Water - Dock side is back flowing into tank

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ply17410

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Water from my dockside hookup is back flowing into my fresh water tank.

I have a Shurflo 5901-0201 freshwater supply pump.

Was wondering if the Shurflo acts as the back flow prevention or is the norm to have an independent check valve to prevent shore side water from flowing into the tank. I'll pickup maybe 20 gals back flowing over a normal weekend when we are on dockside water.

If the Shurflo backflow device, can it be repaired?

Boat is a Regal 3560 2005.

Thanks,

Bob H
 
If the pump cycles when no faucets are open, I am thinking there is some repair in order. HOWEVER on our boat we have a check valve that prevents dockside water from running backwards through the pump.
 
quote:
Originally posted by ply17410

Water from my dockside hookup is back flowing into my fresh water tank.

I have a Shurflo 5901-0201 freshwater supply pump.

Was wondering if the Shurflo acts as the back flow prevention or is the norm to have an independent check valve to prevent shore side water from flowing into the tank. I'll pickup maybe 20 gals back flowing over a normal weekend when we are on dockside water.

If the Shurflo backflow device, can it be repaired?

Boat is a Regal 3560 2005.

Click to expand...
I feel the need to post this question so often, I ought to save it so I can just paste it into a post.

Is this a "new" problem, something that happened recently or has it been like this since the boat was new?

The reason I ask is, if it used to be fine but now it's a problem, something has been changed or something is broken and needs to be repaired. In this case, your check valve may be stuck open or at least leaking internally.

If it has been this way since the boat was new, it's more likely a design problem and you may have to change things around or add components.
 
there is a valve on my fw system so you can fill the tanks while hooked up to dock water instead of the deck fill. i wasnt aware of this til the valve went bad and filled both tanks then overflowed out the tank vents.
 
Just another reason I never hook up to shore water...
 
to answer your question, yes the pump is also a back flow device so that your water pressure doesnt fall as it pushes back thru the pump. that said there could be more than one source of your back flow challenges. start with the pressure your getting into the boat. there is a pressure regulator built into the dockside water inlet that should drop the incoming pressure to approx 20psi. if that device fails you could exceed the ability of the pump to act as a back flow. as others have noted a previous owner could have fitted a tank fill valve in the boat somewhere. i dont believe that regal would installed such a valve as it might allow you to burst the tank if the vent were to be come partially blocked.
 
quote:
Originally posted by stmbtwle

Just another reason I never hook up to shore water...
Click to expand...

I cannot hook up to city water. I have the ability to change that, but like you, I wouldn't do it. There are far too many risks for a very small benefit.

Without a city water connection, I turn on a faucet or shower and water comes out. When it doesn't, I simply refill my tanks. No problem.
 
I had this same problem on my 1977 Chris Craft. I determined the valve that controls the flow to the water tank was bad and leaking through. The valve is in the middle of a control manifold so I cut the copper and sweated on an end. I cut the tee out and ran it directly to the pump, but never tested it.

The marina is about to shut off the water to the dock and I can't get water from the tank to the pump. The pump is old, so I thought putting a shop vac on it would pull the water. No good. I replaced the back flow valve. It was suggested I had a leak in my supply line. I just ran new pex. When I pulled the hose off the tank, it drained into the bilge, no problem. I brought in a five gallon pail of water and ran it direct to the pump. Water ran through the pump and out the faucet, No problem.

The route the supply hose runs, rises about four feet above the tank and the water pump is about 18" above the tank. The supply line is about 20' long.

This is making me nuts. The only thing I can think of, is that something happened when the water tank was pressurized. Could the vent be clogged and would that stop all water from coming to the pump?

Any experience would be appreciated.

Billy K.
 
Have you primed the pump? Is the check valve mounted in the right direction? Clogged vent is also a good suspect.
 
These diaphragm pumps have a number of check valves inside which while part of the pump also prevent water from back flowing to th tank. I have seen debris struck on one or more of the valves reducing pressure and flow, and that would also allow water to flow into the tank when hooked up.

Pull the pump, open the top and you ll see the valves, make sure one or two aren't stuck open.

That said there should be a check valve between the dockside supply and the pump.
 
I first replaced the valve body of the pump. Still had the problem. So I replaced the complete Shurflo pump and that corrected the problem.

According to Shurflo the pump acts as the check valve.
 
Don't depend on he pump as a back flow device. Install a check valve. Don't leave the city water unattended. Purchase and install a resetable water metering device in your shore water supply hose. These devices shut off the water after X number of gallons. Helps prevent the sinking of your boat if something inside springs a leak.
 
I rechecked everything and still no good. I removed the hose from the water tank and ran a hose along the floor. Although the pump would still not pull enough water, it did pull some. I hooked up the shop vac again and got the water to the end of the hose. I put it on the pump and got it to work, but not with the flow I had in the spring. It also tripped the breaker twice. I pulled the pump and am going to have the motor and pump serviced.

Thanks for your inputs.

Billy K.
 
quote:
Originally posted by BillyK

I had this same problem on my 1977 Chris Craft. I determined the valve that controls the flow to the water tank was bad and leaking through. The valve is in the middle of a control manifold so I cut the copper and sweated on an end. I cut the tee out and ran it directly to the pump, but never tested it.

The marina is about to shut off the water to the dock and I can't get water from the tank to the pump. The pump is old, so I thought putting a shop vac on it would pull the water. No good. I replaced the back flow valve. It was suggested I had a leak in my supply line. I just ran new pex. When I pulled the hose off the tank, it drained into the bilge, no problem. I brought in a five gallon pail of water and ran it direct to the pump. Water ran through the pump and out the faucet, No problem.

The route the supply hose runs, rises about four feet above the tank and the water pump is about 18" above the tank. The supply line is about 20' long.

This is making me nuts. The only thing I can think of, is that something happened when the water tank was pressurized. Could the vent be clogged and would that stop all water from coming to the pump?

Any experience would be appreciated.

Billy K.

Click to expand...


What kind of pump?
 
Marine Maid, I'll post a pic tomorrow morning.

Thanks,

Billy K.
 
I'm going to have the motor and pump checked out.

IMG_20131214_121316_zpsea5f4aad.jpg
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Thanks,

Billy K.
 
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