Fresh water tank filled itself!

toolman.dustin

Senior Member
RV LIFE Pro
Joined
Apr 30, 2019
Messages
137
Location
Kansas
Last week I spent one night at an RV park. The fresh water tank was empty. I connected to city water. I use an adjustable regulator so I know the water pressure was 45 psi. The next morning the fresh water tank was heavily dripping water out of the overflow. I turned on the bathroom and kitchen faucets and drained the 45 gallon fresh water tank.

I can only presume the fresh water pump somehow allowed water to back fill the fresh water tank from the city water inlet. Imagine if it hadn't overflown I would have never know. Not only would I have been hauling 360 lbs of water I would imagine that much weight in the tank could cause the tank to break loose while driving.

The only thing I can think to do is replace the diaphragm in the pump. It only happened the one time but I'm not sure I can trust it to not happen again.

Anyone ever seen this problem?

Dustin
 
Not sure how your water valves are setup (which system you have installed), but it could be an early indicator that one of your valves is failing.

Sent from my SM-G950U using Tapatalk
 
Last week I spent one night at an RV park. The fresh water tank was empty. I connected to city water. I use an adjustable regulator so I know the water pressure was 45 psi. The next morning the fresh water tank was heavily dripping water out of the overflow. I turned on the bathroom and kitchen faucets and drained the 45 gallon fresh water tank.

I can only presume the fresh water pump somehow allowed water to back fill the fresh water tank from the city water inlet. Imagine if it hadn't overflown I would have never know. Not only would I have been hauling 360 lbs of water I would imagine that much weight in the tank could cause the tank to break loose while driving.

The only thing I can think to do is replace the diaphragm in the pump. It only happened the one time but I'm not sure I can trust it to not happen again.

Anyone ever seen this problem?

Dustin

Doubt your Pump is the issue and I would hope full tanks are designed to not fall off the trailer

My first thought would be the switch valve in the wet bay


2021 Imagine 2400 BH
2018 GMC Sierra 4x4 crew
 
Last week I spent one night at an RV park. The fresh water tank was empty. I connected to city water. I use an adjustable regulator so I know the water pressure was 45 psi. The next morning the fresh water tank was heavily dripping water out of the overflow. I turned on the bathroom and kitchen faucets and drained the 45 gallon fresh water tank.

I can only presume the fresh water pump somehow allowed water to back fill the fresh water tank from the city water inlet. Imagine if it hadn't overflown I would have never know. Not only would I have been hauling 360 lbs of water I would imagine that much weight in the tank could cause the tank to break loose while driving.

The only thing I can think to do is replace the diaphragm in the pump. It only happened the one time but I'm not sure I can trust it to not happen again.

Anyone ever seen this problem?

Dustin

I'm assuming the adjustment knob was still set to "city water?" 2600.JPG
 
Last week I spent one night at an RV park. The fresh water tank was empty. I connected to city water. I use an adjustable regulator so I know the water pressure was 45 psi. The next morning the fresh water tank was heavily dripping water out of the overflow. I turned on the bathroom and kitchen faucets and drained the 45 gallon fresh water tank.

I can only presume the fresh water pump somehow allowed water to back fill the fresh water tank from the city water inlet. Imagine if it hadn't overflown I would have never know. Not only would I have been hauling 360 lbs of water I would imagine that much weight in the tank could cause the tank to break loose while driving.

The only thing I can think to do is replace the diaphragm in the pump. It only happened the one time but I'm not sure I can trust it to not happen again.

Anyone ever seen this problem?

Dustin

Provided your selector lever was set to city water it may be a bad check valve after the water pump. There is a check valve to prevent city water from flowing into the tank.

I have seen other posts that said the valve on the panel was faulty. I think it would have to be one of those two valves.
 
Had same issue, it turned out to be valve inside pump housing. You may be able to increase pressure via allen head screw adjustment from outside black plastic pump housing or order new pump housing assembly from Amazon as I did. Get your model number of pump and Goggle manual or parts list for your pump.

More than liking it is check valve inside pump housing as it was on mine unless you were using city water fill valve and it could be this valve. I never use this valve due to reading about problems people have had with it on forum; just fill tank with hose from fresh water fill port on outside.
 
Here's a test: Disconnect the inlet piping to the pump. Now pressurize the system with city water. If water comes out of the pump inlet the pump check valve is bad. If no water comes out but the tank still fills it's the City-Fill valve. Sometimes you can re-seat the "O" rings in the valve by depressurizing both sides of the system and moving the selector lever back and forth a few times.

Since I have a gravity port on my Imagine, if the City-Fill valve leaks I'll just bypass it.
 
Buckskin - This seems to be the case with mine. I don't have a pump/city water valve. The outlet on the pump is "Teed" into the fresh water line that feeds the trailer. The fresh water tank is only filled with a hose from the outside. No valves. I always use an inline water filter and pressure is set to 45 psi. I'll get the pump part number, and an exploded view diagram. The answer is either, pump bad internal check valve, leaking diaphragm or debris that entered the system "somehow". However, since I'm going to have to take things apart, I think I will add a selector lever that allows me to fill the fresh water tank via the city water inlet.
 
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