How do I prime this bore pump

[Arron]

We have a holiday home on the NSW Central Coast. There are a couple of sand spears (bores) in the back yard and we have 2 old Billabong piston pumps running off these to water the lawns. They have run reliably for the 8 years we have owned the place - and probably for many years beforehand - until recently when one stopped pumping water.

The first thing I did was check the valves and the operation of the piston. All seems to be normal - though I'm no expert.

So I figured I would just prime the pump and get it going - then see if any problem materialised.

So I removed the priming plug on the pump itself, stuck a hose down it, filled it up with water, started the pump - but no result. I did this numerous times - no result. If I left the hose running in the priming hole while running the pump then the pressure in the receiving cylinder slowly built up, but it still didnt work on its own.

So I think I'm doing something wrong with my priming.

Should I be trying to fill the sand spear up with water first ? I think the pipe down to the water table is now partly or fully dry, and when I put water in then the non-return valve at the top of the spear is preventing any water from flowing down into it. Furthermore, I cant really imagine the pump has enough suction to fill the pipe on its own, drawing water all the way up from the water table. So maybe the pipe down to the water table is acting like one huge air-lock ?

So can someone give me some guidance on the correct way to prime a pump ?

Google is not helping.

cheers and thanks
Arron


I have attached a couple of photos:
one shows the pump as it sits now. There is a short pipe through the wall of the garage, then a 90 downturn to the sand spear (second image). At the top of the spear you can see a bulge - that's the non-return valve.

364619364620

[burraboy]

Dry buckets can be a problem on these, especially if they haven't been used for a while, and I have always put the non return valve so the entire suction pipe can be flooded. No airlocks that way.

[rustynail]

You will need to prime the suction side (the spear) if it has lost prime. This will mean disconnecting at well side of non return valve, prime and refit. Then prime other side of non return valve. You may wish to consider a small bypass line and stop cock for the non return valve. You would then be able to prime without undoing the main line.
Also, as Burraboy said, check your buckets and springs. They should snap back when lifted.
Hope this helps.

[malb]

In addition to above, I would also check the return valve for a damaged seat or seal, or even a couple of specks of sand between seat and seal. Unless all is 100% perfect, it will allow leak back through the spear whenever the pump is not running which will ultimately break the prime.

[Arron]

Thanks for the replies guys.
Sounds logical.
by the way, what are 'buckets'. haven't heard that term.

cheers
arron

[burraboy]

what are 'buckets'. haven't heard that term.

the cup shaped leather washers on the piston

[Arron]

OK. I went up to the place today to try and fix this.

I'm thinking the first thing I need to do to repair the situation is fill the spear pipe up with water. It appears to be dry and there being no way a pump would pull that much air and water up a 2 meter pipe. After that, I thought, I'd reattach and prime the pump.

So I disconnected the pipe from the pump to the spear pipe, and removed the non-return valve at the top, so I was looking straight down the naked pipe. Then I put a hose down the pipe and pumped about an Olympic sized swimming pool worth of water down the pipe, and it all disappeared. The pipe remained dry.

I'm not sure what is going on here.

I thought that in this coastal community, where almost every home has a spear pump, that every old timer would know how to fix these, but now I ask around I cant find anyone with hands-on experience. Best so far is our neighbour who has at least seen a spear point being sunk.

The neighbour suggests my problem is that there is probably a non-return valve immediately above the spear point that has failed. He suggests pulling the spear and pipe completely out of the ground, servicing and reinserting.

My problem is

1. it sounds a little unlikely to me that there would be a non-return valve at both the top and bottom of the pipe. Any ideas ?

2. I think it will be relatively easy to pull the spear up, but I'm not sure how easy it will be to get it back down again. Its about 2 meters deep. Its only sand so I suspect the hole will start collapsing as soon as I pull the spear out. Anyone done this ?

Any advice greatly appreciated.
cheers
Arron

[malb]

1. it sounds a little unlikely to me that there would be a non-return valve at both the top and bottom of the pipe. Any ideas ?


It seems logical to think along these lines BUT what if the one near the pump was added because the one at the spear was failing and it was a lot easier to add a second one above ground than pull the whole thing out of the ground to fix the underground one. You get two non return valves a dud underground and a better one above ground, also prone to wear because of the same issues that killed the lower one. Once the top one allows leak back, your shot and cant fill the line to reprime it because whatever water you put in drains straight through. Ask around a bit and see if others with a nominally similar setup have the return valve at the pump. Probably not a lot of value in looking at the other unit of yours to see if it has both, as if the UG valve on one unit failed forcing them to install an above ground valve on it, you would probably be smart and do the same with the second unit to avoid a second callout later when it looses prime and needs sorting.

My first thought when you mentioned the non return being above ground was that it was an odd place for it as they are normally located as low in the system as possible. But if it was added to avoid pulling and reworking the spear and resetting it, that would make sense.

Any possibility that you can run both pumps off the viable spear for a time to get through summer while you pull the dry unit and examine/ repair it.

[chambezio]

Mate, I think you will find that you will have a non-return valve right at the bottom of the spear. It stands to reason......we live in a rural area. We catch rain water in above ground tanks that flood prime a pressure system under the house....no non-return valve. Our bore is 30 meters down with a non-return valve at the bottom. You have to exclude any air to be able to suck water.

[A Duke]

Hi,
I think the valve at the bottom is known as the foot valve.
Not that that helps, you could come up some imaginative names of your own if it is ****.
Regards

[rustynail]

If the spear has been placed in what was a permanent wet spot, a foot valve may not have been necessary. Water may have risen up the pipe enough to allow an above ground non return valve to be fitted. This would mean all servicing above ground level. Nice. One problem....if the well starts to dry off, the air pocket enlarges and the pump fails to prime.
The normal set up is a foot valve (non return valve) at the spear point. This maintains a constant full length prime, until the foot valve develops a leak. Then the spear must be lifted and the problem fixed. A cased bore makes this process much easier in loose sand.

[Wood Collector]

My concern would be that maybe the area that the bore was sucking from has lowered the water table so the at the suction pipe is not sitting in water. If you can slide a casing around the outside of the boar suction pipe and down to the water. That will prevent the hole from caving in. Sorry that I cant help you much more than this as the only boar that I have had experience with was one that had an outside casing to prevent the boar from collapsing.

[Arron]

thanks for the replies guys.

I read from this that there may be a foot valve, or there may not, but most likely there is. The valve may be faulty, or the water table may have simply dropped. The fact the other spear pump is still going indicates to me the likelihood is that the water table hasn't changed.

Or maybe it has. A neighbour told me that another neighbour spent all last weekend working on his pump - so maybe the table dropped and his was affected and one of mine was close enough to the upper limit to be affected, the other isn't. Unfortunately, the neighbour who was working on his pump is a holiday home owner too, and he doesn't come up very often so its pretty unlikely I'll be able to catch him at his place.

Either way, it seems the next step is to remove the spear and see whats what. I think removing it will be easy as it wriggles a bit - but not sure how to get it back in. Assuming I remove it and there is a bit of collapse back into the hole, and the spear can be pushed most of the way back into its hole, can I just bang it down the rest of the way with brute force and a lump hammer ?

cheers
Arron

[rustynail]

Short answer is yes. You mention movement in the spear, this may mean it is already cased. That would be a win. Either way, the spear needs to come up, after which you will know whats going on down there.

[Arron]

Well I was up at the holiday home again today, and decided to remove the spear and find out what is going on. Wasn't sure whether I'd be able to get it back in again or not - decided to cross that bridge when I came to it.

Unfortunately, no amount of levering and banging and tugging would move the spear. Not even a millimetre. They are supposed to be only about 3 metres deep in the area too.

So with me being unable to get it out, not sure what condition it would be when it came out, not sure whether I could get it back in, and suspecting I still had a few hurdles to overcome on the pump end of things, I decided to abandon it. This is not DIY material - not for me anyway.

The other spear point and pump are still running well, and with a complicated system of timers and pipes I modified it so it will water alternate sides of the lawn on alternate days.

Seems to be working.

cheers and thanks for the advice.

Arron

[rustynail]

If the bore is not cased, there is no way you would be able to lift a 3m deep spear by hand. The friction of the sand would be well above your physical capability. A bobcat or tractor with hydraulics would be the go. The other way is using an elevated wheel, thats how deep bore pumps are lifted. Cable attached to spear, run up over wheel, other end attached to vehicle and head for the pub, too easy!

[pker]

If the spear is encased , you can get it out by using your other water supply. I have a spear that is down approx. 2.5metres. To clean the strainer every few years I remove the spear by joining a 3 metre curtain rod to the town supply hose & sticking it down between the spear and the casing. Slowly working deeper the pressure from the town water softens the tightly packed sand between the spear and the casing. You can usually start to move the spear by twisting first. Sometimes they have gravel around the strainer itself , but I have never worried about replacing it. This method should work if it is in sand only.
Hoping this helps. pker