# Forum Home Renovation Pools, Spa & Water Features  Bore is driving me crazy.

## chromis

I have a above ground Davy pump on an old galvanised bore pipe with a check valve above the galvanised pipe, into PVC, elbow and into the pump. Everything works fine for a while then the irrigation just splutters and spits air. Then it just wont pump at all.  
So I thought maybe it's the check valve so replaced it and the pump primed fine and the sprinlers were working.  But in the process it blew off the fitting that feeds out to the irrigation solinoids. So I fixed that. Now the bloody pump won't prime.  
How can it not prime if there's a new check valve which should be closed.

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## SilentButDeadly

Was the check valve the one in the pump (many Daveys have one in the pump inlet) or external? 
What sort of nick is the impeller in?  I'm assuming that your bore is in sand and if the screen has failed in any way you may be thrashing a pump head of sand....at the cost of the impeller.  Sand may also be caught in the check valve/s. 
And finally......is the foot valve or inlet down the hole still below the water table?

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## chromis

> Was the check valve the one in the pump (many Daveys have one in the pump inlet) or external?  *It's an external check valve. Between the galvanised bore and the pump.*  
> What sort of nick is the impeller in? I'm assuming that your bore is in sand and if the screen has failed in any way you may be thrashing a pump head of sand....at the cost of the impeller. Sand may also be caught in the check valve/s.  *How do I assess if the impeller is in good nick? There's no crunching or unfamilar noise coming from the pump.*   *If stuff is getting caught in the check valve what can I do to stop it?* 
> And finally......is the foot valve or inlet down the hole still below the water table?

  Yes I put down a peice of polypipe and sucked out some water, plus when I pulled the pipe out, it was wet..   I thought maybe it had dropped below the water table but then again why would it work straight after I put a new valve in and then not the next time I turn it on.    Before I changed the check valve, when I was priming it I put my ear on the galvanised pipe below the check valve and I could hear water passing through. So I thought AHAH it's gotta be the valve. But now I dunno.

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## SilentButDeadly

The only way to check the impeller is to take apart the pump - remove the pump from the motor. 
To stop the sand you'll y need to screen the pump intake in the bore (most people seem to use flywire and a cable tie!). 
If the pump has two check valves on the intake side then remove one....shouldn't make any difference but simplicity is just fine. If you have to chose use the one in the pump (it'll be right where the suction line joins into the pump). 
Might be worth checking the integrity of the intake line too....any holes then it won't play.

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## chromis

The water is passing through the check valve so I guess it is stuck open. I put the check valve straight onto the bore pipe.  
Is there some kind of pre-filter I can get or will that interupt the flow.

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## SilentButDeadly

> The water is passing through the check valve so I guess it is stuck open. I put the check valve straight onto the bore pipe.  
> Is there some kind of pre-filter I can get or will that interupt the flow.

  You've lost me in the first paragraph....!  Is the new check valve no longer working? 
Pre-filter?  You can try the flywire & cable tie solution. Another option is a filter sock which you slide over the intake. Anything else will compromise suction....

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## chromis

By prefilter I meant something that could filter out the crap before it hits the checkvalve. 
It goes: water table==>galvanised pipe with male thread==>female to female check valve=====>skip a few parts====>intake to pump.  
So a filter to screw onto the threaded galvanised pipe and then on top of that the check valve.. 
Anyway I redid the whole lot from intake to outlet and swapped the bunnings check valve with a brass one. When I took the bunnings valve out and put some water in it, it leaked anyway. But the real issue was the whopping big piece of debris stuck in it. It cranks up every time now but no doubt it will get clogged again.  
When I went to the irrigation shop to get the valve the guy said nothing should be able to enter the bore pipe because the holes are so small. So perhaps because the pipe could be like 50 years old it has rusted enough to intermittently let crap through.

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## SilentButDeadly

> By prefilter I meant something that could filter out the crap before it hits the checkvalve. 
> It goes: water table==>galvanised pipe with male thread==>female to female check valve=====>skip a few parts====>intake to pump.  
> So a filter to screw onto the threaded galvanised pipe and then on top of that the check valve.. 
> Anyway I redid the whole lot from intake to outlet and swapped the bunnings check valve with a brass one. When I took the bunnings valve out and put some water in it, it leaked anyway. But the real issue was the whopping big piece of debris stuck in it. It cranks up every time now but no doubt it will get clogged again.  
> When I went to the irrigation shop to get the valve the guy said nothing should be able to enter the bore pipe because the holes are so small. So perhaps because the pipe could be like 50 years old it has rusted enough to intermittently let crap through.

  Sounds like you have it sorted.  If the bore has a bit of age to it then it is possible that the mesh screen on the bore case could fail but if it did that then the intake would block quickly and completely.  Another possibility is that the bore over time can become 'contaminated' with general crud that cakes the inside of the casing - if this detaches it can get sucked up. One further contributor is the suction pipe itself which can be corroded over time but since you've replaced this then you won't get further dramas. 
A foot valve like the one below from http://www.irrigationwarehouse.com.au/category77_1.htm down the hole will help screen out the worst of downhole crud and you can screen it futher by wrapping it in stainless steel mesh (but that might mean you clean it more frequently if there is a crud problem)

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