at the handle stem. When this valve handle is rotated from vertical to the horizontal, it points to "Nine O'clock" and to a label which states, "Fresh Water Fill Open". When I rotate the handle back to the vertical position, it points to a sign which states "City Water Closed". I pulled the panel-cover to find a three port valve connected to two separate blue PEX lines with the central port dedicated  to the entering garden hose fitting for fresh water access. I am having trouble understanding the exact port function in each position of the handle. The port on left feeds directly into a brass, Back-flow prevent (BFP)  valve just prior to it connecting to the blue PEX pipe on the left.                WHY a BFP?           I can't see where that PEX goes but it is heading back towards the Aqua Hot. The blue PEX pipe on the right disappears in behind the Black tank.   Help me understand what all the functions should be:                 1. To provide city water directly to each fixture.                                                           2. Provide a direct pathway to fill the fresh water tank.                                          3. ???? close off, or open, all access, or????

 Ultimately, I need advice selecting the proper replacement valve;                      do I need a L-Port or a T port valve.   At first look, I see some 3 port replacement valves have their handles pointing down over the central access port. Can those handles be rotated 180 degrees and still provide the required pathways and functions?

OK, school me....

 

[jacwjames]

This is a three way valve. 

There is a check valve that prevents water from backflowing to the valve when the water pump is on.  This side provides water to your coach when hooked to shore water.

The other side goes to your fresh water tank and when you are hooked to shore water and turn the valve to that function it fills your tank.

Nothing magical. 

The check valve on my system started to allow water to drip when the pump was on.  I had to screw in a plug to stop this until I could replace. 

Edited June 22, 2022 by jacwjames

[Bob Jones]

It is a 3-way L-port ball valve. If it is leaking at the handle it is likely it has an adjustable packing. This means you can re-pack the valve without removing it........or replacing it.

The check valve (backflow preventer) is there to prevent your water pump from pushing water out the feed line. You can test this with the water hose removed and water in the tank. Turn the pump on and let the system come up to pressure and see if any appreciable water comes out the fill port (where the hose goes). If so, the check valve / backflow preventer is not sealing 100%.

The water flow is written on the handle by means of an arrow. I suggest checking to see if the valve has an adjustable packing and re-packing the valve as opposed to replacing it.

The functionality of the valve is that it chooses EITHER to fill the fresh water tank OR providing direct water pressure to the unit from the garden hose feed port. It directs the incoming water to the left (feeds the unit) or to the right (feeds the fresh water tank).

Edited June 22, 2022 by Bob Jones