Borehole Advice

[Raiden2912]

Hi All,

I am in the process of sinking a borehole on my property. I have done the survey already and it looks like I will likely go 70m deep. The system I’ve been quoted on has a .075kw pump for the borehole to jojo pumping and then another 0.75kw booster pump into the house. 

my current solar system: 

16x 540w panels

1x 7.2kw OCI inverter 

2x SHOTO 5.12 SDC 10 Box 5 

I am looking for some advice on

What to look out for?

Connectivity?

any advice would be appreciated.

 

[Scorp007]

4 hours ago, Raiden2912 said:

Hi All,

I am in the process of sinking a borehole on my property. I have done the survey already and it looks like I will likely go 70m deep. The system I’ve been quoted on has a .075kw pump for the borehole to jojo pumping and then another 0.75kw booster pump into the house. 

my current solar system: 

16x 540w panels

1x 7.2kw OCI inverter 

2x SHOTO 5.12 SDC 10 Box 5 

I am looking for some advice on

What to look out for?

Connectivity?

any advice would be appreciated.

 

You should have no problem with running those 2x0.75kW motors. Just limit the use after sunset. This is to say if the borehole is only to fill the tanks then I guess you only need it during the day. 

[Robbo]

I went off grid for water about a month ago. My borehole is only 37m so you might need a bit more power in the borehole pump than me.

The main thing from my perspective was to get a VSD pump for both the borehole and the booster pumps. These types of pumps have a softer start and therefore dont put a huge strain on the inverter at startup. i.e on startup they will slowly increase their power consumption as opposed to the cheaper pumps that can pull 3x or more their rated power on startup.

This is quite a big deal in an off grid water scenario as every time you open a tap that booster pump runs, so if it spikes and then settles at 0.75kw every time you wash your hands it does put strain on the system. My DAB Esybox booster pump will pull 200W to 600W the majority of the time but can ramp up to 1.1kW if I have irrigation and shower and a tap going.

My borehole pump is a Grundfos 0.55kw VSD, again gentle startup but I also have a smart switch connected to it so that it only runs on sunny days. My tank is 5000l so I can wait a day or 2 easily if its raining.

[Raiden2912]

Thank you very informative so i am going with 2x 0.75 pumps for the Borehole and Booster (House) based on my solar system do you think i will have issues?

how has it been off grid? If you are in SA, what documents do you submit to your JHB water?

Edited May 22, 2023 by Raiden2912

[Robbo]

I'm in central Sandton but after many water pipe breaks in the area we got fed up and decided to look after ourselves. We are still connected to municipal water but have installed a manifold where we can switch between that and borehole. The installer suggested still switching over to the municipal feed for short periods over the next few month so that we slowly use less and less, that way the estimates they charge on water usage will also get smaller.

I essentially want the best of all worlds and be connected to the municipal water for an extra back up. The chance of both systems going down at the same time must be small (touch wood). So will see what CoJ does.

One other point to remember when running the borehole water into your house long term, the water quality is normally quite easily and cheaply made drinkable, however there might be more required to protect your pipes from corrosion of that water.

[Raiden2912]

19 hours ago, Scorp007 said:

You should have no problem with running those 2x0.75kW motors. Just limit the use after sunset. This is to say if the borehole is only to fill the tanks then I guess you only need it during the day. 

Thank you so much. And yes the borehole will only pump during the day to fill the jojo’s

[Bobster.]

39 minutes ago, Robbo said:

One other point to remember when running the borehole water into your house long term, the water quality is normally quite easily and cheaply made drinkable, however there might be more required to protect your pipes from corrosion of that water.

Would sacrificial anodes in the geyser(s) be enough? Or is there an anode that goes in the JoJo?

[Robbo]

9 minutes ago, Bobster. said:

Would sacrificial anodes in the geyser(s) be enough? Or is there an anode that goes in the JoJo?

I honestly dont know enough to comment on that!

In addition to the normal UV light and 3 big blue filters (5micron, charcoal and 0.5micron) we also have a ph canister and a calcite canister. Seems to do the trick.

Officially all we would need is the UV light based on the water testing results to make it potable, but the wife was not keen on that so here we are.

[Raiden2912]

Update: thank you all for the advice and direction.

so my borehole with Jojo’s system has been installed, I am now just waiting for the water analysis to come back so that I can start redirecting the water in to my house for consumption. Once this happens I can technically turn off municipal supply.
I tested both booster pumps and pump for the borehole and it’s uses around 1.2kw of power when both are running, taking into consideration the borehole pump will run during the day when the sun is up so that’s ok. The booster pump will only run when required when we open a tap, shower or run the washing machine and that goes up to 900w which I am comfortable with using the battery for that draw.

Question 1

My installer says the purifier system should be ok to protect the pipes and geyser I am not convinced of that. So I would like some advice on how I protect my piping and geyser if anyone know if I have to add something (anodes) to the Jojo’s please let me know. 

Question 2

what do I do with the municipality? Will they question the drop in usage? 
 

Will provide more updates 

Solar System

1x 7.2kw OCI Inverter

2x 5.12 SHOTO SDC10-Box 5

16x 540w Panels

Water system 

2x 5050l Jojo tanks

1x 0.75 Booster pump

1x 0.75 Pump for the Borehole

UV Light and 3 leg filtration system

70m Borehole

Edited May 27, 2023 by Raiden2912

[Robbo]

On 2023/05/27 at 8:26 AM, Raiden2912 said:

Question 1

Wait for the analysis report, there is no way the installer can guess at this stage what the level of corrosiveness will be. There should be a line with "LSI" on it and you can take it from there:

https://www.lenntech.com/calculators/langelier/index/langelier.htm

LSI (Carrier) Indication:

-2,0<-0,5  Serious corrosion

-0,5<0  Slightly corrosion but non-scale forming

LSI = 0,0  Balanced but pitting corrosion possible

0,0<0,5  Sligthly scale forming and corrosive

0,5<2  Scale forming but non corrosive

 

On 2023/05/27 at 8:26 AM, Raiden2912 said:

Question 2

Still waiting to see about mine as well, I'm using little bits still to keep the estimates lower in the future should there be a problem.

[Scorp007]

On 2023/05/22 at 12:33 PM, Bobster. said:

Would sacrificial anodes in the geyser(s) be enough? Or is there an anode that goes in the JoJo?

AFAIK the anodes are made from a metal that would corrode instead of the steel pipes or the geyser. This is the same theory used on steel pipelines. Once the anode is no longer there then the steel would corrode 

Please help out if the anode works on a different principle. 

[Raiden2912]

7 hours ago, Robbo said:

Wait for the analysis report, there is no way the installer can guess at this stage what the level of corrosiveness will be. There should be a line with "LSI" on it and you can take it from there:

https://www.lenntech.com/calculators/langelier/index/langelier.htm

LSI (Carrier) Indication:

-2,0<-0,5  Serious corrosion

-0,5<0  Slightly corrosion but non-scale forming

LSI = 0,0  Balanced but pitting corrosion possible

0,0<0,5  Sligthly scale forming and corrosive

0,5<2  Scale forming but non corrosive

 

Still waiting to see about mine as well, I'm using little bits still to keep the estimates lower in the future should there be a problem.

Thank you, Do you not have to apply for a borehole before drilling? Did you do this? 
 

https://www.joburg.org.za/departments_/Documents/Development Planning/Form 10 Borehole.pdf

[Robbo]

37 minutes ago, Raiden2912 said:

Do you not have to apply for a borehole before drilling?

My installer didnt say anything to me...

Actually I got 5 or 6 quotes and it wasn't mentioned once.

[Raiden2912]

1 hour ago, Robbo said:

My installer didnt say anything to me...

Actually I got 5 or 6 quotes and it wasn't mentioned once.

Same here 

[Raiden2912]

Update and some info. 

So my borehole has been done, I’m just waiting to the water tests to come back from the lab. The water looks fine and tastes a little like piping or metal can’t explain the taste. So will wait for the lab. 

Quick Question:

if I need to top my pool up, will the booster pump be ok to run for 3-4 hours to fill the pool? I have the 0.75kw booster pump.

[Robbo]

Not sure on your pump, but I do it on mine

[Peter Topp]

Hi Raiden2912

Just a suggestion. Before you decide to pump for a long time, make sure the borehole is filling enough to fill the borehole. You will need to know how much water your borehole actually produces. You can ask and pay to have this done or you could test this yourself by measuring the amount of water used over a specific period with an inline meter, eg, over an hour. You can also monitor the output over a long period that you want and see if the output drops. When the borehole is full (at the top of the water table) it will take time to empty the borehole to see the actual flow of water into the borehole. This is directly from the borehole pump not from the jojo. If the flow does not drop it would be great as this means that the borehole is filling faster than it can be pumped out. If the flow drops it can be measured again over a shorter period to determine the actual flow from the filling borehole. 

This is important as you can burn out your borehole pump if the borehole is pumped dry if there is no protection for this.

Also adding another comment on VSD or DC pumps. If you do not use these pumps on the output of your JoJo tank, it would be advisable to put a bladder tank in line with the pump as cheaper standard pumps do not like to be started many times over a short period (shortens the lifetime of the pump). The bladder tank stops this by setting a lower switch on pressure for starting and a higher switch off at a set pressure. Depending on the size of the tank about 50% of the size of the bladder tank must be used before the pump switches on. This prevents switching on using small amounts of water usage. 

I have done these tests on my borehole and I can only pump for 1hr15min before my borehole is empty and my flow drops.

I hope this helps.

 

[Raiden2912]

Thanks Robbo and Peter

@Peter Topp Thanks for this, really informative although a little over my head sorry. So I’ve got 2x 5050 Eco Jojo tanks that’s full. So I’m guess I will need around 3000 litres to fill my pool as I’m not filling from empty just topping it up. You’ve explained quite nicely but I suspect I need to read up more on this to learn. I know I have the float in the primary Jojo so yes if I use the 3000 litres from the one tank it would need a refill. Let me see how I’m going to conduct the testing you speak of. 
 

thanks again

[Raiden2912]

A picture might help please if possible 

[Peter Topp]

Hi Raiden2912

Seeing you have 10100 litres capacity I do not see any problems with the flow of water into the borehole as it filled the tanks. If your .75kw motor is not strong enough to pump the well so that the flow is reduced to just filling, the borehole tests I mentioned will not be able to be done with any meaningful results.

The picture you request is I suppose for a bladder tank (pressure tank) which I have attached. The pressure tank will also need the appropriate switch on the pump to work correctly. The pressure tank can also be part of the motor assembly.Pressure-Tanks-2021-V1.pdfPressure-Tanks-2021-V1.pdfPressure-Tanks-2021-V1.pdfPressure-Tanks-2021-V1.pdfPressure-Tanks-2021-V1.pdfPressure-Tanks-2021-V1.pdf

I have also attached my calculations on how I worked out my flow rate and borehole capacity.

Borehole Capacity Test 26072022.docx

Edited June 11, 2023 by Peter Topp

[Raiden2912]

This helps a ton, thank you Peter

[Sc00bs]

Hi @Raiden2912

I would suggest considering using a VSD pressure pump as it will be constantly switching on & off. Jojo make a 0.75kw one as do DAB. 

Wouldn't worry about putting a VSD on the borehole pump as it basically switches on to fill the water and then off when it is full.

I ran 4 geysers (1x3kw, 2 x 2kw X 1 x 1.5kw) with smart switches, a borehole pump and pressure pump all from my 8kw Sunsynk without any issues. 

[Peter Topp]

Hi Raidon2912

The question you asked about low municipal water use.

Water usage is split into two. Water use and sewer. So, you pay twice for the water used. If you use no municipal water, you will definitely have questions asked and, or a visit. Even if you use no water from the municipality you need to pay the sewer fee.

To overcome this, I have a parallel system and I throttle my municipal use to show some water usage.  Most of my water is used for irrigation of my garden and I can use up to 60Kl a month. Irrigation water is only partially filtered and the household water from the JoJo tank is fully filtered and tested for consumption. I irrigate directly from the borehole pump which you can view from my other posts under sustainable landscaping.

VSD pressure pumps are much better as using a pressure vessel with a standard pump needs to be checked and is like checking your car tires and is a hassle as the pressure tank needs to be empty with no water pressure when tested or pressurized. Setting the pressure switch can also be a hassle. VSD pressure pumps use less power, and the pressure can be set much easier with pump dry protection. This being said if you have the budget, and you already have a pump.

Edited June 11, 2023 by Peter Topp

[Scorp007]

On 2023/06/11 at 10:08 PM, Sc00bs said:

Hi @Raiden2912

I would suggest considering using a VSD pressure pump as it will be constantly switching on & off. Jojo make a 0.75kw one as do DAB. 

A very simple way of creating a pressure tank is to use 2-3m of 150mm diameter pipe to act as a boere pressure tank on the pump outlet. This will reduce the start and stop quite a lot. Just ensure a non return valve. is used between tank and point of use. 

A 2m piece of pipe will provide a 11L pressure tank. 

[Peter Topp]

Hi Scorp007 

How will this work? as soon as you open a tap the pressure drops it will start the pump. A pressure tank works because of the two setpoints for the start and stop of the pump from the pressure switch, as well as the 1.8bar pressure on the bladder.