12 volt fresh water shurflo water pump doesn't shut off

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lillobo

New member
Joined
Dec 2, 2017
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4
I have a weekend warrior toyhauler The shurflo pump never shuts off. Here is what I have done Swapped out for a new shur flo pump, replaced line from tank to pump all new fittings, water in tank. primed every way I can think of, check city water gravity feed vavlve door . If I remove the intake line from the tank to the pump and put on a makeshift fitting to a water bucket it stops. That"s why I replaced the tank line. The Pump does not have a strainer in line and the tank is not plugged up. Does a strainer do anything to help maintain the prime and pressure? any help would be appreciated
 
Welcome to the forum.
How do you fill your water tank. You may have a gravity fill port AND possibly a valve which when hooked up to shore power, all you need to do is open this valve. One position of this valve may point to words similar to "Tank Fill" and the other position may be "Normal".  Make sure that valve is in "Normal" position. If it's still in Tank Fill position, all you're doing is circulating the water right back to the tank.
 
That may be why the previous owner cut the fill valve out of my plumbing and capped off the lines.  Unfortunately he didn't leave enough on the lines to cut off his caps and re-plumb the fill valve without major work.  I hate filling a 100 gal tank through the gravity port.
 
Old_Crow said:
That may be why the previous owner cut the fill valve out of my plumbing and capped off the lines.  Unfortunately he didn't leave enough on the lines to cut off his caps and re-plumb the fill valve without major work.  I hate filling a 100 gal tank through the gravity port.

Don't know why he would do that. If the valve was leaking by, it would be so much easier to just change it out.
 
Anybody that has been bitten by the Tank Fill/City Water mixup will never forget it.  Anytime I hear that pump running continuous I immediately know the cause.  It usually happens because when I disconnect from City Water the line holds pressure until I switch the valve over to Tank Fill and that relieves the pressure.  Then I forget to switch it back.  Anyway, easiest fix I have come across yet.

Bill
 
Some valve manufacturer must have come up with a "cost-reduced" (aka cheap crap) fill valve and sold it to some major RV makers, cause this problem was rare until the last couple years. Before that, the most common problem was the check valve in the pump allowing leak-back, resulting in a periodic blip of the pump to restore pressure.
 
I have the gravity feed/ city water combination door. I have searched this rig over the only valves I can find are 2 drain valves. A large one that comes directly from the fresh water tank and a smaller one under the water heater.  I removed the combination door, unscrewed the fitting from city water and capped it still same problem. If I put a make shift supply to the pump from a bucket it works just like its supposed to. this tells me its the line coming from the tank but I've replaced this line and fittings 2 times, still exact same problem. The line is about 6 feet comes from the tank under the trailer has a 8 inch riser with a 90 degree to the pump inlet so this line has 3 90's and less that 7 feet of 1/2 plastic tubing
No clogs water free flows from the tank when tubing is off. No low voltage new pump same characteristics with old pump. Please help 
 
How about telling us what you have for a RV?  Go into your profile and create a signature of yourself telling us a little bit about you. If you're lucky, we may have a member with the same RV.
 
Weekend warrior 2000 1800fk I've gone out again no valves that I can find.This has to have a air leak on the suction side of the pump but I feel I have done everything that should remedy this unless the pump is creating a vortex inside the tank I have no idea where the air is coming from
 
Do you have pretty good access to the tank? Can you find the line from shore power which fills the tank? If you can, disconnect it and plug the hole to the tank using someone's finger or similar. You don't want to drain then tank out of that fitting.  Then start the pump and see if you get water out of the disconnected line.
 
Rene T said:
Don't know why he would do that. If the valve was leaking by, it would be so much easier to just change it out.

This particular section of the plumbing in my coach is regular CPVC with glued connections.  Even the valve was plastic.  The valve was right at the connections to the pump, so even if they had to replace it, it would have required re-making at least one of those lines. 
I still have the valve, I've tried to blow through it, and I'm fairly convinced that he removed the valve because he left it on one or more times.
 
Your analysis is spot on.  It seems clear from your description that there is an air leak on the suction side. It doesn't take much - a hairline crack in a hose or pipe, or in one of the fittings. Just gonna have to hunt it down and replace, or replace the entire line.
 
Gary RV_Wizard said:
Your analysis is spot on.  "It seems clear from your description that there is an air leak on the suction side. It doesn't take much - a hairline crack in a hose or pipe, or in one of the fittings. Just gonna have to hunt it down and replace, or replace the entire line.

The OP said they "replaced line from tank to pump all new fittings". Maybe the threaded boss in the tank is cracked, if that's what they have. If there is a air leak, I'm surprised it doesn't leak water when the tank is full.

To the OP, try filling the tank all the way and check around.
 
Sorry, I guess I glossed over that line about replacing the line.

Regardless, something is broken in that path.  While the plumbing is awkward, it is not unreasonable and I think we can assume that other Weekend Warrior owners are able to use their water pump as it came from the factory some years ago.

Has it been verified that the connection at the tank actually has water at that level?  I see where you said "water free flows from the tank when tubing is off", but need to ask to be sure.  Might it be mounted high, with a continued tube inside the tank to get closer to the bottom? If that tube was disconnected from the outlet fitting, the pump gets air at least some of the time.

One trick, though not a simple one, is to pressurize the tank and look for leaks in tank or line. Have to block the tank vent and gravity filler inlet, and be careful to use relatively low pressure, maybe 30 psi.
 
there is no place water is leaking from the tank the out let comes right out of the bottom no drips no nothing? I can see the gravity line into the tank changing this would be a pain. I have no leaks any where ???? I can see air bubbles come out of the pump into the pressure side of the line  But I don't know what to change to stop it
 
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