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Hooking up a well


H F

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Not sure if this is the right forum.

 

We have a walled well (which probably dates back to the mid-1800s) - the previous owners measured it by dropping a rope down and claim it's 60-feet deep.

 

We are now ready to try and put this well to good use to water the garden.

 

We need advice on what the best way would be to approach this and what kind of pump would be best suited.

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We have a well that feeds an outside tap, it has a pump down the well wired to a switch next to the tap, the tap is always turned on and when you switch the switch on it operates the pump. 

I can’t tell you about the pump as I’ve never seen it as it’s down a big hole. 

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4 minutes ago, AnonymousBosch said:

Hello, and welcome. What a good idea. And I must say, I'm jealous: I'd love to have your little challenge.

May I suggest that you consider maintaining the well of the wall before anything else?

 

May I ask what you mean by "maintaining the well of the wall"?

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5 minutes ago, Russell griffiths said:

We have a well that feeds an outside tap, it has a pump down the well wired to a switch next to the tap, the tap is always turned on and when you switch the switch on it operates the pump. 

I can’t tell you about the pump as I’ve never seen it as it’s down a big hole. 

 Great point about the switch for power - I was going to have this near the tap too. Do you know the brand of your pump, and how long has this been running now?

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The snag with the submersible pumps that places like Screwfix sell is that they are all float switch operated, so won't turn on and off when you open a tap, without some playing around and making underwater mains cable connections to the switch cable and adding a pressure switch and small pressure vessel.  To be able to just turn on a tap and have a pump start needs a pump that has a pressure switch that turns the pump on when the pressure drops from opening the tap, plus small pressure vessel to prevent the pump from short cycling. 

 

There are two types of pump, and which you choose depends on how far down the water level is at it's lowest.  No non-submersible pump will draw up more than about 8 to 10m, so if the water never falls this far below the height of the pump, then you can look to use an above water pump set. 

 

If the water level is likely to drop below about 8m from the top, then it would be best to fit a submersible pump with a pressure controller.  Something like this would do the job (again, just picked at random to illustrate the type of system): https://pumpexpress.co.uk/shop/the-peak-bundle/

 

We use a borehole for our water supply and I've found the Polish made IBO pumps to be pretty good value and reliable.  You could put together a system using parts from them fairly cheaply, for example:

 

Submersible pump (OK for use at depth): https://www.ebay.co.uk/itm/IBO-3-SQIBO-0-55-Borehole-Deep-Well-Water-Submersible-Electric-PUMP-14m-cable/172266242720?hash=item281bde42a0:g:UkEAAOSwepJXX-Aj

 

Pressure vessel: https://www.ebay.co.uk/itm/Druckkessel-24-l-mit-Membran-Druckbehalter-Membrankessel/182952158436?hash=item2a98cc64e4:g:HYgAAMXQNOZRCnkG

 

Pressure switch: https://www.ebay.co.uk/itm/IBO-PC-59-Intelligent-Automatic-Pump-Control-System-dry-running-run-protection/182278785811?hash=item2a70a98b13:g:EDcAAOSw8vZXMzy2

 

 

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Thanks JS - that's a very detailed response.

 

The water doesn't replenish at a rapid rate, so would have a bit cautious if we did a lot of watering in the garden. The one thing I've struggled to get my head around is switching pump on and off if it is connected to a tap, for example, and how that would work exactly. Is it as simple as turning the power on, and water would be there on demand. If the tap was "closed" and the pump was on, would that damage the pump? Perhaps it's better to just have the switch with an open hose so the water just comes out when the switch is turned on.  

 

I've looked at your recommendations - thank you. I was initially looking at this one because I can lower it to 15m: https://www.kaercher.com/int/home-garden/pumps/irrigation-pumps/bp-4-deep-well-16454210.html

 

 I honesty didn't think this exercise would require so much brain power.

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Can you install a tank somewhere and fill that up slowly or in bursts, then water the garden from that? You wouldn't need much storage if you're able to replenish fairly consistently.

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Hi Jack - thanks for the suggestion. From an aesthetics perspective, a tank wouldn't work in our back garden, but that's a good idea. That would I would fill the tank using the pump; how would I get pressurised water to a hose then? Would I need another pump?

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3 minutes ago, Home Farm said:

Thanks JS - that's a very detailed response.

 

The water doesn't replenish at a rapid rate, so would have a bit cautious if we did a lot of watering in the garden. The one thing I've struggled to get my head around is switching pump on and off if it is connected to a tap, for example, and how that would work exactly. Is it as simple as turning the power on, and water would be there on demand. If the tap was "closed" and the pump was on, would that damage the pump? Perhaps it's better to just have the switch with an open hose so the water just comes out when the switch is turned on.  

 

I've looked at your recommendations - thank you. I was initially looking at this one because I can lower it to 15m: https://www.kaercher.com/int/home-garden/pumps/irrigation-pumps/bp-4-deep-well-16454210.html

 

 I honesty didn't think this exercise would require so much brain power.

 

The way the tap controls the pump is via the pressure switch, in conjunction with the pressure vessel, which allows for the fact that water is incompressible (to all intents and purposes).  What happens is this. 

 

When power is turned on and the tap is closed, the pump operates until the pressure in the pipe to the tap reaches the switch turn off pressure, typically around 3 bar.  The pump then turns off and that pressure is held, as there is a non-return valve in the pipe to the pump. 

 

When the tap is opened water starts to flow, and the pressure drops.  When the pressure drops below the turn on pressure, typically about 2 bar, the pump switches on to continue to supply water.

 

If the rate at which the pump can supply water is greater than the rate at which it's being used, then the pressure will increase.  When it reaches the turn off pressure the pump will turn off, until the pressure drops back to the turn on point again.

 

If the tap is turned off, with the pump running, the pressure will increase until it reaches the turn off pressure, when the pump will turn off and the system will just sit pressurised, ready for use.

 

The advantage of this system is that the pump can be placed low down in the well, so it can always draw water, and there's no need to mess about switching power on and off.  The tap can be treated just like any other tap.  Water will flow when the tap is turned on and stop flowing when the tap is turned off, plus the pressure will stay reasonably constant, between 2 and 3 bar.

 

An alternative is to not have a tap, and just have a pump down the well with a suitable weatherproof switch to turn it on and off.  This doesn't allow for any flow variation, as the pump will be either producing water at it's maximum capacity when turned on, or not pumping at all when turned off.  Even a small submersible pump will deliver maybe three times or more of the flow rate from a normal size outdoor tap, and so may be a bit difficult to use for delicate watering.

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That's great JS - demystified the pressure for me. Thank you so much.

 

Has anyone ever used the BP 4 DEEP WELL from Karcher? Any idea if they're any good/reliable?

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6 minutes ago, Home Farm said:

That's great JS - demystified the pressure for me. Thank you so much.

 

Has anyone ever used the BP 4 DEEP WELL from Karcher? Any idea if they're any good/reliable?

 

 

Looks just like a standard submersible pump with a pressure switch to me, and it doesn't seem to have a pressure vessel, so it will probably pulse on and off a lot in use.  How much is it?  The bits needed to do this should be around £110 or so for one with no pressure vessel or ~£140 for one with one (for a submersible pump).  If the surface of the water never drops lower than about 8m below where you can fit a pump, then you could look at a cheap surface pump set like this for ~£70: https://www.ebay.co.uk/itm/IBO1-WZI250-BOOSTER-WATER-PUMP-portable-small-electric-house-24L-pressure-VESSEL/172442502988?hash=item28265fc74c:g:JOkAAOSwvO5bs3Kr

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I think the BP 4, when I look at it a few months ago (before I got intimidated by the prospect of installing the pump) was around £220, which was pricy (I thought).

 

I think I'll consider the options you've provided - we don't need anything too pricey for this.

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1 minute ago, Home Farm said:

I think the BP 4, when I look at it a few months ago (before I got intimidated by the prospect of installing the pump) was around £220, which was pricy (I thought).

 

I think I'll consider the options you've provided - we don't need anything too pricey for this.

 

 

I've just looked in detail at the spec for that Karcher pump, and it has no controls at all, just an on/off switch.  The equivalent IBO pump (would do exactly the same thing) would be this one, for £74: https://www.ebay.co.uk/itm/IBO-3-SQIBO-0-55-Borehole-Deep-Well-Water-Submersible-Electric-PUMP-14m-cable/172266242720?hash=item281bde42a0:g:UkEAAOSwepJXX-Aj

 

The snag with this, and the Karcher one, is that it would be all or nothing, and could not be connected to a tap.  The pipe from it would have to run directly to the hose or irrigation run, with water being turned on full by switching the pump on.

 

When I was pumping out our borehole I had a submersible pump down the hole connected to a length of 25mm MDPE pipe, and just switched it on, with no controls.  It pumped around 30 litres per minute of water, which is a lot, maybe three times more than a typical shower.  Watering a garden with it would have needed some thought, as I think the only sensible approach might have been to install fixed irrigation pipes and sprinklers, so that there was no need to throttle the flow rate.  One problem with just putting a tap directly on a pump outlet is that as the tap closes the pressure rises, by far more than it does with a tap running from the mains.  Even the small 700 W pump I was using would run at around 6 or 7 bar pressure with a tap partially closed, with a jet of water that was more akin to a pressure washer.  That's the big advantage of using a pressure switch and pressure vessel arrangement, it keeps the pressure down to a manageable level, even with the tap almost closed.

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  • 7 months later...
On 21/07/2019 at 08:31, Triassic said:

I agree with Dave, keep it simple, all you need it an on/off switch by the outlet (no tap).


So is what you’re suggesting is to have a switch next to the tap. Turn it in, and the water flows from the tap. Turn it off, no water coming from the tap. Is that right?

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