City water plus water pump

[don8ch]

This past weekend we were camping at a campground with very poor water pressure. While waiting an interminable amount of time to fill the sink I reached over and turned the water pump on (the fresh water tank was approximately half full) and the desired result was obtained. My wife was concerned that I might damage the pump by having both city water and the water pump operating simultaneously. Is this a no-no?

Thanks,
Don

[OneRVer]

I am not sure if it is no-no or not but when my wife takes a shower she always turns the pump on with the city water. I believe the water flows thru the pump either on city or tank. I found this out when I had a leak on the inlet to my pump and I found the leak while on city water and the pump off.

I do not have a Newmar but I suppose they are plumbed the same.

[GaryKD]

Hi Don,
I do the same as you. If the CG has poor water pressure, I use the coach pump to help out. This is one reason I travel with a full tank of water.

[Route 66]

It is not a problem.

[wa8yxm]

Will using both city water and the water pump at the same time damage the pump.
NO, absolutely NO chance of that happening.

WHY:

The pump has two things in it that are of importance.

1: A check valve,, This prevents water from flowing back into the tank.. NOW ANY time you are hooked to city water this check valve is doing it's thing, don't matter if the pump is on or off it's doing it's thing.

2: A pressure switch, if the city water pressure exceeds the pump pressure, it will not even let the pump turn on

The city water inlet also contains a check valve

So if the pump pressure exceeds the city water pressure, then city water is turned off.

So you see, it is impossible to use both city water and pump (Stored) water at the same time cause whichever one has the higher pressure will simply turn off the other.

(Note there is a very minor exception to that last sentence. . but it's not worth explaining)


There is, however, one way the pump CAN be damaged by city water.. Just one.

I will soon park in a place where the info sheet comments about very high water pressure (When I was there last year it was in the 80PSI range but they have logged pressures over 120 PSI in the past)

That,, kind of pressure can damage several things inside your house, Including the toiilet valve, and the water pump.. (Don't matter if it's on or off) What it will NOT damage, is the pipes. (They are good to 150PSI or more)

[Brigadoon]

Speaking of high water pressures, we stayed in a park in Cedaredge, CO that was reading 90 psi. They advised that they had observed 120 psi also.

[Shaun and Amy]

Quote:

Originally Posted by wa8yxm WHY: The pump has two things in it that are of importance. 1: A check valve,, This prevents water from flowing back into the tank.. NOW ANY time you are hooked to city water this check valve is doing it's thing, don't matter if the pump is on or off it's doing it's thing. 2: A pressure switch, if the city water pressure exceeds the pump pressure, it will not even let the pump turn on The city water inlet also contains a check valve So if the pump pressure exceeds the city water pressure, then city water is turned off. So you see, it is impossible to use both city water and pump (Stored) water at the same time cause whichever one has the higher pressure will simply turn off the other.)

I thought check valves only worked in one direction. I can understand that a check valve will stop, let's say, stored water from being pumped back into the city water, but how does it stop the city water from flowing into the RV? To me, this would require either two check valves, at different settings or an electronic valve. So, are there really two check valves on the City Water connection? I didn't realize this. Or am I not understanding this correctly?

Interesting........Shaun

[RickO]

If we're in a park with low pressure we always turn on the pump and I always thought this to suplement city water but I guess I was wrong on that front. At any rate, if the pump engages while hooked up to city water the city pressure is pretty low.

Rick

[read & learn]

Think of a Y one side from tank the other city water the back flow is on the tank side

["007"]

Check valves or not your water pump will add preassure to your water system as long as you have water in your fresh water tank, the pump is adding water into system from tank not from the city water line.