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Old 12-29-2018, 08:49 PM   #1
Brand: Thor Motor Coach
Model: Hurricane 34E
State: Florida
Posts: 46
THOR #11425
Tank overflow / valve problem?

Hey all, need an opinion... 2014 Thor Hurricane. Status panel shows the fresh water tank is full even though i don't recall filling it.

We're connected to city water and the four position rotating knob is set to "City Fixtures". When I look under the coach, there's a blue tube (presumably a drip tube)- hanging straight down right next to the fresh water tank. It's dripping water pretty steadily. It stops dripping when I turn the fill knob on the coach to "Normal" and turn the city water valve off at the post in my campground spot.

I'm presuming the fresh water tank is full to overflowing. I'm in the process of lowering the level of the water in the fresh water tank by turning the faucet off at the post, turning the knob on the coach to Normal and running the water pump.

Possibly related issue... for the past several weeks, when the water pump is on, I can hear it cycling on for about 2-3 seconds and then off for about 10 seconds. This is even when there's no open faucets in the coach. We're traveling in the Florida Keys so I'm hoping I don't have to have it looked at now.

Anybody have any ideas?

fairfieldwizard is offline   Reply With Quote
Old 12-29-2018, 10:10 PM   #2
I Think We're Lost!
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Brand: Still Looking
Model: Tiffin Wayfarer 24 BW
State: New York
Posts: 14,017
THOR #8860
It sounds like you've picked up some crud in the one-way valve that should be preventing this from happening. Water sin't supposed to be able to flow back through the line, and into the tank.

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Current coach: Tiffin Wayfarer 24 BW
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Old 12-29-2018, 10:18 PM   #3
Senior Member
Brand: Thor Motor Coach
Model: 2013 ACE 30.1
State: Alberta
Posts: 1,106
THOR #2631
Sounds like the usual failure of the anti backflow valve inside the water pump. There is a posting a little further down that is the same issue.


You hear the pump short cycling because the anti backflow valve is leaking.....so pump pressurizes the pipes and shuts off....but water leaks back to the fresh water tank through the leaky valve in the pump which causes a water pressure drop that starts the pump again. Suggested solution is to turn off the city water and run the water pump a few times to clear any obstructions in the valve. Then try turning on city water again and see if your overflow continues. The other option is replace the valve in the pump; replace the pump or you can purchase a stand alone anti-backflow valve and plumb it in series with the pump (make sure you orient the valve in the correct direction if you choose this option....but its a cheap solution with a bit of plumbing required) .
javelin is offline   Reply With Quote
Old 01-07-2019, 01:00 AM   #4
Brand: Thor Motor Coach
Model: Hurricane 29M
State: California
Posts: 67
THOR #7902
I originally posted this in the modification thread. This is obviously where it should be.

"I have a problem that is right up this line. While in AZ, we had very cold weather (22 degrees one night) and I noticed water coming out of the overflow in the gravity water fill. Turned off the city water and the overflow stopped. Storage tank was only about 1/4 full when we left home, and now it was full to over flowing. With the city water still turned off, I ran the water pump for a short time, and then turned the city water back on. No more water going to storage tank. The day before we left, I took off the city water hose so I could put it storage and not deal with it in the cold morning. Now, when I run the water pump, it goes out the city water fill! There must be a valve that controls which water (storage or city) goes where, and I think mine has gone bad.
Has anyone else experienced this? If so, what did you have to do to correct it?"

I have the freshwater schematic from Thor, but I do not see a reference to any valves.

SOLVED: Anyone want to guess what happens if you put the little wire mesh filter in the wrong way? It holds the little valve in the city water inlet open. Turned wire mesh around, problem gone.
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