Fresh tank won't stop filling

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.

jymbee

Well-known member
Joined
Feb 20, 2018
Posts
1,437
Location
Upstate NY
First trip after de-winterizing. Arrived a campsite and connected to site water to partially fill fresh water tank then switched the bypass to use site water. All went well until I saw that the fresh water tank had filled and was overflowing. Still had water inside from the site water so I tried flipping the bypass valve back/forth a few times thinking that somehow it was stuck, but no luck.

When the site water is turned ou, the water continues to go to both places-- fresh tank fill and coach water.

Any idea where to start looking?
 

Kirk

Well-known member
Joined
Oct 30, 2005
Posts
1,612
Location
Full-time , Escapee
The water pump also acts as a check valve to prevent water from backflowing into the tank. Try turning off the city water supply and then turn on the pump and use water from the tank for several gallons or so and allow the pump to shut off by pressure as it normally does. Once that has happened, try city water again but watch the tank. It may be that you will need to rebuild or replace the fresh water pump.
 

Rene T

Site Team
Joined
May 20, 2011
Posts
18,679
Location
Farmington NH
When you say bypass valve are you talking about the valves for bypassing the water heater? The hot water bypass valves valve have nothing to do with filling that tank. Do you have a tank fill valve that has to be positioned to normal operation? Maybe that’s the valve you’re referring to. If it is, it’s not a bypass valve per say. It’s either in the tank fill position or normal operation
 

JayArr

Well-known member
Joined
Jun 13, 2020
Posts
863
Location
Mission British Columbia Canada
I think he's talking about the valve in the pump itself Rene. There is a one way valve inside the pump body that holds pressure on the sensor that controls the pump, this is how the pump shots off and then automatically comes on when you open a tap, the pressure falls, the switch comes on and starts the pump. Without the one way valve in the pump body this system wouldn't work. If this valve leaks then city water pressure can push water into the fresh water tank - sort of an in through the out door situation.

I don't think it has anything to do with the valves for the hot water tank.
 

JudyJB

Well-known member
Joined
Jul 6, 2010
Posts
1,947
Had this happen more than once, and it meant I needed to replace the water pump. Even if it stops filling the water tank, keep checking it because it may start up again and you will have water overflowing.
 

garyb1st

Well-known member
Joined
Dec 31, 2010
Posts
4,101
Location
Southern California
Sounds like your handle is not actually moving the diverter valve. Ours failed in our 2005 Fleetwood Pace Arrow. The valve is fine but replacing the handle is a problem. I can move it from fill to bypass with a pliers. I've purchased a new valve but haven't put it on yet. In the meantime, we leave the valve on pass through and just fill the fresh tank via the gravity fill. Your Bounder is probably similar.
 

jymbee

Well-known member
Joined
Feb 20, 2018
Posts
1,437
Location
Upstate NY
The water pump also acts as a check valve to prevent water from backflowing into the tank. Try turning off the city water supply and then turn on the pump and use water from the tank for several gallons or so and allow the pump to shut off by pressure as it normally does. Once that has happened, try city water again but watch the tank. It may be that you will need to rebuild or replace the fresh water pump.
That makes sense. Actually we had shut off the park water and have been using the pump. When we get back to the coach I'll turn the water back and see if makes any difference.

Another detail is that I usually connect a water pressure control gizmo to the park water but we arrived late at this COE site and I put that off. Could too much water pressure coming in be a factor?
 

jymbee

Well-known member
Joined
Feb 20, 2018
Posts
1,437
Location
Upstate NY
When you say bypass valve are you talking about the valves for bypassing the water heater? The hot water bypass valves valve have nothing to do with filling that tank. Do you have a tank fill valve that has to be positioned to normal operation? Maybe that’s the valve you’re referring to. If it is, it’s not a bypass valve per say. It’s either in the tank fill position or normal operation
Nope, nothing to do with hot water valve. See attached:
 

Attachments

  • bypass.jpg
    bypass.jpg
    156.9 KB · Views: 21

jymbee

Well-known member
Joined
Feb 20, 2018
Posts
1,437
Location
Upstate NY
Had this happen more than once, and it meant I needed to replace the water pump. Even if it stops filling the water tank, keep checking it because it may start up again and you will have water overflowing.
Oh sure, the ol' glass half empty scenario! (kidding of course)

I have a feeling based on the input here that one way or the other the issue is with the pump which will ultimately need to be replaced. That's something we had anticipated looking into, replacing or rebuilding, shortly given it's age and low pressure.
 

Henry J Fate

Well-known member
Joined
Jun 14, 2018
Posts
1,701
If the back check valve on the pump is passing water to the fresh water tank, it is likely that an increase in pressure will affect it. Most likely is that if the pump back check valve is passing water with a city hook up, you should very possibly be noticing the pump cycling when no water taps are being used with no city water hook up. The interval of cycling will depend on the leak but if city water is pushing through, most likely pump pressure will be relieved to the tank in-between pump cycles as well.

Is there a separate filler tube to fill the fresh water tank or is it valved from the city water connection ?
 
Last edited:

JayArr

Well-known member
Joined
Jun 13, 2020
Posts
863
Location
Mission British Columbia Canada
I have a feeling based on the input here that one way or the other the issue is with the pump which will ultimately need to be replaced.

Be aware that you may be able to buy just the pump portion - without the electric motor.

It doesn't sound like there is anything wrong with your motor so this will save a bunch of $$. The pump part will unbolt from the electric motor by removing two or three screws and the new pump just bolts on. It's easy and requires no additional special tools. Youtube should be your friend for details on how to change it.
 

NY_Dutch

Well-known member
Joined
Nov 22, 2010
Posts
7,308
Location
Where our wheels take us!
If the pump is otherwise working ok, another fix is to pick up an inline check valve at the nearest big box, Ace, or other hardware vendor. It can be installed on either side of the pump, just pay attention to the directional arrow. I carry a 1/2" check valve from Watts Aqualock that can be installed in PEX piping with just a sharp knife in my spares. Sharkbite and others make similar fittings. Eventually the pump should be repaired or replaced of course, but a push on inline check valve can be a quick fix and trip saver.

 

Kirk

Well-known member
Joined
Oct 30, 2005
Posts
1,612
Location
Full-time , Escapee
Could too much water pressure coming in be a factor?
It is possible, but not probable. While adding a check valve next to the pump would be a quick fix and cost less, a pump that is leaking back is already having problems so would likely fail soon anyway. With yours now 9 years old, if used a lot it could be nearing time to replace or rebuild it. I would rebuild, unless you were thinking of upgrading the pump anyway if yours has a rebuild kit available. And I would also consider just replacing the pump on the existing motor. If you change the pump, you may want to consider adding an accumulator in the pump discharge as well.
 

jymbee

Well-known member
Joined
Feb 20, 2018
Posts
1,437
Location
Upstate NY
It is possible, but not probable. While adding a check valve next to the pump would be a quick fix and cost less, a pump that is leaking back is already having problems so would likely fail soon anyway. With yours now 9 years old, if used a lot it could be nearing time to replace or rebuild it. I would rebuild, unless you were thinking of upgrading the pump anyway if yours has a rebuild kit available. And I would also consider just replacing the pump on the existing motor. If you change the pump, you may want to consider adding an accumulator in the pump discharge as well.
Ok, here's the update:
DId turn off the park water and used the coach water pump to do some dishes, take a shower, etc. Then installed the pressure control valve (Renator Water Pressure Regulator Valve), turned off the pump and turned on the park water. Wait for it... wait... wait... well ok, looks like no leaks. Hours later still dry.

I guess it can't be know exactly what the problem or cure was, but for now at least I'm relieved to back to normal. We have a scheduled visit in a few weeks with an RV Repair guy who has done a lot of stuff for us in Jackson, MS, On that "to do" list was looking at upgrading our current water pump. Looks like good timing.

Many thanks to all the helpful suggestions!
 

jymbee

Well-known member
Joined
Feb 20, 2018
Posts
1,437
Location
Upstate NY
If the pump is otherwise working ok, another fix is to pick up an inline check valve at the nearest big box, Ace, or other hardware vendor. It can be installed on either side of the pump,
On my shopping list. Thanks!
 

jymbee

Well-known member
Joined
Feb 20, 2018
Posts
1,437
Location
Upstate NY
Sounds like your handle is not actually moving the diverter valve.
That remains a possibility and one that a new pump wouldn't cure. But I did work that valve back and forth and it seemed, from the outside at least, to engage and be working.
 

Kirk

Well-known member
Joined
Oct 30, 2005
Posts
1,612
Location
Full-time , Escapee
That remains a possibility and one that a new pump wouldn't cure.
That is very highly improbable since if it failed to change you would fill the tank but not supply water to the system as that is a 2 position diverter valve. There would be no water without the pump running if that valve stayed in the tank fill position.
 

jymbee

Well-known member
Joined
Feb 20, 2018
Posts
1,437
Location
Upstate NY
That is very highly improbable since if it failed to change you would fill the tank but not supply water to the system as that is a 2 position diverter valve. There would be no water without the pump running if that valve stayed in the tank fill position.
But course-- uh... I knew that! Or to be more truthful, I'd like to think I would have eventually figured that out. ;)
 
Top Bottom