Water Back-flow Into The Fresh Water Tank

[dmjaway]

I have a 2017 Forest River Sunseeker 3050S Class 'C' Motor home and am experiencing a problem where, at certain times, the water pump is allowing RV park water to flow back through the WP's check-valve into the fresh water tank.

I have changed out the water pump but still have the same problem.

Is there anyone experiencing this problem?

[Dutch_12078]

wnjj wrote:

dmjaway wrote:
As far as I know, there is only one way into the Fresh Water Tank, (via the external fill port) and only one way out of the Fresh Water Tank, (via the water pump, first passing through the WP filter).

There is also a vent, though it’s not likely to be a source of water.

A city water tank fill setup is often just a valve controlled bypass around the pump that uses the tank outlet as an inlet.

[wnjj]

dmjaway wrote:
As far as I know, there is only one way into the Fresh Water Tank, (via the external fill port) and only one way out of the Fresh Water Tank, (via the water pump, first passing through the WP filter).

There is also a vent, though it’s not likely to be a source of water.

[dmjaway]

dougrainer wrote:
All you have to do, is remove the NON pressure input fitting on the pump from the water tank. With City Water connected, you will know if the pump is the problem. Water will flow out of the disconnected threaded fitting on the pump. Doug

Yes, that would be a good check if the problem was consistent, however, it is not a continuous problem and besides, with the FR SS 3050S it is no small chore.

[dougrainer]

All you have to do, is remove the NON pressure input fitting on the pump from the water tank. With City Water connected, you will know if the pump is the problem. Water will flow out of the disconnected threaded fitting on the pump. Doug

[dmjaway]

jolooote wrote:
You replaced the pump and still have the problem! Pump is NOT the problem. What is the water line Preasure? Can be simply too much preasure.

Only 40#s

[jolooote]

You replaced the pump and still have the problem! Pump is NOT the problem. What is the water line Preasure? Can be simply too much preasure.

[dmjaway]

dougrainer wrote:
You have had 2 bad pumps. VERY unusual. Are you POSITIVE the water is flowing thru the Water Pump? Doug

As far as I know, there is only one way into the Fresh Water Tank, (via the external fill port) and only one way out of the Fresh Water Tank, (via the water pump, first passing through the WP filter).

I am not sure if the water passes through the check valve prior to the internal WP pump housing, or after the internal pump housing?

The water would then flow through the Main filter Assy into the system.

[dougrainer]

You have had 2 bad pumps. VERY unusual. Are you POSITIVE the water is flowing thru the Water Pump? Doug

[dmjaway]

dougrainer wrote:
Since you have a FR brand. State what brand Water Pump you have. FR is known for installing the cheapest off brand or knock off brand parts in their RV's. Since you have replaced the pump, that should rule out the pump check valve, but if NOT a name brand(Shurflo or Flow Jet), then I would suspect the brand water pump is failing at its check valve. Now, if you have a valve that allows you to pressure fill the Fresh Tank when on city water, then THAT valve would be suspect also. Doug

The WP is a Shurflo 4008-101-A65

[dougrainer]

Since you have a FR brand. State what brand Water Pump you have. FR is known for installing the cheapest off brand or knock off brand parts in their RV's. Since you have replaced the pump, that should rule out the pump check valve, but if NOT a name brand(Shurflo or Flow Jet), then I would suspect the brand water pump is failing at its check valve. Now, if you have a valve that allows you to pressure fill the Fresh Tank when on city water, then THAT valve would be suspect also. Doug

[dmjaway]

mobeewan wrote:
Some times there are pieces of plastic that wind up inside the fresh water tank when they drill the holes for the tank fittings. You might also get dirt running down the sides of the trailer that washes into the tank filler hose if you have a tank fill opening that doesn't have a cap but relies only on a hatch that flips up and down to cover the opening.

You should have a strainer on the inlet side if the pump. It will have a fine stainless steel mesh screen. It catches any dirt, trash or particals from the fresh water tank that can cause problems with the pump or faucets. If you don't have one you should install one.

Shulflo RV pump strainers

I changed out the fill opening on my trailer to one with a cap behind a locking door. I did it for 2 reasons. First because I had dirt residue in the fill hose and second because when I had a dealer inspect and reseal the roof corners I also had them wash and wax the trailer. They used a spray on wax. Not only did I have dirt in the fill tube, I wound up with a pinkish colored wax inside the fill tube and probably inside the tank.

Thanks for the information.

The water pump in the FR Sunseeker 3050S is in an outside compartment and you have to remove all the plastic panels to get to is, so it is no easy job to clean or replace the WP filter, (need warmer weather).

I will look into covering the fill spout for the fresh water tank.

[mobeewan]

Some times there are pieces of plastic that wind up inside the fresh water tank when they drill the holes for the tank fittings. You might also get dirt running down the sides of the trailer that washes into the tank filler hose if you have a tank fill opening that doesn't have a cap but relies only on a hatch that flips up and down to cover the opening.

You should have a strainer on the inlet side if the pump. It will have a fine stainless steel mesh screen. It catches any dirt, trash or particals from the fresh water tank that can cause problems with the pump or faucets. If you don't have one you should install one.

Shulflo RV pump strainers

I changed out the fill opening on my trailer to one with a cap behind a locking door. I did it for 2 reasons. First because I had dirt residue in the fill hose and second because when I had a dealer inspect and reseal the roof corners I also had them wash and wax the trailer. They used a spray on wax. Not only did I have dirt in the fill tube, I wound up with a pinkish colored wax inside the fill tube and probably inside the tank.

[dmjaway]

Old-Biscuit wrote:
How do you normally fill fresh water tank?
Gravity fill port where you stick a hose in
OR
Via swapping a valve/switch to "FILL"

"FILL" valve...could be leaking thru

Water pump has an internal 'check valve' (diaphragm) that can not fully close due to construction debris or even scaling from water

When fresh water tank fills......turn off city water suppy...tuen pump ON and use the water in fresh water tank.
Using the pump water flows the correct direction thru pump and can clear up/clean the 'check valve' so it closes.

Fact is....only use the pump/fresh water tank---just fill fresh water tank as needed.

I fill from an outside port with a hose.

So, even though I have an internal water filter, (which is ahead of the pump), it would be a good idea to have a filter in the incoming water line to filter out the particulate from the RV Park water?

[Farmboy666]

There was just a long posting about this same problem. If you put a new pump in and it’s still doing it sounds like it’s not the pump. Check other valves.