Fresh water tank slowly filling on it's own

[Roger Rempe]

Recently, my fresh water tank has been slowly filling on it's own. I'm thinking that I may have a faulty Manobloc valve on the tank fill? Or, perhaps it could be something else? It's always been persnickety about getting it closed just right. I'm assuming that I'll have to remove the entire water station panel to get at it. Does anyone have experience doing this and tips on what to expect trying to replace the valve stem and dealing with that panel? Also, are all the valves stems "one size fits all"?

[Bryan Beamon]

Roger we replaced our water fill valve on our 07 Contessa in order to fix the same symptoms you have but found out it required a check valve inserted before the water pump in order to stop our fresh water tank from slowly  filling.

[Bob Jae]

It could be the check valve in your water pump.  Take a look at this troubleshooting video.  https://www.youtube.com/watch?v=p-zxHmcYiOE

[Roger Rempe]

Are we talking about the check valve just after the water hose hook up?

[Bob Jae]

No the valves in the water pump can leak and allow water back into the fresh water tank.

[Roger Rempe]

Thanks for the info on the check valves. I'll check those out first!

[Keith Moffett]

Roger
Though our type of valves differ, the idea is the same.  We just replaced the fill valve in ours and it is still doing what you describe.  Next we replace the water pump for the internal check valve.
Does your water pump surge just a little when all faucetts are off?  I think the check valve in the water pump allows a little water by when on city water and when on just internal water the pump  looses the prime just a bit. 
This lets some water by and into the tank.

[Roger Rempe]

Currently, we're strictly using the water pump since my original post and I have not noticed the occasional pump surge. That makes me wonder if it is the Manobloc valve on the tank fill after all?

[Roger Rempe]

Well, I replaced the water pump and using a water pressure restrictor at the the hook up. So far, so good...thanks all for the good help!