Hot Water Issue

[KdeAce]

2000 Fleetwood Flair 25Y

My hot water heater IS working. Supposed to be Hot on LEFT, cold on RIGHT at all faucets. Red tape on lines indicate hot water lines going to the correct faucet.

With Bypass valve in OFF - bypass - (vertical position) I have NO hot water to faucets, but I have full water pressure from rv park water supply.

With Bypass valve in ON - normal - (horizontal position) I have water on hot side, but it is cold, and NO water on cold side. 

If I turn on the water pump, I have very low pressure on both faucets, Cold on left - Hot on right (Everywhere including the toilet) eventually there is air in the lines till the hot water stops. Pump never stops running.

Any Answers to my issue?

Thanks

[Kirk W]

Welcome to the forums! I'm sorry that it was problems that brought you here, but we are still happy that you have joined us. It sounds to me like you may have 2 different issues so I'll address them separately. 

In reading over your description of the bypass issue, I am convinced that you have a single valve, bypass system that probably looks similar to this one.

In this system, the valve position shown will send cold water into the water heater tank to be heated and when a hot water faucet is opened the heated water leaves via the red line on the left, pushed out by the pressure of the incoming cold water. Turning the valve to the left takes the cold water and rather than send it into the tank, it will bypass the water heater and to out through the red line to the hot water faucets. What makes this work is that there is a check valve between the connection from the bypass and the outlet of the water heater to prevent the water from the bypass from entering into the water heater but cause it to go out into the red hot water lines. If you look closely at the connections on the left side above the white T fitting there is a shiny brass fitting and that is probably the check valve. I suspect that your water heater check valve is stuck closed and will not allow the water to exit the water heater tank. That is a fairly common problem and is more common if the owners do not drain and flush the water heater annually to remove the buildup of calcium that is normal inside of water heater tanks. 

On the water pump running issue, does your RV have a valve to fill the potable water tank from the city water connection? If it does and if that valve is open, the water pump will draw water from the bottom of the tank, push it out into the water system and the open tank fill valve then allows that water to return to the tank, only to be pumped back into the system again. That valve would be the first thing that I would check. 

[Domo]

Some water heaters do have a one-way check valve on the output side - I remember reading that some folks have had that valve stick in the closed position.

Just thinking - that could give the symptoms OP is describing...