City water is filling fresh water tank

[LivinIt]

I’m currently at Fort Wilderness with a full house of kids and grandkids.
Last night, our first night I noticed water running out of the fresh water tank fill.

This is only the third trip with this unit, so a little miffed.

Did some Googling and the concencus seems to be bad/dirty check valve.
Anyone know where the pump on a 27RBDS is? I can hear it in the rear, but haven’t had time to explore yet.

My pressure is at approx 42, and I tried shutting off the water and running the pump for a bit. Selector valve was on city, still bleeding through.

. For now I guess I’ll just continue on pump for the remainder of the trip.

Why do they bother putting in a selector valve only to rely on a check valve?

 

[luvlabs-WO]

Not an uncommon problem. There are several points were failure can occur: The check valve in the water pump, the city water/tank fill valve, and, if you have one, the check valve between the water tank and the pump.

How to troubleshoot and fix:
1) With the water on, turn the tank fill/city water valve back and forth a few times. Sometimes a piece of debris gets in the valve and causes the problem.

2) The water pump is the next most likely candidate - make sure you shut off the pump when connected to city water. If that doesn't work, you can rebuild or replace the pump.

3) However, if you are not equipped with a check valve between the water pump inlet and the tank, locate that line and install a check valve in it. Even if the pump internal check valve leaks, it can't fill the tank since you have a second check valve preventing that.

 

[creativepart]

Don’t sweat it too much until it happens all the time. Turn off city water and turn on the pump and live off of the tank until it’s down to the level you usually keep it at. Then turn off the pump and resume using the city water. See if it happens again. It may, it may not. Be sure to not have the pump on when using city water. Your pressure regulator sounds right, I keep min at 50psi.

This has happened to me on two different RVs. Both times it only happened once or twice and wasn’t a constant issue.

 

[LivinIt]

Thanks for all the help guys, tried all the above and now waiting to see if it overflows again.

 

[LivinIt]

Well no luck, it’s still backfeeding and over flowing the tank. I’ll have to tear into it next weekend.
Thanks for all the help, I’m sure I’ll have more questions to come!

 

[old_engineer]

Have you tried turning off the winterizing valve between the tank and the pump as a bypass to the overfill until you can get the check valve repaired?


Edit: Also be sure the antifreeze hose valve is closed as well or else you might have a lot of extra water inside too.

 

[LivinIt]

Old Engineer I have not had time to do much of anything. We are back home and the trailer is in storage until I can look into this further.

The only valves I’m aware of so far are the tank and hot/cold drains below.
I’d love to install a manual valve that could eliminate the possibility of this issue occurring again. Is that possible?

 

[old_engineer]

I can't speak to your model but the Micro Minnie line of trailers have a valve between the pump and the tank that is turned off when winterizing the trailer with antifreeze. There is a second valve that goes to a short length of hose that is used to pump antifreeze from the bottle. Both valves are on a T close to the pump.


You should be able to add a valve if you can get access to the pump. You will have either a vinyl hose or PEX tubing that you can insert the valve into.

 

[Fasttimes]

On my first trip with the 27RBDS when I connected the city water no water was making it into the hot water heater. We ended up removing the wood panel that is louvered by the toilet and there was a valve that was closed. As others have said, this was closed for winterizing. Once I opened that up it's worked fine ever sense.

You might want to start there.

 

[LivinIt]

Yep, found the water pump wedged between the water heater and the back wall of the camper.
It is behind that louvered panel like yours Fasttimes.

I called Winn CS and they said they would email me a plumbing diagram right out. That was this afternoon, hope it comes.

 

[LivinIt]

I received the water line schematics from WB, but it’s not making any sense to me.
Ive read there is supposed to be a check valve between the pump and water supply to prevent water from backfeeding when on city water but I don’t see it on the schematic. I don’t see it in the camper either but it’s a cramped space with s lot going on in there.

The schematic does show a line from the docking station to the fresh water tank. What the heck is that for?? I could see if that was the line from pump to water tank, then there would be no need for a check valve. The schematic says “to” water tank. Again this makes no sense to me. I ran the pump with the valve on “city” and it still pressurized the system, so what is the purpose of the docking station valve?

Also the schematic shows a line from the black water flush inlet to “water inlet”. Again, what the heck is they?

 

[LivinIt]

Ok, well I see in the owners manual that the line from docking station to fresh water tank is so that you can fill the tank from the fresh water connection if you don’t want to use the gravity fill location.
That means I have two possible sources of back feed, the ball valve at the docking station or the diaphragm in the pump. Once I can get to a source of water this weekend I’ll find out.

 

[old_engineer]

I wonder if it is a problem with a control leaky valve? If it isn't fully shutting off the fresh water tank when in the city water position I could see it filling the tank.

 

[Mike Owens]

The check valve is normally on the pump. The discharge of the pump is connected to the city water line when the 3W valve is shut to the tank for filling. So it is either the 3W valve leaking or the check valve. Either will fill the tank. A way to determine if it is the check valve on the pump is to shut off city water and turn on the pump. If it cycles without using water the check valve is leaking. The strainer is from the tank suction. Look for debris in it as well. It is a maintenance item to clean the strainer / screen inside it.

 

[LivinIt]

My guess is the pump, based solely on the fact that it looks like a nightmare to get the pump out! Why do they do the things they do?
The pump does cycle when the city water is off and the pump is on. Every ten minutes or so it runs for a few seconds. I looked for a leak or faucet dripping but all looked good.
Is that what you meant cycles without using water?

This weekend I will isolate the problem. I will shut the valve between pump and water system and if it still overflows the tank I will clamp the fill hose that runs from the selector valve to the tank.

Thanks for the replies.

 

[LivinIt]

I picked up the camper from storage, hauled it to the house and hooked up the hose......no overflow. Maybe something was in the pump valve and got jiggled out?
Going on a short trip in two weeks, hope it’s still functioning properly.

 

[TonyOIB]

I had a thought last time I was packing up to leave camp. I had just hooked up my spare hose to rinse the black water tank and looked over at my fresh water connection where I noticed I had my water pressure regulator attached to my white hose, but never even thought of using one on my spare grey water hose! Everything I've read always tells you to use one on freshwater, but I wonder how many fellow RVers are like me and didn't even think about one for the black water flush?

 

[akeagle]

I'd say no pressure reduction is necessary on the spare hose since you're not pressurizing the MH's system, just rinsing the waste system.

 

[LivinIt]

Yeah, can’t see any need to regulate the spare hose.

 

[Donstar]

I'm pretty new to this but is there any problem with using your fresh water hose to connect to the black water tank flush connection when cleaning?