I must have a check valve issue, because when I attached city water to my trailer, I noted that it started (slowly) filling up my freshwater tank to the point it overflowed.I see that I can pretty easily replace the city water check valve, but I don't see where I can start looking for the other check valve - there must be one to prevent this from happening. Any ideas on where I should start looking? I have an APEX ULTRA-LITE - 249RBS.Thanks!Dan--Dan Simonson

The check valve is part of the water pump itself. Try running some water through your system by using the pump. That may reseat it or let whatever debris through that may be making it leak. If that doesn’t work, it’s fairly simple to take the pump head apart to clean and inspect the diaphragm.If you are referring to the city check valve at the hose connection that is not the issue. That one prevents pump pressure from pushing water out of that connection when it’s not In use,

wnjj wrote:The check valve is part of the water pump itself. Try running some water through your system by using the pump. That may reseat it or let whatever debris through that may be making it leak. If that doesn’t work, it’s fairly simple to take the pump head apart to clean and inspect the diaphragm.If you are referring to the city check valve at the hose connection that is not the issue. That one prevents pump pressure from pushing water out of that connection when it’s not In use,X2

Thanks - exactly the tip I needed. So I will check out the pump. I ran it several times trying to investigate this, also to empty some of the water out of my overflowing freshwater tank, so I'm thinking the pump is the issue and I'll take it apart. wnjj wrote:The check valve is part of the water pump itself. Try running some water through your system by using the pump. That may reseat it or let whatever debris through that may be making it leak. If that doesn’t work, it’s fairly simple to take the pump head apart to clean and inspect the diaphragm.If you are referring to the city check valve at the hose connection that is not the issue. That one prevents pump pressure from pushing water out of that connection when it’s not In use,

Just remove the INLET pipe to the Water Pump. Turn on City Water and you will see water come out of the Inlet of the pump if the Pump check valve is the problem. Doug

Good point, just got finished doing that. Result: no leak from inlet (fresh water tank to pump) side. Sigh... that would have been an easy fix! I am flummoxed as to how my freshwater tank could be filling up when the trailer is attached to city water! Perhaps a high water pressure issue, and my home water supply pressure is less than the park water pressure where this happened?dougrainer wrote:Just remove the INLET pipe to the Water Pump. Turn on City Water and you will see water come out of the Inlet of the pump if the Pump check valve is the problem. Doug

City Water is filling/overflowing my freshwater tank

wa8yxm
Explorer III
Jun 29, 2020
dieseltruckdriver wrote:
If your tank is full, just disconnect the water hook up and use your tank and pump. I never use a water hookup, even if it is available, except to fill my fresh tank.

Some years ago one of the campgrounds I stay at handed us a notice that the city was "Super Chlorinating" the water system. Even a year later it still tasted of bleach.

Well I remembered something from my freshwater fish tank days
(Fill a bucket, let it sit, then add it to the fish tank to get rid of teh bleach in the city water)

So inspration hit and I filled the 80 gallon on board.. And sure enough with out pressure in the line the bleach taste went away..

So now.. I keep doing that.

Serendipity benefit: (Means unexpected good thing) Since I full time with memberships, and since my wife died. I can go 3-5 weeks on 80 gallons of fresh.. Membership is 2 weeks in one week out of the membership park
So summers I use two memberships and back & forth. One has very good water the other has issues. I hook up when I get to the good park, Dump and fill Dump and re-fill before I leave 2 weeks later and at the park I"m in today.. I keep the hoses in the hose storage. Do not even hook up. Half the work

Winters it is one week 2 week I only hook up at the 2 week full hookup park .
dieseltruckdriv
Explorer II
Jun 29, 2020
If your tank is full, just disconnect the water hook up and use your tank and pump. I never use a water hookup, even if it is available, except to fill my fresh tank.
D_E_Bishop
Explorer
Jun 29, 2020
If you try all of the suggestions you have received but to no avail, I will offer that you do have a bad check valve. I am making an assumption that all your valves in the correct position. There is really no other possibility and I have experienced it in the past and I have seen at least one other RV that had the same problem.

Let us know what you find.
Mbiviano
Explorer
Jun 28, 2020
Turn city water off, then make sure you open all faucets hot and cold side and run water pump to get air completely out. Then shut off and open city water again. There’s some YouTube videos out there on it and worked for me recently when faced with same problem.
wa8yxm
Explorer III
Jun 28, 2020
On many RV's there is a 2nd path to fill the tank from city inlet. A "Quick Fill" (As Damon called it on mine) Valve. this is a common 3-way diverter valve
Turned one way it feeds water to the "Houe" the other way to the tank and half way in between both of 'em (Not supposed to do that) if it's not full stop then it may be letting water into the tank.
If the O-Rings in the valve have failed.. Likewise

Easy fix on most RV's.
Lynnmor
Explorer
Jun 28, 2020
You may have a fresh water fill valve that is used to fill the tank. That valve may be faulty or not turned completely off.
dsimonson
Explorer
Jun 28, 2020
Good point, just got finished doing that. Result: no leak from inlet (fresh water tank to pump) side. Sigh... that would have been an easy fix!

I am flummoxed as to how my freshwater tank could be filling up when the trailer is attached to city water! Perhaps a high water pressure issue, and my home water supply pressure is less than the park water pressure where this happened?

dougrainer wrote:
Just remove the INLET pipe to the Water Pump. Turn on City Water and you will see water come out of the Inlet of the pump if the Pump check valve is the problem. Doug
dougrainer
Nomad
Jun 28, 2020
Just remove the INLET pipe to the Water Pump. Turn on City Water and you will see water come out of the Inlet of the pump if the Pump check valve is the problem. Doug
dsimonson
Explorer
Jun 28, 2020
Thanks - exactly the tip I needed. So I will check out the pump. I ran it several times trying to investigate this, also to empty some of the water out of my overflowing freshwater tank, so I'm thinking the pump is the issue and I'll take it apart.

wnjj wrote:
The check valve is part of the water pump itself. Try running some water through your system by using the pump. That may reseat it or let whatever debris through that may be making it leak. If that doesn’t work, it’s fairly simple to take the pump head apart to clean and inspect the diaphragm.

If you are referring to the city check valve at the hose connection that is not the issue. That one prevents pump pressure from pushing water out of that connection when it’s not In use,
Mike134
Explorer
Jun 28, 2020
wnjj wrote:
The check valve is part of the water pump itself. Try running some water through your system by using the pump. That may reseat it or let whatever debris through that may be making it leak. If that doesn’t work, it’s fairly simple to take the pump head apart to clean and inspect the diaphragm.

If you are referring to the city check valve at the hose connection that is not the issue. That one prevents pump pressure from pushing water out of that connection when it’s not In use,

X2