Fresh water tank fills itself...what to do?

[Papicamper]

I have a 2014 FR MicroLite, 21' TT. The fresh water tank seems to siphon water from the regular (city) inlet and fills itself up...then continues to overflow (at the FW inlet and city inlet) unless the water is shut off at the source. Very annoying! Is there some check valve or similar device that may be allowing city water connection to fill the fresh water tank? I have drained the FW Tank by running the faucet through an open gray tank but as soon as I put things back to normal it fills again. Pump functions normally when on (on demand). Any ideas where I should apply the hammer? LOL. Thanks for hints.

[chaps2018]

Common issue. The key thing is to relieve the pressure before switching to pump. Here is a fix that was posted here before and worked for me.

-Open any faucet to drop pressure to zero (no water flow)
-Turn on water pump
allow water to flow for a minute or so then shut off open faucet
-Once the pump stops, turn off water pump
-Turn city water back on.

This will reseat the back flow valve and 90% of the time corrects the problem. Once corrected, drain the FW tank unless you plan to use it.

-Alternate Turnoff the city water, with the pump off open a faucet to relieve pressure, then close the faucet and and open the city water valve. The city water pressure can seat the check valve better with no pressure behind it.

[katkt]

Originally Posted by Papicamper

I have a 2014 FR MicroLite, 21' TT. The fresh water tank seems to siphon water from the regular (city) inlet and fills itself up...then continues to overflow (at the FW inlet and city inlet) unless the water is shut off at the source. Very annoying! Is there some check valve or similar device that may be allowing city water connection to fill the fresh water tank? I have drained the FW Tank by running the faucet through an open gray tank but as soon as I put things back to normal it fills again. Pump functions normally when on (on demand). Any ideas where I should apply the hammer? LOL. Thanks for hints.

My V-lite, of about the same build time calender wise, did the same thing. There was a valve of some sort on the 12volt pump, that was supposed to prevent a backflow from the system, when the system was hooked to city water. That valve was bad.
The result was the same as you described. I'd hook to city water, and it would fill my fresh water tank.
The dealer I used, replaced the pump under warranty for me, and that was the end of it.



Edit....If it happens again, I'll try chaps2018 suggestion.

[rockfordroo]

papicamper:

Here's a generic RV plumbing pic that may help you.

[Duckogram]

Originally Posted by chaps2018

Common issue. The key thing is to relieve the pressure before switching to pump. Here is a fix that was posted here before and worked for me.

-Open any faucet to drop pressure to zero (no water flow)
-Turn on water pump
allow water to flow for a minute or so then shut off open faucet
-Once the pump stops, turn off water pump
-Turn city water back on.

This will reseat the back flow valve and 90% of the time corrects the problem. Once corrected, drain the FW tank unless you plan to use it.

-Alternate Turnoff the city water, with the pump off open a faucet to relieve pressure, then close the faucet and and open the city water valve. The city water pressure can seat the check valve better with no pressure behind it.

X2 - and if you have a bad check valve there is a repair kit you can easily get and install for about $10.

[Larry-NC]

I've added the one step that chaps forgot.

Larry

Originally Posted by chaps2018

Common issue. The key thing is to relieve the pressure before switching to pump. Here is a fix that was posted here before and worked for me.

-Turn off the city water
-Open any faucet to drop pressure to zero (no water flow)
-Turn on water pump
allow water to flow for a minute or so then shut off open faucet
-Once the pump stops, turn off water pump
-Turn city water back on.

This will reseat the back flow valve and 90% of the time corrects the problem. Once corrected, drain the FW tank unless you plan to use it.

-Alternate Turnoff the city water, with the pump off open a faucet to relieve pressure, then close the faucet and and open the city water valve. The city water pressure can seat the check valve better with no pressure behind it.

[Goat Man]

Had that happen to ours. For couple of years I would just let it fill, shut it off, then use the pump until water tank was empty and start over. The pump is hard to get to on mine, so I placed and external check valve on the line. It doesn't fill anymore.

[DrLewie]

Same thing happened to me a couple of months ago. The check valve in the water pump was faulty, so even with the pump turned off water diverted to the fresh tank. The check valve can't be replaced. I replaced the pump. Problem solved.

[Papicamper]

Thanks to all for info. I tried Chaps fix a couple times (and yes, I did turn off the CW first...LOL) but no dice.
Duck: You mentioned a repair kit...can you give me the source?

What I will probably do (if a repair kit isn't readily available) is install a shut off on the FW tank to prevent water input unless I want some. We rarely use FW source.
I appreciate all replies and hope for a kit source. THANKS!
gurgle...gurgle...gurgle...dammit...

[Duckogram]

Which model pump do you have? There are some that are not repairable. That said, if you get a speck of debris on the seat of the check valve it will leak. But before I break out the tools, I try the method above with a slight difference. I do not turn off city water. I disconnect it completely. Then I drain pressure in the system. Next I turn the pump on. After it shuts off I turn it off, drain pressure, turn it on, pressurize, run water to cycle the pump, then pump off and reconnect city water. If that does not clear the obstruction, it’s time to get the tools. Then I will remove the valve and clean the surfaces with a soft cloth. The rubber gets a “massage” with food grade silicone. Reassemble and test. I have done this to two pumps and it has worked both times. Cost was $0. Just my time.

Edit: This is a link for the kit that fits my current pump Shurflo - Check Valve (4008) - 94-800-03 - Explosive Powersports

[Papicamper]

[QUOTE=Duckogram;1881334]Which model pump do you have? There are some that are not repairable.

Thanks Duck. I have a Shurflo pump (works fine). Since we're on the road for another two months I'm going to do the shut off valve thing (very easy access)) on the pump output side that will prevent any seepage via the backflow/checkvalve in the pump to go anywhere. If we need FW I can fill via the FW port (as I should anyway).
I'm going to look over your attachment though and will probably do the cleaning, etc., after returning home...where it is easier. This thing is not Earth shattering...just annoying. I'm betting on debris in the checkvalve because when it's filling the FW tank it takes 2 or 3 hours from empty to do so...but then just keeps on "filling" causing dripping at the CW input and the FW input cap.
Thanks again!!!
Bill

[Duckogram]

Sounds good. As I recall, your pump is behind the docking station covered bt a plastic shroud. Easy to get at. We are also on the road, currently in MI.

[Papicamper]

Originally Posted by Duckogram

Sounds good. As I recall, your pump is behind the docking station covered bt a plastic shroud. Easy to get at. We are also on the road, currently in MI.

Thanks. The pump is just inside a front cubbie door (street side)...on the left side behind a sliding cover. Real easy to get at. I think I may need the triangular assy (not the square one) but will know when I remove the pump, etc.
We're in NE Utah right now...continuing on a 3 or 4 month Odyssey - LOL. Got a few more thousand to go...Have safe travels yourself!

[Duckogram]

Ahh, its been redesigned. Thats a good thing. We will be in UT the end of Sept. On our way home from Portlandia.
Shiny side up!