Exploding water filter

nomad297 wrote:
Whether you have a pressure regulator, or not, your RV plumbing supply is a closed system -- there is a check valve preventing back flow to the city connection. When your water heater heats, the pressure in your system increases and it will only relieve at 150 psi when the water heater T&P valve opens up. So....no matter what you do, your pressure will increase above your regulated pressure if you are using a water heater.

Bruce

Sorry, not fully true.

MOST (if not all) water heaters actually have a CHECK VALVE installed on the COLD WATER side of the heater.

Many people do not realize this since the check valve is actually HIDDEN and looks like a simple plastic male to male pipe fitting sticking out the back of the tank.

Looks like THIS

and now days you may find a newer version which looks like THIS

You can verify if your system has a check valve on the cold water inlet by pressuring the system (city water port)with water.

Then turn off the water source on the inlet (inlet also has a check valve which WILL hold the water pressure from leaving via the city water port).

Open the COLD water and let the pressure bleed down then close the COLD water.

Now open the HOT water side and if you still have pressure then you HAVE an inline check valve in the cold water side of the water heater..

No pressure on the hot side then there is no check valve..

I am aware of the check valve since mine had a spring loaded one which would tend to "sing" extremely loud when any hot water was being drawn.. I replaced mine with a brass swing check valve and no more "singing".

There SHOULD be a check valve since it is a part of the safety of your water heater system. Without the check valve the T&P (Temp and Pressure relief) valve would never ever trip creating a dangerous situation to say the least..