Proper Spot for Water Pressure Regulator

I made the mistake of putting it on the TT inlet and the next morning my hose looked like it swallowed a rabbit, so always put it on the faucet

lawrosa wrote:

Let me ask ya all..

When your water heater heats up, how much pressure does it increase you rv's plumbing from thermal expansion???

becuase when you add these pressure regulators they act as a check valve. Now you make your water system a closed system... So the thermal expansion has no where to go. So when heating hot water you can build PSI in the camper up up up to way over 100 psi..

Without the reducer/.check valve the expansion will push back to the campground water system..

Since you asked...

Newer RV's have a backflow check valve installed at the city water connection. Without that valve, your water pump could pump the water from your FW tank back into the CG system. Not nice.

Also even though water lines have a high pressure rating they connect to the system via untested fitting. Excessive pressure in the line might not burst the line but will usually cause a fitting to spring a leak or come apart flooding the trailer.

CG don't guarantee their water pressure so having a cheap $10 pressure regulator attached to the CG spigot is very cheap insurance.

In one park we hosted at had backflow devices on the end of the spigot, at times the filter screen on the pressure regulator interferes with the operation of the backflow device stopping water flow. I put mine on the trailer supply side of the Y.

Old-Biscuit you beat me to the punch. Iawrosa says he has been a plumber for 30 years. I am glad he is not my plumber. As I said when I got rid of the plumber that worked on my house, “I guess you don’t have to be too smart to be a plumber.”

Anyway, to answer Grumpy2day’s question, like all the others have said here, it goes on the spigot side.

Fulltimers wrote:
Old-Biscuit you beat me to the punch. Iawrosa says he has been a plumber for 30 years. I am glad he is not my plumber. As I said when I got rid of the plumber that worked on my house, “I guess you don’t have to be too smart to be a plumber.”

Anyway, to answer Grumpy2day’s question, like all the others have said here, it goes on the spigot side.

Thats how it works in residential applications. Ive been on 1000's of calls for failed exp tanks on closed loops systems. On arrival the relief valve of water heaters spewing all over the place.

Why would a RV be any different?

Why do you think your relief valve weeps in your RV? Mine does when water is heating..

You can flame me all you want. I have thick skin... Im just bringing up a valid point..

I did fail to realize there is a spring check in the water inlet:E

More so why a accumulator or exp tank is beneficial...

As for thermal expansion and the regulator acting as a check valve, all RVs I've seen for the last 20 years have a check valve right at the hose connection so you already have a 'closed system'. If not for that check valve, if you weren't connected to city water, you'd have a stream of water spraying out of the hose connection as soon as you turned on your pump. My experience is that all the $10 regulators, although they do the job, also are very restrictive and make for a really weak shower experience. The good, larger units with the valve seem to pass a much greater volume of water.

OK...so I use a short piece of hose to first connect to my canister water filter set up, then the regulator and then into the water softener and finally into the RV. That's only if I feel like hooking it all up. :-)

lawrosa wrote:


Thats how it works in residential applications. Ive been on 1000's of calls for failed exp tanks on closed loops systems. On arrival the relief valve of water heaters spewing all over the place.

Why would a RV be any different?

Why do you think your relief valve weeps in your RV? Mine does when water is heating..

You can flame me all you want. I have thick skin... Im just bringing up a valid point..

I did fail to realize there is a spring check in the water inlet:E

More so why a accumulator or exp tank is beneficial...

I do find the accumulator tank I installed in our RV beneficial in reducing pump starts and the need to re-establish the heater tank's air pocket, but as far as the water heater itself goes in the absence of an accumulator, if the relief valve is weeping when heating, then the air pocket in the tank is gone. Simply draining the tank fully with the relief valve open will re-establish the air pocket as noted in the owners manual trouble shooting section for most. Not all residential systems have an accumulator tank either.

I have seen the geyser effect of a hose blowing while the occupant was out. I have also stayed at plenty of CG's, including the state parks we use every year that have very high pressure. Some even post signs to a.bout it and tell you to use a reg.
I have never seen an RV with a built in regulator. Maybe some high end? Certainly not the norm.
Anyone who even remotely suggests you'll never need one just hasn't been around.

I used to keep it permanently attached to the camper so that I could never forget it at a campground. But now I don't have as nice of a water bay and it goes on the spigot.