Purpose of Hot Water Heater Check Valve??

[ladder16]

I have low hot water pressure throughout my Precept. After reading many helpful posts and flushing the hot water tank I believe I need to replace the check valve. Can someone explain why this valve is needed? It is located at the hot water outlet side of the heater. I believe it keeps the hot water in the pex from going back into the hot water tank? I could understand it more if it was on the cold water inlet side to keep the hot water in the heater from back feeding into the cold supply. Do I even need the check valve?

[JFlightRisk]

It may be a necessary valve, depending on the configuration of your plumbing. The hot side outlet check valve is to prevent antifreeze from filling up the water heater when you winterize, that's if you have a 1 or 2 valve bypass system.

On some RVs, the cold water line passes right past the heater, and there can be as little as 2 inches of pipe between the "T" in the cold line, and the water heater bypass valve.. As the water heats up, it expands, and hot water is pushed back into the cold water lines.

It may or may not be necessary on your particular rig, but it does have a purpose, like the other 2 check valves, in the water pump, and the city water inlet. If your RV has a plastic check valve at the water heater, replace it with a brass one. It'll last longer.

[RVermont]

On my unit 2018 Seneca with 4 valve settings when you select winterize on the valve set up the system shuts off the supply to the hot water tank and opens a path to the hot water fixtures. Mine does not have a check valve and you have to wait to drain the hot water heater until after you have treated the rest of the water system or the solution will fill the heater. With a check valve you can drain the whole system and nothing will get into the heater unless your valve fails.

Here is drawing I did on my unit. I added two shut off valves so I can drain my heater but still have water or antifreeze in the system

[ladder16]

Thank you both for your replies! I have had several Jayco units and the hot water tank always had bypass valves behind them (and never a problem). My Precept has the 4 valves and I appreciate the drawing and I will change the valve to brass.