RV Water Pressure

[rudyhehn]

9 years ago when we were first into using our rv, I saw no need for a pressure regulator. Bad mistake. Pressure at one campground was probably 90 - 100, and the next day I had a leaking water pump. Fortunately I did not break a water line, and one of the first repairs I learned how to do was replacing a water pump. Since then I use a regulator and have had no problems. Hopefully others can learn from my mistake. The issue of high pressure damage is not just theoretical, it really happens.

[Old-Biscuit]

Originally Posted by Mr.Locksmith

ALWAYS, ALWAYS, ALWAYS use a regulator!
Just out of curiosity, I purchase a water pressure meter which has an extra pointer that shows the maximum pressure reached since the last reset. I attach this meter before my regulator just to see what's going on. I'm surprised at how many campgrounds I been at where the local water pressure is over 100psi. The maximum I've seen so far is 112psi. For this reason I ALWAYS us a good quality pressure regulator with a gauge attached.

And that is why I only use the fresh water tank and pump
*Consistent water pressure/flow regardless of where we are
*Easy to flip switch off when we go to bed, leave RV so no water leak surprises
*Pump short cycles when no demand then there is a leak -- find/fix it

[followingsea]

Originally Posted by Mr.Locksmith

ALWAYS, ALWAYS, ALWAYS use a regulator!
Just out of curiosity, I purchase a water pressure meter which has an extra pointer that shows the maximum pressure reached since the last reset. I attach this meter before my regulator just to see what's going on. I'm surprised at how many campgrounds I been at where the local water pressure is over 100psi. The maximum I've seen so far is 112psi. For this reason I ALWAYS us a good quality pressure regulator with a gauge attached.

Did you purchase a dual band pressure strip chart recorder to measure the piping pressure in the RV and at the campground hose bib?

No! Then you do not know how the pressure regulator works.

There was a design change on my system at a nuke plant to use a pressure regulator valve to keep the safety cooling water system full of water when it was not running. I was handed a test to show the pressure regulator worked.

I had the test back saying it was wrong. A little later I found folders on my desk saying make it right. I did but I handed it to another system engineer because I was going on vacation. That engineer said the test was wrong. So I added a step to record how long it took for pressure to drop.

So I come back and ask how the test went. They were still running it and waiting for the pressure to decrease and was sitting at 150 pisg or design pressure controlled by the relief valve.

If you put colder water in a system it will expand causing pressure to increase until it leaks through valves. I had just fixed all my valves.

Thermal expansion is a big issue in power plants.

RVs not so much.

Back to my original advice. Enjoy your RV and do not worry about water pressure.

[followingsea]

Originally Posted by Old-Biscuit

And that is why I only use the fresh water tank and pump
*Consistent water pressure/flow regardless of where we are
*Easy to flip switch off when we go to bed, leave RV so no water leak surprises
*Pump short cycles when no demand then there is a leak -- find/fix it

BZ!

[DutchmenSport]

Hi! Me again! I read all the posts. OK, sorry for a little confusion I may have created.

I'll clarify....

If you are wanting to know the max (SAFE) PSI your camper can handle, THEN use the PSI numbers labeled on your fresh water pump. Manufacturers are not going to install water pumps that exceed the water pressure capabilities of the plumbing installed. So, if you are looking for a safe max pressure, then use the max number on the water pump. You won't go wrong.

Now yes, I agree, .... PEX plumbing can handle a much higher pressure than that.... I agree ..... but also consider the faucets, valves, and everything else too. Going with the max psi labeled on your water pump will not take you in a wrong direction. Is a safe number to work with.

And again, if the water pressure at the park is up and down and it drives you batty, THEN consider using your on-board water tank and pump. The water flow will be more consistent (maybe noisy, but consistent) no matter how much the water at the park changes.

[Unplanned Tourist]

I have a good adjustable water pressure regulator mounted on the intake for city water. It's set at 50 psi. I always carry at least 1/4 of a tank of fresh water. When I get to a serviced site I hook up the power and that's all until I need more water. Then I'll put some water in my fresh tank. I always run off my pump.

If we're going to a place with questionable water quality, I would rather top up my tank with good known water and only use the questionable water for flushing my black tank before we leave.

By using just the pump I can hear if there's a leak anywhere. But that's just me.

[Gary RVRoamer]

Originally Posted by kv1361

You should never run your water pump in combination with city water pressure. the water pressure will back flow against the pump diaphragm and wear it out prematurely.

Not really. There is always back-pressure against the pump diaphragm, even if no city water in use. The pump runs until it builds enough back-pressure to make it shut off, typically 45-55 psi. Sitting there with that 45+ psi pressure on it is the normal state of affairs for a diaphragm pump.

[kv1361]

Originally Posted by Old-Biscuit

Not really.........

Pump discharge and city water inlet supply the SAME cold water line which supplies the hot water system

When on City Water the pump is pressurized (by design) and the pumps internal check valve (diaphragm) is closed to stop backflow thru pump.
Turning pump switch ON while connected to City Water does nothing unless City Water pressure drops below pump pressure switch start setting (it senses system pressure)

Pump can even run DRY by design and not cause damage as the water flow is not required for cooling

That disposition was directly from Shurflo following an issue where the fresh water tank was filling while using city water. They asked if the owner (not me) was using the pump during city water use to increase the pressure. I suspect the check valve was allowing a backflow.

[Gary RVRoamer]

Originally Posted by kv1361

That disposition was directly from Shurflo following an issue where the fresh water tank was filling while using city water. They asked if the owner (not me) was using the pump during city water use to increase the pressure. I suspect the check valve was allowing a backflow.

No doubt it was, but that doesn't mean the leak was caused by operating the pump with city water pressure present. Correlation is not causation. The diaphragm is under pressure at all times when city water is connected, whether the pump is on or not. And also under pressure any time pump is on, whether city water is connected or not. It's the natural state of affairs for a diaphragm pump and Shurflo needs to design for it (if they haven't already).