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Water pump pressure control switch

AndyP

AndyP

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Had to go to my SILs cottage yesterday to do some watering for her. She has a well on the property and a submersible pump to pump the water out. Problem is the pump is switched on from the house and is therefore always on until it is switched off.
It must be possible to fit a pressure control switch so that the pump is only on when a tap (or trigger gun on the end of the house) is open?
Does such a switch exist for this type of external use? I would like to think I could fit it inside the well for protection from the elements with an tap on the outside of the well.

Any ideas on what I need to look for or specify?
 
Aren't there separate flow switches for showers? I could see that working, but there would still power to the switch.
 
http://www.ebay.co.uk/itm/Automatic-Gar ... 5pOm2FRpeg

s-l500.jpg


Any good?
 
This is a knotty one.
With the well pump switched off there is no pressure change to detect when the demand tap is opened.
I 've seen pumps with a small pressure chamber designed to maintain increased tap pressure in lots of the French DIY shed but i would expect them to need a low pressure water supply and not have any self priming capability. It could well be that connecting the well pump in parallel with the boost pump motor, you could get the effect you want.

This is the type of pump I mean. http://www.ebay.co.uk/itm/Mains-Water-B ... SwSzdXBS1Y

Maybe try and find an old one on the second hand French site lebcoin or something similar? to play with.

Might involve relays though :lol: :lol:

Bob
 
I suppose the easiest way, if you've the space, is to pump up to a header tank and then let gravity do the rest? Tank can be controlled by float switches.

Rod
 
I'm not suggesting that the link's products are used, but I see an analogy between my domestic shower water and Andy's SIL's well situation.

I live in a chalet bungalow and the HW cylinder is on one side and the bathroom on the other. Therefore, the the shower pump and cylinder are below the shower head and the pipework has to go over the top loft to get to the shower.

So, the plumber installed a negative head pump, which has a small pressure chamber and flow switch which has enough stored pressure to get the water up and over the loft to the bathroom. It detects when the shower is switched on and activates the pump. When the shower is turned off, it continues to operate for 3 seconds to re-pressurise the chamber ready for the next time.

http://www.stuart-turner.co.uk/media/13 ... sTypes.pdf

I wonder if the principle could be employed with a well.
 
A controller like the one in Robert's post was what my simple little head had in mine. But I ma worried by Bob's comments about what happens when the pump is switched off.

I found another one that states a check valve prevents the pipeline from losing pressure. Would this solve the problem?

b_Home_Automatic_Water_Pump_Controller_09.jpg


It all seemed so simple in my mind. :D

I will pick up some terminals next week to complete the Camvac relay switching project.
 
I'd be wary of a check valve holding pressure of several feet of water for days/weeks between uses.

Note that the diagram says the pump must be primed for which read re-primed every now and then.

I still think the lift pump slaved to the high pressure pump and the whole thing left powered up ( but not running) will deal with any leakage through a check valve and give water on demand.

Bob
 
Thanks Bob, I don't think we can run to that sort of expense. I will have a chat when she gets back from holiday. The well is at the lowest part of the property but I reckon the easiest and cheapest solution is as per Rod's suggestion. I can get a cubic metre water tank in a cage (ex agricultural) and hide it at the top of the garden, fill it with the existing pump probably only 3 or 4 times a year then use gravity to water the garden.
 
For a borehole feeding a tap we use a pump at the bottom of the borehole which runs until a pressure switch is triggered, when the tap is opened the pressure drops so the pump starts again then stops momentarily after the tap is closed. It does require power to be present all the time that the tap is likely to be used. There is also an expansion vessel with a schraeder type valve for pressurising which I can't remember precisely how it is used.
 
Stargazer":3sg3qyec said:
For a borehole feeding a tap we use a pump at the bottom of the borehole which runs until a pressure switch is triggered, when the tap is opened the pressure drops so the pump starts again then stops momentarily after the tap is closed. It does require power to be present all the time that the tap is likely to be used. There is also an expansion vessel with a schraeder type valve for pressurising which I can't remember precisely how it is used.
Click to expand...


That sounds very similar to the principal in the negative head shower pump in my post above. The pressure vessel attached to the pump in that has a shraeder valve to prime it, which is then re primed for 3 seconds after the tap is switched off.
 
I did not mention that the pump is a submersible one that I am told is at least 2m under the the water. Does this make any difference to the self priming problem and holding pressure for the weeks that it may go unused?
 
The submersible pump will be automatically primed by the 2m head of water all the time it is dunked in the well.
I did not think you were going to use a surface pump now just a tank at ground level.

Just a thought about your suggestion of it only needing to be topped up a few times a year. This suggests the water will be sitting in the tank for weeks/months and so it will grow all sorts of things in it. This wont harm the plants but pipes/taps/filters might get clogged especially with the near zero head on that part of the system.
I'd suggest at the very least, draining the tank at the end of the season of use. This should kill any growths off or at least retard them, maybe chuck in a bottle of cheap bleach, mix with a little fresh well water enough to coat the bottom of the tank and leave in there all winter and flush through into a ditch on the first use in spring.

Bob
 
I am still mulling and discussing as I speak with SIL who is not keen on the cubic metre caged ex agricultural water storage tank, purely from an aesthetic point of view. BTW I have one behind my polytunnel which I fill 2 or 3 times a year and although not tested for purity even after 6 months the water still looks clean.

So going back to Roberts post and this type of pressure control switch. Will it work with the submersible pump without the need for further valves, pressure chambers etc?
s-l500.jpg
 
The problem with the ebay one is that I can't make any sense of the description which reads:-

"This pump controller constantly keeps the pressure in the water system at home or in the garden irrigation. When pressure decrease the pump shuts off automatically and turns on again as soon as the pressure becomes constant. "

If this is correct, then how do you see it working in your application Andy?

If they have mis-translated from German and they mean "increase" instead of "decrease" then it might work.

Perhaps under the chrome cover there is a pressure sensing diaphragm and a very tiny pressure vessel?

You could try asking them if there is an error but given the language difference, I'd be wary of launching into a detailed Q&A session about your application.

Caveat emptor but it is quite cheap to take a punt on?

Bob
 
Further thought:

The controller might have a NRV inside but if it doesn't you might find it cycling too rapidly and quickly use up it's life time of 100k operations . So if you get this problem then an inline NRV in the pipe up from the pump should sort it out.

Bob
 
Morning Andy

Problem is the pump is switched on from the house and is therefore always on until it is switched off.

Why don't you install a weather-proof switch outside?

Cheers

Dave
 
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