Hi everyone,

 

I am ready for phase two of our off grid journey... drilling a Borehole.

I understand a few things will be different to a normal borehole set up because of our solar system, I wanted to ask advice because I am not 100% sure if the borehole people are offering the best solution. 

I was advised that we need to have two pumps, a small borehole pump, around .37kw that can fill the tank during the day and a VSD pump that will then be used to supply the house and garden.

I have a few questions regarding the advice I received?

Will it not be better to get a VSD pump on the borehole side to then illuminate the need for a tank?  

Any advice will be appreciated.

Many thanks. 

Oelof

 

2 hours ago, Oelof said:

Will it not be better to get a VSD pump on the borehole side to then illuminate the need for a tank?  

If your tank is, say, a JoJo tank of 5000l and 8m or so above ground, then you should not need a pump from the tank and you'd have loads of water on tap, with gravity feed, this is from my perspective the correct way of doing it... to try and run only from a borehole, without a storage tank is not a good idea...

42 minutes ago, Kalahari Meerkat said:

If your tank is, say, a JoJo tank of 5000l and 8m or so above ground, then you should not need a pump from the tank and you'd have loads of water on tap, with gravity feed, this is from my perspective the correct way of doing it... to try and run only from a borehole, without a storage tank is not a good idea...

Thanks, it will indeed be a 5000l tank, but it will be gound level. Is a VSD pump then the way to go? 

12 minutes ago, Oelof said:

Thanks, it will indeed be a 5000l tank, but it will be gound level. Is a VSD pump then the way to go? 

Personally I'd say no, get the tank off the ground instead, I've seen the kind of ground level setups be more problematic than not, slight leak and pressure drop and the pump keeps on cycling on and off all the time, a real annoyance/wasted power and some wasted water... if you can have the tank 5m or higher off the ground, you'd be much better off and would not end up wasting power or water..., you can even consider a twofer, a 1000l tank at 8m and the 5000l tank at ground level with a pump, refilling the 1000l tank, maybe... the pump would have to have some safety inputs, like enough water in 5000l tank to allow pumping and the 1000l is not full, thus ok to pump, or something to that effect, we only have a 1000l, I think, tank up and if we're careful only need to pump water every 3d or 4th day, for household use. The pumping here is from the canal, or a steel dam and done manually rather than automatic, I pump water from the canal, into the garden 4 to 6 hours a day, I think a 3/4 horsepower motor near the canal, which also, on switch over of a tap, will fill up the 1000l tank. No other pumps involved...

Oelof, the advice given is correct but the pump that is supplied by the tank does not need to be a VSD pump an ordinary vane pump or a centrifugal pump like the one in the photo will also work.

The reason why there is a tank or tanks is for water storage because the borehole pump typically deliver a flow of 1000l/h and if you open a tap and the borehole pump is off then there would be no water, if the borehole pump is on and you open a tap then you will get quite a surprise.

 

In order for the pressure pump to work there must be a height difference between the outlet of the tank and the inlet of the pressure pump so in other words the outlet of the tank must be higher than the inlet of the pressure pump even if the outlet of the tank is 200mm above the inlet of the pressure pump it will work once all the air is bleeded out to the inlet of the pump.

On the outlet of the pressure pump I would also look at a couple of pressure tanks like these, then the pressure pump does not start and stop every time a tap is opened if only a cup or two of water is used.

 

Another factor that must be considered with borehole water is, is it fit for human consumption so have the water tested and if need be invest in a filter system with a UV sterilizer.

5 minutes ago, GerhardK83 said:

Oelof, the advice given is correct but the pump that is supplied by the tank does not need to be a VSD pump an ordinary vane pump or a centrifugal pump like the one in the photo will also work.

The reason why there is a tank or tanks is for water storage because the borehole pump typically deliver a flow of 1000l/h and if you open a tap and the borehole pump is off then there would be no water, if the borehole pump is on and you open a tap then you will get quite a surprise.

 

In order for the pressure pump to work there must be a height difference between the outlet of the tank and the inlet of the pressure pump so in other words the outlet of the tank must be higher than the inlet of the pressure pump even if the outlet of the tank is 200mm above the inlet of the pressure pump it will work once all the air is bleeded out to the inlet of the pump.

On the outlet of the pressure pump I would also look at a couple of pressure tanks like these, then the pressure pump does not start and stop every time a tap is opened if only a cup or two of water is used.

 

Another factor that must be considered with borehole water is, is it fit for human consumption so have the water tested and if need be invest in a filter system with a UV sterilizer.

Thanks for the feedback Gerhard. 

Hi Oelof,

 

Sounds like an exciting step in your off-grid journey! Regarding the setup, a VSD pump on the borehole side could indeed remove the need for a tank by adjusting based on demand. But having a tank gives you a buffer if your solar system isn’t always consistent or if you want extra water storage.

 

It really depends on how reliable your solar setup is. If it’s stable, the VSD pump could be a  easier  solution. the best thing to do is check with both your borehole and solar experts to ensure you’re covered.

 

Good luck!

 

 

Thanks for the feedback🙏

On 2024/10/23 at 6:35 PM, Oelof said:

Thanks, it will indeed be a 5000l tank, but it will be gound level. Is a VSD pump then the way to go? 

Yes go with the VSD pump, very efficient does the job properly.

Very similar requirements to what I have, I have gone with the following. Everything runs of the inverter/solar setup. 

 

550W borehole pump directly to 2050L Eco tank. Note that it actually draws closer to 1100W in use. 550W is the mechanical output after losses. 

https://hurricanepumps.co.za/product/4sd2-11pmsc-borehole-pump-complete-220v-0-55kw-standard-control-box/

 

Small float switch wired in with relay to switch off borehole pump when tank is full. This relay is wired in series with a Sonoff Wifi switch to achieve two things:

1. Only run borehole pump during solar generation hours. 

2. My borehole runs dry in 20 minutes - so pump is cycled on for 15 min and rests for 25 min. If I just leave it on it will burn when hole runs dry.  

 

https://www.robotics.org.za/FLOAT-PP-A

 

https://www.communica.co.za/products/hkd-relay-board-1ch-5v-30a-h-dut?utm_source=www.communica.co.za&variant=40357296734281&sfdr_ptcid=31591_617_693003716&sfdr_hash=819ef32481f79b959895de61be7a55c8&gad_source=4&gclid=Cj0KCQiAoae5BhCNARIsADVLzZdNzgAr7UZ2BPZbA28jL6Hv6LK4YEbmwNTnQgYTGR-SRk0JUR4zm2YaAg1KEALw_wcB

 

https://www.communica.co.za/products/sonoff-basicr2-wifi-smart-switch?utm_source=www.communica.co.za&variant=17568103727177&sfdr_ptcid=31591_617_495141755&sfdr_hash=16cc81e0e522b4c961daa757b77dd394&gad_source=4&gclid=Cj0KCQiAoae5BhCNARIsADVLzZefdr6bzPUVEQ0JmaxiJpcAtwZ6ivmIP-kn5nLtIMbucxsIEWh0T1IaAgwnEALw_wcB

 

Trade Professional VSD Pump to supply water from tank to house and garden. Works really well. 

 https://www.builders.co.za/Water-Tanks-and-Filtration/Water-Storage/Water-Tank-Pumps/Trade-Professional-1-2HP-VSD-Intelligent-Inverter-Jet-Water-Pump-900-W-nbsp--MCOP1481/p/000000000850004992?gad_source=1&gclid=Cj0KCQiAoae5BhCNARIsADVLzZfmkeTJLzhmDQ6H7_NQSfl32w6Xehcm2mFGxDy3eIKqAoPkMevTVtcaAlYXEALw_wcB&region_id=ZAGP00

 

 

 

 

Hey Oelof,

 

I dont disagree with anyone guess it comes down to your preference as well.

Having an above ground tank for storage will be beneficial as you will be able to have better control over usage. Having it pump directly from the hole to the house could be tricky unless your recovery rate on the hole is crazy high.

So even in the dry season when the recovery rate on the inevitably becomes longer, you will be safe knowing that your tank is full.

VSD pump for the win in my opinion, I will soon be upgrading to the DAB EsyBox Mini. I currently have a Hurricane booster pump and when you open the tap the pump is at full tilt whether you open the tap 5% or 100%…its a 1.1kw pump but pulls like 1.5-1.7kw when its on. With a VSD they are more efficient where the power consumption and flow rate adjusts accordingly to the demand you place when opening a tap…so its also more gentle on your inverter/s…it not heavy metal from the first second 🤣

I have a 0.55kw borehole pump from Hurricane Pumps as well, the tank has a float switch and will only switch the borehole pump on if the water drops below the level you set it at. Same as @Pieter v D. But at the moment its dry season so I am manually having to pump from the hole…so I will also be looking at using a Sonoff basic to control the borehole pump with more ease and also prevent the pump from being on when the hole is in recovery. During the wet season I had no issue tank would top up thoughout the day.

 

Good luck with the drilling, hope you used a specialist to pinpoint the drill location for you? Oh and DEFINITELY get a clean up crew as part of the process…

On 2024/11/06 at 8:59 AM, Pieter v D said:

Very similar requirements to what I have, I have gone with the following. Everything runs of the inverter/solar setup. 

 

550W borehole pump directly to 2050L Eco tank. Note that it actually draws closer to 1100W in use. 550W is the mechanical output after losses. 

https://hurricanepumps.co.za/product/4sd2-11pmsc-borehole-pump-complete-220v-0-55kw-standard-control-box/

 

Small float switch wired in with relay to switch off borehole pump when tank is full. This relay is wired in series with a Sonoff Wifi switch to achieve two things:

1. Only run borehole pump during solar generation hours. 

2. My borehole runs dry in 20 minutes - so pump is cycled on for 15 min and rests for 25 min. If I just leave it on it will burn when hole runs dry.  

 

https://www.robotics.org.za/FLOAT-PP-A

 

https://www.communica.co.za/products/hkd-relay-board-1ch-5v-30a-h-dut?utm_source=www.communica.co.za&variant=40357296734281&sfdr_ptcid=31591_617_693003716&sfdr_hash=819ef32481f79b959895de61be7a55c8&gad_source=4&gclid=Cj0KCQiAoae5BhCNARIsADVLzZdNzgAr7UZ2BPZbA28jL6Hv6LK4YEbmwNTnQgYTGR-SRk0JUR4zm2YaAg1KEALw_wcB

 

https://www.communica.co.za/products/sonoff-basicr2-wifi-smart-switch?utm_source=www.communica.co.za&variant=17568103727177&sfdr_ptcid=31591_617_495141755&sfdr_hash=16cc81e0e522b4c961daa757b77dd394&gad_source=4&gclid=Cj0KCQiAoae5BhCNARIsADVLzZefdr6bzPUVEQ0JmaxiJpcAtwZ6ivmIP-kn5nLtIMbucxsIEWh0T1IaAgwnEALw_wcB

 

Trade Professional VSD Pump to supply water from tank to house and garden. Works really well. 

 https://www.builders.co.za/Water-Tanks-and-Filtration/Water-Storage/Water-Tank-Pumps/Trade-Professional-1-2HP-VSD-Intelligent-Inverter-Jet-Water-Pump-900-W-nbsp--MCOP1481/p/000000000850004992?gad_source=1&gclid=Cj0KCQiAoae5BhCNARIsADVLzZfmkeTJLzhmDQ6H7_NQSfl32w6Xehcm2mFGxDy3eIKqAoPkMevTVtcaAlYXEALw_wcB&region_id=ZAGP00

 

 

 

 

Hi Pieter, 

 

Thank you very much for the informative reply. 

 

Could you perhaps help with a wiring diagram of the float switch with the relay and sonof?  

13 minutes ago, Carl Anthony said:

Hey Oelof,

 

I dont disagree with anyone guess it comes down to your preference as well.

Having an above ground tank for storage will be beneficial as you will be able to have better control over usage. Having it pump directly from the hole to the house could be tricky unless your recovery rate on the hole is crazy high.

So even in the dry season when the recovery rate on the inevitably becomes longer, you will be safe knowing that your tank is full.

VSD pump for the win in my opinion, I will soon be upgrading to the DAB EsyBox Mini. I currently have a Hurricane booster pump and when you open the tap the pump is at full tilt whether you open the tap 5% or 100%…its a 1.1kw pump but pulls like 1.5-1.7kw when its on. With a VSD they are more efficient where the power consumption and flow rate adjusts accordingly to the demand you place when opening a tap…so its also more gentle on your inverter/s…it not heavy metal from the first second 🤣

I have a 0.55kw borehole pump from Hurricane Pumps as well, the tank has a float switch and will only switch the borehole pump on if the water drops below the level you set it at. Same as @Pieter v D. But at the moment its dry season so I am manually having to pump from the hole…so I will also be looking at using a Sonoff basic to control the borehole pump with more ease and also prevent the pump from being on when the hole is in recovery. During the wet season I had no issue tank would top up thoughout the day.

 

Good luck with the drilling, hope you used a specialist to pinpoint the drill location for you? Oh and DEFINITELY get a clean up crew as part of the process…

Thanks Carl,

 

Ive had someone come through to look for water, found a few nice spots. I am probably going to get a second opinion as well. 

On 2024/10/23 at 3:30 PM, Oelof said:

drilling a Borehole.

Is the hole already drilled? If not then there is spesific questions you need to be asking remember this is a lifetime investment and it needs to be done correctly first time around. Drilling a borehole is not a simple task. If the borehole is not yet drilled ask these questions to the drilling contractor.

1.What is the estimated depth of drilling?
2.What is the borehole construction & how much casing is needed?
3.What type of geology will be drilled through?
4.What method will be used to drill to this depth, and can it go deeper if necessary?
5.What is the expected cost to drill this borehole? (Important note – the answers to questions 3 and 4 can have a dramatic effect on the price!)
6.Can the driller develop (i.e. flush with compressed air) the borehole after drilling and for how long?

 7.What type of aquifer was identified by a geologist?

Submersible pump can only be identified (head capacity) after the depth of the borehole is established.

Edited November 8, 20241 yr by Derek3
Paragraph numbering

On 2024/11/08 at 7:42 PM, Oelof said:

Could you perhaps help with a wiring diagram of the float switch with the relay and sonof?  

 

Wiring diagrams is not something I do on a day to day basis - please excuse amateurish sketch attached here. 

The tank level switch closes the circuit when water is below its level - opens when tank is full. The level switch can be flipped up or down depending on your preference - creating a NO (normally open) or NC (normally closed) switch - quite nifty.    

The way mine is wired is so that relay will be switched off when the signal wire to level switch is damaged or opened - its over 50 m from relay to tank. You can wire it the other way around as well - switch NO and then use the NO contact on the 220V side of the relay.  

The relay and Sonoff switch is in series - but the Sonoff needs to be closest to the breaker otherwise you will have connectivity issues as it will switch on and off all the time. 

Edited November 12, 20241 yr by Pieter v D

Thank you very much Pieter,  this helps alot.