Noob water heater fill question.

NMDriver wrote:
You should not open the pressure relief valve when filling the tank. You need some air in the top of the tank to allow for expansion as the water heats. If you do not have any air then you may have the relief valve open and spew hot water. Air in the top of tank is how the system is designed to work. You are just shortening the life of the relief valve and asking for leaks by bleeding all the air out of the tank.

X3

NMDriver wrote:
You should not open the pressure relief valve when filling the tank. You need some air in the top of the tank to allow for expansion as the water heats. If you do not have any air then you may have the relief valve open and spew hot water. Air in the top of tank is how the system is designed to work. You are just shortening the life of the relief valve and asking for leaks by bleeding all the air out of the tank.

This. When water starts coming out of the faucet. Full

You should not open the pressure relief valve when filling the tank. You need some air in the top of the tank to allow for expansion as the water heats. If you do not have any air then you may have the relief valve open and spew hot water. Air in the top of tank is how the system is designed to work. You are just shortening the life of the relief valve and asking for leaks by bleeding all the air out of the tank.

DCamp84 wrote:

corvettekent wrote:
I would think that you need a hot water faucet turned on to let the air out of the tank.

I have been leaving the pressure relief valve on the wh open untill water starts flowing out. That is how I have been gauging its full so I can turn the heater on.

I do this to get air out of the tank, then I open the faucets to get air out of the lines. I don't drain water between outings, and I don't have air in the lines next time out. I only drain the whole system when I winterize.

OP, as long as your bypass valves are in normal position, your hot water tank will fill from whatever water source you're using, city for FW tank.

Mark

DCamp84 wrote:

corvettekent wrote:
I would think that you need a hot water faucet turned on to let the air out of the tank.

I have been leaving the pressure relief valve on the wh open untill water starts flowing out. That is how I have been gauging its full so I can turn the heater on.

I have done it both ways. Really don't see and advantage or disadvantage to either. I also leave my hot water tank full once I fill it the first time in the spring until I winterize in the fall.

corvettekent wrote:
I would think that you need a hot water faucet turned on to let the air out of the tank.

I have been leaving the pressure relief valve on the wh open untill water starts flowing out. That is how I have been gauging its full so I can turn the heater on.

corvettekent wrote:
I would think that you need a hot water faucet turned on to let the air out of the tank.

That is correct. When setting up camp, once water is available to the trailer (either city is hooked up OR fresh water tank has water available for the pump), go thru the process of opening your faucets and letting the air out. With a hotwater faucet open, the system will pull water from the hotwater tank which in turn pulls it from either the FWtank/or city.

CAUTION: Do not turn on the switch (Gas or Electric) until after you have pulled water into the tank. It is not advisable to heat an empty tank. With a hot water faucet on, air stopped spewing, and water now running. The hotwater tank is filling.

ALTERNATE: If you didn't drain your hotwater tank since the last outing then it most likely still has water in it. You still need to get the air out of the lines though.

I would think that you need a hot water faucet turned on to let the air out of the tank.

"If I switch the valve in the docking station from tank to city does that direct the water directly into the water heater to fill it assuming"

Maybe, maybe not.

The only way to fill the WH (water heater) tank is to have the WH bypass valve in the correct/fill position.