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Topic: water entering fresh water tank? (Read 737 times) previous topic - next topic

water entering fresh water tank?

water seeping slowly  into my fresh water tank when hooked up to shore water.Every morning i have to drain some from tank due it draining  out overflow pipe.The only way i know this could happen is seeping by my fill valve but it appears to tightly close.Before i take floor out of cabinet to replace thought i would ask if there are other ways it could enter and if anyone else has same issues.1995 U300.

Thanks  Curley

Re: water entering fresh water tank?

Reply #1 –
Two most likely suspects are the fill valve and the check valve in the water pump.  Either could be leaking.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: water entering fresh water tank?

Reply #2 –
We avoid ever experiencing your problem by filling our water tank and then shutting off the shore water connection.  We believe it is a safer procedure to use the water out of the tank and shut off the water pump whenever not actively using water.

I know that's not the answer to your question, but it is a way to both circumvent your problem AND avoid potential floor flooding scenarios.  TIFWIW

1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: water entering fresh water tank?

Reply #3 –
Quote from: Chuck & Jeannie –
We avoid ever experiencing your problem by filling our water tank and then shutting off the shore water connection.  We believe it is a safer procedure to use the water out of the tank and shut off the water pump whenever not actively using water.
  TIFWIW

We do exactly the same.  That insures that water in the tank is always fresh and eliminates the potential for a broken hose or fitting to allow thousands of gallons of water to flood the coach.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: water entering fresh water tank?

Reply #4 –
If it was the pump check valve the pump would recycle. The valve replacement is simple if you use sharkbites. 15 minutes.
1994 U280, Build 4490
Deming, NM.

Re: water entering fresh water tank?

Reply #5 –
Quote from: Twig –
If it was the pump check valve the pump would recycle.

If still on shore water, it would not cycle (shore water PSI greater than water pump cut-in PSI.

But, as you say, if the check valve is leaking an no shore water, then, yes PSI would fall below pump cut-in PSI and pump would cycle on.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: water entering fresh water tank?

Reply #6 –
The valve that opens your tank should be at 90 degrees, perpendicular to the line. You can pull back the carpet to see the line and know where that is. My ball valve can actually exceed the 90 degrees, and this could lead to a small amount slipping by. You may want to check that you're 90 degrees perpendicular on that valve.
Jason
2000 U295 36' Non-slide  ISC350

Re: water entering fresh water tank?

Reply #7 –
Cycling the water pump a couple of times with a faucet open might clear it.
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: water entering fresh water tank?

Reply #8 –
Curley states that his fill valve appears to be "tightly closed" which sounds to me like he has the faucet washer type valve and not a ball gate valve. The faucet washer is rubber and tends to deteriorate over time and the slow leakage starts.
How do I know this? Had it happen to me until I replaced the faucet type with the gate ball valve.
Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD

Re: water entering fresh water tank?

Reply #9 –
Quote from: wolfe10 –
If still on shore water, it would not cycle (shore water PSI greater than water pump cut-in PSI.

But, as you say, if the check valve is leaking an no shore water, then, yes PSI would fall below pump cut-in PSI and pump would cycle on.

City water does not enter the tank through the pump. The tank will only fill through the fill valve.
1994 U280, Build 4490
Deming, NM.

Re: water entering fresh water tank?

Reply #10 –
Quote from: Twig –
City water does not enter the tank through the pump. The tank will only fill through the fill valve.

Yes, that is how it SHOULD BE.

But,. a defective check valve can allow water from the "pressure side" to leak back to the tank.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: water entering fresh water tank?

Reply #11 –
Quote from: Twig –
City water does not enter the tank through the pump. The tank will only fill through the fill valve.

On my coach water was reverse moving through the water pump and filling the tank (slowly) when connected to city water and with the waterpump off.  I could hear it and I could feel it.  And when I cleared it by cycling the pump it stopped.  Real world fact.

The water pump is connected to the fresh tank.  It can back fill the tank.  The check valve can hang up, or have debris in it.
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: water entering fresh water tank?

Reply #12 –
Quote from: AC7880 –
The check valve can hang up, or have debris in it.

Exactly.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: water entering fresh water tank?

Reply #13 –
Good point.
1994 U280, Build 4490
Deming, NM.

Re: water entering fresh water tank?

Reply #14 –
Quote from: Curley –
water seeping slowly  into my fresh water tank when hooked up to shore water.Every morning i have to drain some from tank due it draining  out overflow pipe.The only way i know this could happen is seeping by my fill valve but it appears to tightly close.Before i take floor out of cabinet to replace thought i would ask if there are other ways it could enter and if anyone else has same issues.1995 U300.

Thanks  Curley

it is a gate valve with lever.It has always operated properly and appears not to be moving past closed position.

Re: water entering fresh water tank?

Reply #15 –
Quote from: Curley –
it is a gate valve with lever.It has always operated properly and appears not to be moving past closed position.


No, a gate valve will have a round handle-- like any house hose spigot.

Ball valves have handles and are less likely to fail.

To test the water pump check valve:
Turn off/disconnect from shore water.
Turn on water pump.

If you hear it cycling, you either have a leak (water leaking somewhere) OR the check valve is allowing water to go back to the tank, which will lower pressure to below the cut-in pressure of the water pump and it will cycle.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020
 

Re: water entering fresh water tank?

Reply #16 –
Keep the city water shut off at the city faucet and use your tank water. Too much chance of a leak. If your tank is slowly filling and overflows, guess where the water is going? That could be an expensive leak. And then imagine if a connection failed in the coach and water flooded everywhere.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)