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David & Diane 09-02-2019 08:03 PM

Possible Bad Check Valve or Inside Monitor
I have a steady water leak out of the "VENT" on the Anderson Valve Distribution Panel. The leak is only if the Anderson valve is in the "City Fill" position and only when the indoors fresh water tank fill monitor is over 65%.

DRV thinks its the Anderson Valve. I see no leaks on the rear of the valve assembly or the valve fittings. I think it might be the check valve or the inside the RV fresh water tank monitor lying about the fresh water tank level. I get a steady stream of water out of VENT when the monitor reads 88% or more and decreasing to no water out of VENT when the monitor is down to about 65% or less. Could I be unintentionally overfilling the fresh water tank because the inside tank level monitor is lying?

I get no water into the fresh water tank except when the valve is in the city fill position.

Does anyone know where I can find the check valve? Does anyone have any other ideas?

Big Willy 09-03-2019 12:47 PM

Isn't the purpose of the "City Fill" selection to fill your tank? Wouldn't that be why your tank is overflowing? For city water connection use "City Fixtures".

wingnut60 09-03-2019 04:22 PM

Certainly, your SeeLevel gauge could be off. But, after 2 years of using the FW tank regularly in our '15, I see water out the vent at various levels of gauge readings. It usually 'burps' water when filling to max. I also get water out the vent when traveling, if over the 85% level. Solved this by using a soft foam plug (ear plug will work) to prevent the sloshing while traveling--allows air to escape, but stops the water. Are you needing to use the tank regularly for dry-camping?

David & Diane 09-03-2019 07:24 PM

Reply: Possible Bad Check Valve or Inside Monitor
I seldom use the fresh water tank. I filled it this time because I was preparing to evacuate for hurricane Dorrian. Turned out, I didn't have to evacuate, but I was prepared. The leak, if it is a leak occurred with water flowing out the VENT when the inside monitor exceeded 70%. If the monitor exceeded 80%, the water flowing out of VENT was a strong steady stream. The valve is in the City Fill position.

If I left the city water on & moved the valve to Normal or City Fixture, the water out of VENT stopped. If I leave the valve in Normal or City Fixture with the city water turned on, I get no water flowing, even slowly into the fresh water tank.

DRV tech support thinks the problem is the Anderson Valve. I'm not sure. What do you think? Could the problem be the check valve? Do you know where the check valve is located?

MS60ocb 09-03-2019 09:11 PM


Originally Posted by Big Willy (Post 200986)
Isn't the purpose of the "City Fill" selection to fill your tank? Wouldn't that be why your tank is overflowing? For city water connection use "City Fixtures".

This all that needs to said. Are as far monitor level mine is off at least 15 gal on the low end. I can't tell about the high end a never wanted to pressurize my tank as you may be doing.
One other thing you may watch for and you may be doing it. Always remove the pressure on both sides the Anderson Valve before turning to a difference position.

Clay 2016 MS 38PS3

Porkchop 09-03-2019 09:51 PM

If your valve is set to "city fill" of course water will run out. The tank is over flowing. Simply shut the hose off! Where do you think the water should go when the tank is over full?
And the statements about plugging it to keep water from running out when moving are right on. It's no big deal. Water is just sloshing out the vent when moving until you lower the tank level. Just unplug it when using the pump to prevent a vacuum in the tank.


David & Diane 09-04-2019 02:51 PM

Possible Bad Check Valve or Inside Monitor
I had an additional discussion with a DRV tech support rep (Greg). His view was that my system is operating normally and that I do not have a problem. He explained that the Fresh Water tank requires some internal air to operate. Also, because of the position of the overflow on the fresh water tank, I can expect some water out of VENT whenever the fresh water level reaches approximately 70% or more.
A personal investigation of my system showed no water leakage out of the Anderson valve and no leakage from any of the fittings. I had water flowing from VENT only if the valve was in City Fill and only if the fill level in the fresh water tank reached 70% or more. I had a trickle at 70% increasing to a steady stream at an 85% fill level. I never went past 85% and immediately reduced the fill level when I saw the water flowing from VENT.
I believe I had incorrectly assumed a problem because I did not expect the fresh water tank to overflow at any level less that 100%.
I will be filling my Fresh Water tank to a maximum of 70% IAW the inside SeeLevel II Tank Monitor.
My conclusion is that my system is operating normally and that I do not have a problem.
The check valve I was looking for is apparently internal to the water pump and can only be accessed by disassembling the water pump.
Id appreciate anyone elses opinions and thoughts on this topic & on my conclusions.

Cummins12V98 09-04-2019 03:10 PM

The sensors are simply sensors. They may or may not be accurate!

wingnut60 09-05-2019 03:17 PM

Most of the water pumps do have an internal check valve. As Porkchop said--at 85% your tank is obviously full/near full, so gauge is off. Possibly you have a tank with the vent installed too low for 100%, or gauge is off....the use of a foam rubber plug (ear protector, or, I am using a foam dart out of a play gun) will allow air in/out, but stop most water movement.
You seem to be resigned to the situation, so just keep on keeping on....

David & Diane 09-05-2019 06:31 PM

Possible Bad Check Valve or Inside Monitor
DRV Tech Support seems to feel my inside monitor is spot on accurate. They feel that the VENT, Fresh Water Tank, overflow, etc are operating as designed and as they should. I don't really understand why a Fresh Water tank needs a bunch of internal air to operate properly, but DRV says that at least for my model & year it does. I was surprised that 70 to 85% full was considered as full as the tank should ever be. I guess I have to accept the system as it is if it is operating as designed.

Do you all disagree with DRV's assessment?

Porkchop 09-05-2019 08:24 PM

I don't disagree with their assessment. But I do disagree with their thinking the gauge is accurate. RV gauges are notorious for being wrong. I'll bet your tank is actually fuller than it indicates, but it really matters little. The tank does need to be vented to prevent a vacuum when the pump runs, but it certainly does not need that much. Good luck


David & Diane 09-05-2019 09:36 PM

Possible Bad Check Valve or Inside Monitor
Thanks for your reply. You are probably right that the tank holds more than the monitor reads. It matters little to me because if I fill the tank to the just the VENT dribbling point, it holds enough water for my wife & I for a week including the dish washer. I guess the most important point from this thread is that I do not have a problem.

Thanks again for the responses.

wingnut60 09-05-2019 11:05 PM

I dry-camp A LOT, and always want my fresh tank as near to full as possible, so fill best I can as near to the campsite as possible. Used to lose several gallons out vent on way to site after filling, no more since using a foam plug in vent. Agree that the tank needs way for air to get in/out, but apparently the vent fitting may be too low to get the tank to the 95-100% point. Have seen 94% on mine when level and take a lot of time to fill tank. Just the least bit off-level to off-door-side will have a big effect on how much you can get in.

Porthole 09-12-2019 01:17 PM

I’ve never seen more then 92% on my gauge.
I’ve never put more then 90 gallons in, measured with a garden hose flowmeter (2 different types).

Past experience suggests the vent line is not a continuous slope to the tank, may even have dips or loops. May not be vented at the top of the tank, rather on the side.

In the side would put the vent about 1” down from the top.

1” would account for the difference in fill versus rated volume.

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