Question City Water Connection Leaking Into Fresh Water Tank(?)

[Altazi]

The first picture showing the water pump shows a white handled valve. Does this valve control switching from city water direct to filling the fresh water tank? If it is, then I suspect that is where your problem lies. I'm betting the valve does not close properly thus allowing your tank to slowly fill. This will also cause your water pump to cycle simply because the isn't always enough presure to activate the switch that shuts it down. Yours looks like it would be easy to replace. It is best to remove the valve to take it to your RV Dealer as a sample. There are many variations to that valve.

Good luck

Darrell

Hello Darrell,

That valve switches to the open-ended hose, possibly for flushing (?) See the picture further up when I initially posted. Nothing flows out of the open-ended hose when the valve is closed.

 

[Rollin Ollen]

Hello Darrell,

That valve switches to the open-ended hose, possibly for flushing (?) See the picture further up when I initially posted. Nothing flows out of the open-ended hose when the valve is closed.

Okay. That valve is probably used for winterizing your unit. It will probably suck antifreeze then. Your problem still sounds like the valve that allows you to fill your fresh water tank is malfunctioning? I am not familiar with your RV but I had the exact same problem with my Winnebago. Does your fresh water tank have a separate fill port or does your city water and fresh water fill share the same port?

Darrell

 

[Altazi]

Okay. That valve is probably used for winterizing your unit. It will probably suck antifreeze then. Your problem still sounds like the valve that allows you to fill your fresh water tank is malfunctioning? I am not familiar with your RV but I had the exact same problem with my Winnebago. Does your fresh water tank have a separate fill port or does your city water and fresh water fill share the same port?

Darrell

Hi Darrell,

There are separate ports for city water and fresh water tank fill. The fresh water tank fill port is very close to where the water pump is located, just inside the pass-through storage area at the front end of the trailer. The city water port is nearer the rear of the trailer, and the bathroom sink cabinet is on the rear wall of the trailer.

I wish I could find an exact diagram of the plumbing, showing what's what and where everything is located. This is killing me. I don't even know what a check valve looks like.

 

[Rollin Ollen]

Hi Darrell,

There are separate ports for city water and fresh water tank fill. The fresh water tank fill port is very close to where the water pump is located, just inside the pass-through storage area at the front end of the trailer. The city water port is nearer the rear of the trailer, and the bathroom sink cabinet is on the rear wall of the trailer.

I wish I could find an exact diagram of the plumbing, showing what's what and where everything is located. This is killing me. I don't even know what a check valve looks like.

I feel for you. Sorry I can't be more helpful. I am lost because you have separate filling ports so there shouldn't be any connection. The check valve issue seems to be your last resort and I'm not familiar with them.

 

[AbdRahim]

If the only way to fill the fresh water tank is manually and not through a valve to switch between city and fresh water tank, the the issue could be the check valve in the water pump itself. Did you try the procedure I suggested above?

 

[osuallen]

These two issues have not been corrected yet, and I am getting desperate.

1. The fresh water tank fills slowly when the trailer is connected to city water.

2. When using only the fresh water tank, the water pump continuously cycles every few seconds.

I know there have to be some sort of check valves in the system to prevent these problems, but I don't know where they are, or what they look like.

Here are a couple of pictures of the only (somewhat) accessible plumbing components. Aside from the water pump itself, I have no idea what any of this stuff is, or if it could be the cause of my problems.

PLEASE HELP!
View attachment 25929

Second picture - middle photo -- That is an air admittance valve. It is the plumbing "vent" for the lavatory.

 

[Kevin D Pem]

If the only way to fill the fresh water tank is manually and not through a valve to switch between city and fresh water tank, the the issue could be the check valve in the water pump itself. Did you try the procedure I suggested above?

Another rant! The inlet valve in the pump must act like a check valve, but it's not! RV MANUFACTURERS use it as such, and that's why there are so many problems with RVwater systems.

You may have noticed the strainer on the input! This device is required to warranty out the pump, that is because the pump manufacturer knows what they sell!

After quite a few pump replacements, I do the following:

1) put a check valve between the tank and the pump ( standard plumbing variety)
2) when that cheesy pressure switch fails, replace with a well pressure switch.

Nothing in an RV is made for real life trouble free use. I live full-time in my RV and would rather find room for quality, rather than constantly replace garbage!

Conclusion! Yes your problem is the lack of a check valve. If you're always on grid than just keep the tank drain open till you put a check valve in!!! Or put a inline valve to separate the pump from the system when not using it.

 

[Altazi]

I found manufacturer documents for the SHURflo 4008-101-A65 water pump used in my 220RBS. One shows an exploded diagram for the pump, with descriptions. Here is the legend from that drawing.

The one thing I wanted to see was the check valve - which is indicated as 'N/S', or 'Not Shown' on the drawing. FFS. After even more searching on the Internet, I found some helpful videos. I FINALLY found what I needed to know.

The check valve is part of the water pump.

NO ONE told me this. Maybe this is just one of those things that 'everyone knows'. Well, I didn't. I tore my trailer apart looking for what I thought was a separate check valve.

I removed the water pump and disassembled it.

What a pain in the arse. THIS is the check valve.

I took it apart - both O-rings seemed smooth and clean, the valve seat appeared clean and undamaged, but it doesn't seal well. I sucked on the outlet port and could easily pull air through the valve - as it should be. I blew into the outlet port and, while I met substantial resistance, air was leaking through the valve. If I held the valve assembly so the outlet port was vertical, just putting water into the port would show a dribble of water coming out of the valve.

Is this normal? Does the pump need more pressure to cause the valve to seal against backflow?

I checked on Amazon and found repair parts for the valve. There are 18% one-star reviews, with people saying it doesn't fit older pumps (mine was build in 2017). I could order an entirely new pump for around $100, or a new upper cover for around $42, but I would like to know why my check valve is leaking when the parts all appear to be okay.

I welcome any and all comments and suggestions on this. Thanks for your help so far.

A.