Adjustable water regulator

[nam.64]

This morning I purchased a water regulator with a pressue gauge. I visited with a fellow RV'er for hints for installation. When we opened his plumbing the bay door the first thing I noticed was his pressure gauge was pegged past the 120 PSI point. He said it was because he had used his shower before he left the coach. He went on to say as the water heats pressue builds throughout the system and until released it will stay at the 120+PSI. He opened a valve in the bay and the pressure dropped to 50 PSI. QUESTION: Is this normal?? Is there a relief valve that can be inserted into the system to prevent this pressure build up?? The "pop off"
valve at the water heater is rated at 150 PSI providing no relief of pressure until the entire system would already be jeopardized.

Thanks in advance

nam.64

PS: Happy Fathers Day to all us Dad's and our Dad's

[ralper]

I am retired after 50 years of plumbing and heating.

IMHO every RV with a water heater should have an accumulator (pressure) tank to stop this sort of thing.
There is supposed to be an air bubble in the top of the water heater for expansion but it never works and I think it is a dangerous thing to rely on.

The RV companies either go about this in ignorant bliss or more than likely are cutting corners for a larger profit. They should also build in a water pressure regulator.

[Gary RVRoamer]

There is no normal reason for pressure to build up like that in an RV system. The air "head' in the water heater is normally sufficient to cushion the modest pressure build-up from the heater. Many (but not all) RVs have a check valve on the cold inlet to the tank anyway and this prevents the pressure from pushing back into the rest of the system.

My guess is that the rig you looked at had lost the air cushion in the water heater tank. It is easy to restore by letting the tank cool off, shutting off the external supply (pump or city water), opening a faucet to relive any internal pressure, and then opening the PT relief valve to let water drain out to the level of the PT valve.

[ga traveler]

The simplest way to keep a air cushion is to drain the water hose each time you put it up. When you get to the next campground, hook up the hose and turn on the hot faucet. the air will go into the HWH and replace the air cushion.