Help with stuck water pump check valve

[Billy S]

I know this thread has been discussed over and over, but I would like to see if there is ever going to be a fix. Reset the water pump check valve, yes, that works, but I don't call this a fix, if I have to do it again and again. We have had 7 different Motorhomes, after having travel trailers. I have never seen this before. When we first got the Motorhome, the water pressure with the pump was low, so I cleaned the screen, it was clogged so full of plastic and junk, I thought I would destroy the screen.
We went camping Saturday water was fine, until Monday we went shopping, came back to the RV, saw water under the MH, checked and yes the fresh water tank was overflowing. So I did the reset, drained some water.
Take it back to the dealer, yes and wait till???? I do almost all my own work.
2020.5 Isata 3

[ependydad]

Manually add another check-valve:
https://learntorv.com/water-pump-check-valve/

[bclemens]

Originally Posted by Billy S

I know this thread has been discussed over and over, but I would like to see if there is ever going to be a fix. Reset the water pump check valve, yes, that works, but I don't call this a fix, if I have to do it again and again. We have had 7 different Motorhomes, after having travel trailers. I have never seen this before. When we first got the Motorhome, the water pressure with the pump was low, so I cleaned the screen, it was clogged so full of plastic and junk, I thought I would destroy the screen.
We went camping Saturday water was fine, until Monday we went shopping, came back to the RV, saw water under the MH, checked and yes the fresh water tank was overflowing. So I did the reset, drained some water.
Take it back to the dealer, yes and wait till???? I do almost all my own work.
2020.5 Isata 3

It might also not be the check valve. If the Anderson Water Selector has a leak at the O-ring, this can happen too.

I assume you have a pressure regulator? High pressure is the primary cause.

[Billy S]

Yes I have a water pressure regulator. When I first hook up the water, I turn water on, than when the pressure stops, I turn the water off, if the water is going in the fresh water tank, the pressure drops, so I do the do the check valve thing. I think the valve system in the water pump is flawed, or why would so many threads show up all the time. As far as adding a check valve, I hardly have room to get my hands close to the water pump, don't know if there is room to add anything.

[5picker]

1st, my advice is never leave the R/V for any length of time without turning off the water supply. There are too many reports of what is referenced in this thread as well as, other valves (toilet comes to mind) malfunctioning with very unfortunate results. My Uncle once opened his entrance door to hundreds of gallons of water pouring out the door due to a stuck toilet valve that overflowed the toilet while we were gone for the afternoon.


2nd, I've got my own pressure testing going on here at our winter stay campground and have a thread about water system pressures rising when the air pocket/expansion space in the water heater depletes.

When the air pocket in the water heater is gone, (simply from regular use) I regularly see pressures right around 100 P.S.I. Often these pressures are reached once the system sets for an hour or couple of not cracking a faucet.

I'm beginning to believe this may be contributing to overcoming the check valve in the pump.

Just some food for thought....

[bclemens]

Originally Posted by 5picker

1st, my advice is never leave the R/V for any length of time without turning off the water supply. There are too many reports of what is referenced in this thread as well as, other valves (toilet comes to mind) malfunctioning with very unfortunate results. My Uncle once opened his entrance door to hundreds of gallons of water pouring out the door due to a stuck toilet valve that overflowed the toilet while we were gone for the afternoon.


2nd, I've got my own pressure testing going on here at our winter stay campground and have a thread about water system pressures rising when the air pocket/expansion space in the water heater depletes.

When the air pocket in the water heater is gone, (simply from regular use) I regularly see pressures right around 100 P.S.I. Often these pressures are reached once the system sets for an hour or couple of not cracking a faucet.

I'm beginning to believe this may be contributing to overcoming the check valve in the pump.

Just some food for thought....

^^THIS^^ Solid Advice!

[Billy S]

I do turn my water off, when it is hot (South Texas heat) but I don’t when it is cooler, my bad. This still doesn’t fix the problem.

[sasch]

So, how do I “reset the water pump Check Valve?”

[ependydad]

Originally Posted by sasch

So, how do I “reset the water pump Check Valve?”

Flip back and forth between city water and the water pump:

- turn off city water, turn on water pump
- run water at a faucet
- turn off water pump, turn on city water
- run water at a faucet

Do this 2 or 3 times and it seems to reset the check valve in the pump.

[BudC]

Originally Posted by ependydad

Manually add another check-valve:
https://learntorv.com/water-pump-check-valve/

The link reference says add a check valve on the inlet side of the pump. If you don't want water back flowing through the pump why not add the it to the outlet side???

[ependydad]

Originally Posted by BudC

The link reference says add a check valve on the inlet side of the pump. If you don't want water back flowing through the pump why not add the it to the outlet side???

I got the reasoning from posts here.. I forget why. Something about pressure on the pump.

[Larry-NC]

Originally Posted by Billy S

I do turn my water off, when it is hot (South Texas heat) but I don’t when it is cooler, my bad. This still doesn’t fix the problem.

Billy, you've got it backwards. The high pressure arises when cool water is heated in the water heater and expands. The cooler the water, the more the expansion. Since the campgrounds put those backflow preventers on the water spigots, there's no place for the volume to go and the pressure rises. (Eventually, if it gets to 150 psi, the Temperature & Pressure valve on the water heater will open.)

The same thing happens with residential systems.

[Larry-NC]

This is about the same post I made yesterday.

You can add a second one-way valve (check valve) at the water pump. Here are some typical ones.

Pick one that matches your plumbing. Do you need two male threads or one male and one female?

Put it on the output side of the water pump (going to the RV plumbing, not to the fresh water tank. Make sure the arrow on the fitting points AWAY from the pump (direction of water flow).

[5picker]

I've wrestled with check valve placement for many years originally thinking if on the outlet side (pressure) of the pump it would protect the pump and I had concerns of the pump having to overcome the check valve to suck water.

I've since changed my thought and installed my last one on the inlet side (suction) of the pump once it was pointed out that when NOT connected to city water, if the pumps internal check valve leaks back, with the new check valve on the outlet side of the pump, pressure will bleed off back to the tank and the pump may run every few minutes to repressurize. I didn’t experience any detriment to the pump sucking water with it on the suction side.

I also originally had concerns of pressure on the suction/strainer but have since read manufacturer specs stating they are good to 150 P.S.I.

I guess if one really wanted optimal placement it would be installed between the pump and the suction/strainer but that would require an extra thread gender adapter.

Just my thoughts...

[Larry-NC]

Originally Posted by 5picker

I've wrestled with check valve placement for many years originally thinking if on the outlet side (pressure) of the pump it would protect the pump and I had concerns of the pump having to overcome the check valve to suck water.

Help me on this.

The pump is designed to work against pressure on the output side. If the pump's cutoff is, say, 40 psi, it will be pumping against 35, 36, 37, 38, and 39 psi before it shuts off. It certainly shouldn't have a problem with the few psi it takes to overcome the spring in the check valve.

On the input side, the only resistance the pump has is the filter and maybe 12" of lift. I don't know how much suction it's designed for. (It pulls antifreeze pretty well, but in our rig the fluid level is actually about the same height as the pump.)

I've read occasional posts about pumps not priming. That biased me against recommending putting it on the suction side. (I kinda suspect that those posters had vacuum leakage either at the filter housing or the winterization valve, but don't know for sure.)

Your test seems to show that either side will work.

[5picker]

Originally Posted by Larry-NC

Help me on this.

The pump is designed to work against pressure on the output side. If the pump's cutoff is, say, 40 psi, it will be pumping against 35, 36, 37, 38, and 39 psi before it shuts off. It certainly shouldn't have a problem with the few psi it takes to overcome the spring in the check valve.

On the input side, the only resistance the pump has is the filter and maybe 12" of lift. I don't know how much suction it's designed for. (It pulls antifreeze pretty well, but in our rig the fluid level is actually about the same height as the pump.)

I've read occasional posts about pumps not priming. That biased me against recommending putting it on the suction side. (I kinda suspect that those posters had vacuum leakage either at the filter housing or the winterization valve, but don't know for sure.)

Your test seems to show that either side will work.

Sorry Larry,
I worded that poorly and when trying to justify placement on either side, I meant to say (but forgot to include) in the first paragraph...

I've wrestled with check valve placement for many years originally thinking if on the outlet side (pressure) of the pump it would protect the pump and if on the inlet side, I had concerns of the pump having to overcome the check valve to suck water.

Been a long day...

[Larry-NC]

Originally Posted by 5picker

Sorry Larry,
I worded that poorly and when trying to justify placement on either side, I meant to say (but forgot to include) in the first paragraph...

I've wrestled with check valve placement for many years originally thinking if on the outlet side (pressure) of the pump it would protect the pump and if on the inlet side, I had concerns of the pump having to overcome the check valve to suck water.

Been a long day...

We're definitely in agreement on this one.

I've had days like that, too.

[Billy S]

What does this have to do with my problem? We have an on demand water heater. I turn the water off, when we will be gone for very long, on the day I had the problem, we were not gone very long. Like I said, this is our 7 Motorhome, after travel trailers, I never had this problem before, so there is a problem with the valve body inside the pump. I have never seen this problem in other RV forums.

[Larry-NC]

Originally Posted by Billy S

What does this have to do with my problem? We have an on demand water heater. I turn the water off, when we will be gone for very long, on the day I had the problem, we were not gone very long. Like I said, this is our 7 Motorhome, after travel trailers, I never had this problem before, so there is a problem with the valve body inside the pump. I have never seen this problem in other RV forums.

Billy, take it easy and read this carefully. It will explain the previous comments and why it might not apply to you.

Sometimes the water pump check valve will only leak under high pressure--pressure well above the typical 40 psi--but not at lower pressure. Sometimes they leak because the check valve was defective at install or damaged during assembly. Sometimes it's because a foreign object is preventing the valve from closing (seating) properly.

You mentioned that your RV came with lots of undesired foreign matter in the filter on the input to the pump. It's definitely a possibility that there's an object in the check valve that simply won't flush through. Your options are to take the pump apart and clean it, replace the pump, or put an aftermarket check valve in line with it (or have someone do one of these it it's still under warranty).

The water heater posts raise the possibility that a tank-type heater can raise the pressure in the system way beyond the 40 psi water that's coming in. I believe you are right--that not a likely cause with a tankless heater. The threads in this forum have a habit of drifting off-topic if they get too long, and this is one of those instances.

[5picker]

Originally Posted by Billy S

What does this have to do with my problem? We have an on demand water heater. I turn the water off, when we will be gone for very long, on the day I had the problem, we were not gone very long. Like I said, this is our 7 Motorhome, after travel trailers, I never had this problem before, so there is a problem with the valve body inside the pump. I have never seen this problem in other RV forums.

Also to add to what Larry said...

This last post of yours is the first any of us (besides you) knew the water heater was a tankless model. Tankless models are less common, so many of us when giving advice, use the model of most common.

I agree... the higher internal pressures from a lack of air space does not apply to tankless models so you need to look at the pump's check valve and not the possibility of high pressures from the water heater.

Sorry for the confusion.
I'll bow out now...