city water fills fresh water tank

[drmarylynn]

I have a 2017 Scamp and have been on several trips with it. Everything has worked fine until this trip. After working fine for a week, when I hooked up to city water yesterday water started spraying out all over. I unhooked the hose and figured I'd stop for washers along the way today. However as I was sitting on the picnic bench later I noticed water coming from the overflow outlet under the trailer.

I checked the fresh water inlet and the tank really was full to overflowing! I've never used the fresh water tank and never purposely put water in it. I'm guessing there's something wrong for this to happen. I've no idea how long I've been hauling a tank full of water around. I use a pressure fitting and filter whenever I hook up to city water. (I did not hook up the hose today either. The pump seems to work fine so I'm trying to use up the water that's in there.)

Any suggestions on how to prevent this from happening? Is something broken or is this how it is supposed to work? I'm on the road for three more weeks so hoping it's a fix I can do myself.

[Borrego Dave]

Hi Mary and welcome to FGRV. I don't have a Scamp but I don't think the city water bib is plumbed to the onboard water tank. It should be a separate system. The onboard tank should only be able to be filled from an outside fill hatch. All the water lines are connected at some point to feed the faucets. What keeps the two separate I'm not sure of but I believe there is a check valve behind the city water connection. Others have had problems with it sticking, don't remember the problem it caused but they cleared it by using say a small screw driver to exercise the spring. Some one will be along soon with the fix and cause. I'm interested too....I may have given you bad info. On the plus side, you do have water to use and no interior leaks .

[Gerry]

On my 79 Boler, I took out water tank because it leaked due to road hazard but anyway my Boler only has one water inlet and that was to the tank.
If you want an easy fix for this get a hot water by pass kit...and plumb it into your water system. When you want water to your tank turn valve in that direction...when you want water just to your sink turn valve in that direction.
Simple.

[Eddie Longest]

There was a post about this on one of the forums. The issue is with the check valve in the pump allowing city water to back flow into the freshwater tank. There were procedures to try to reset the pump check valve. If that did not work usually removing and cleaning up the valve would solve the issue. Sorry I can't remember where I saw the post. Try searching the Sureflo or RV pump check valve.
Eddie
The cheap reliable fix is to add a check valve to the output of the pump. Seems like a lot of the newer pumps are having this issue. The threads were on the Escape forum.

[Jann Todd]

Originally Posted by drmarylynn

I have a 2017 Scamp and have been on several trips with it. Everything has worked fine until this trip. After working fine for a week, when I hooked up to city water yesterday water started spraying out all over. I unhooked the hose and figured I'd stop for washers along the way today. However as I was sitting on the picnic bench later I noticed water coming from the overflow outlet under the trailer.

I checked the fresh water inlet and the tank really was full to overflowing! I've never used the fresh water tank and never purposely put water in it. I'm guessing there's something wrong for this to happen. I've no idea how long I've been hauling a tank full of water around. I use a pressure fitting and filter whenever I hook up to city water. (I did not hook up the hose today either. The pump seems to work fine so I'm trying to use up the water that's in there.)

Any suggestions on how to prevent this from happening? Is something broken or is this how it is supposed to work? I'm on the road for three more weeks so hoping it's a fix I can do myself.

There were several answers to this problem in the forum a few weeks ago. Try going back to them. The pump is letting the water backflow into the tank. There's no other reason for the water to get there. You will need to fix the pump or replace it. The pump should be under warranty so Scamp should fix it for free. Call them instead of trying to do something not needed.

[Raspy]

The check valve in the pump is not sealing. This could be because it is broken or because it has a piece of debris stuck in it.

First thing to do is shut off the shore water supply. Then open a faucet and turn on the trailer water pump for a short time. This may clear the problem. Then turn off the pump and turn on the shore water. If the tank stops filling, it's fixed.

If it still leaks, you could simply replace the pressure pump or take it apart and try to fix it.

Also, if the check valve is bad, the pump will cycle on and off occasionally if you are using it for pressure, even if you are not using water.

[C&G in FL]

This happens because the water from the city connection back flows through the 12v pump and fills the tank. The check valve in the pump which is only supposed to allow water flow in one direction is not sealing properly. The steps to hopefully unstick the check valve (some already stated by Raspy) are as follows:

1. Shut of city water supply
2. Turn on pump to pressurize system from fresh water tank
3. Turn off pump
4. Open faucet to relieve pressure
5. Open spigot to turn city water back on and observe overflow. If it stops overflowing, problem is "fixed."

Again, as already stated, if this doesn't work, you probably have a ShurFlo 12v pump. TURN OFF ALL WATER SOURCES and relieve pressure on the system. You can then remove the end cap (held on by 3 screws if I remember correctly) from the pump (the end where the hoses/tubes are connected) after first disconnecting the hoses. The check valve can be replaced or it may just have mineral deposits from contact with water. You can try soaking it in vinegar for a while and then gently wipe it clean and reinstall it. When you remove it, make a mental note of how it goes back together. While it may sound complicated, it really is quite intuitive/simple. If you can operate a screwdriver, you can do this repair.

You can also purchase an inline check wave from Amazon and put it between the pump and the outgoing tube and not worry about the pump's internal check valve. They, however, are also susceptible to getting stuck and might require servicing.

[Alf S.]

Originally Posted by CPW

This happens because the water from the city connection back flows through the 12v pump and fills the tank. The check valve in the pump which is only supposed to allow water flow in one direction is not sealing properly. The steps to hopefully unstick the check valve (some already stated by Raspy) are as follows:

1. Shut of city water supply
2. Turn on pump to pressurize system from fresh water tank
3. Turn off pump
4. Open faucet to relieve pressure
5. Open spigot to turn city water back on and observe overflow. If it stops overflowing, problem is "fixed."

Again, as already stated, if this doesn't work, you probably have a ShurFlo 12v pump. TURN OFF ALL WATER SOURCES and relieve pressure on the system. You can then remove the end cap (held on by 3 screws if I remember correctly) from the pump (the end where the hoses/tubes are connected) after first disconnecting the hoses. The check valve can be replaced or it may just have mineral deposits from contact with water. You can try soaking it in vinegar for a while and then gently wipe it clean and reinstall it. When you remove it, make a mental note of how it goes back together. While it may sound complicated, it really is quite intuitive/simple. If you can operate a screwdriver, you can do this repair.

You can also purchase an inline check wave from Amazon and put it between the pump and the outgoing tube and not worry about the pump's internal check valve. They, however, are also susceptible to getting stuck and might require servicing.

Hi: CPW... I used this procedure to reset the 12V pump. So far it has stopped back filling the fresh water tank. CG. water supplies are just more hard and gritty even with an in line filter.
Alf S. North shore of Lake Erie

[gordon2]

Question for my own elucidation which might also help the OP.....

With this type of failure of the check valve in the pump, will it work to fill the fresh water tank and use that with the pump instead of the city water connection? Or is there some reason the pump would not work properly?

BTW, I rarely use the city water connection.. too many potential problems with the constant pressure, including leaks on the hose ends, and too much trouble to go outside to turn the water on and off as needed. And using the onboard tank, I can track my water usage fairy close and know when the gray water tank is getting full.

[drmarylynn]

These responses are great. . .thanks for the input! As it happens I am on a National Parks tour and will be headed to North Dakota in a couple weeks. (I'm currently in the Rocky Mountains.) I called the Scamp folks in Backus, MN and will be taking it there on my way through. He said it's not an uncommon problem and they would be happy to take care of it. I really like those guys!

Thanks for the input from everyone, I'm saving these replies in case it happens again!

[Civilguy]

On our Casita trailer we have a Flojet 3526-144. It is a pretty common pump and I think(?) other RV pumps are built similarly.

Our pump failed last year the first time we took the trailer out after winter storage. When I turned it on, the pump would not pressurize water from the on-board fresh water tank so I quickly shut it off.

There is a one-way valve inside the pump called a check valve. If this valve is stuck open, the pump won't pressurize water from the on-board tank. This valve also prevents flow from the city-water side to the on-board tank.

It turns out that this internal valve can get stuck just because the pump hasn't been run for a long time. This is a very common problem and it can often be easily cured without disassembling the pump.

In my case I did not know this, so I took the pump apart and basically found nothing; no mineral buildup, no worn or broken parts, no nuthin'! However, the pump worked just fine after reassembly.

Based on having seen how the pump is built and the advice shared on a thread last December, I think the best approach is to 1) shut off and disconnect the campground water supply 2) and run the pump for up to a minute or so while sucking on the shower head hose. This should cause the pump to begin producing flow with no tools or disassembly required.

Here's a link to the thread I mentioned:

http://www.fiberglassrv.com/forums/f...ank-77885.html

Once the pump is able to produce pressure, it will then also prevent the city water from flowing to the on-board tank. I think it's worth a try.