Installing submersible pump

[Stevemercer]

I'm looking for any advice or helpful hints in installing a submersible pump. We have a 5 inch well drilled to 60 metres. The contractor says there is good water. I brought a Franklin 1 HP submerged motor (plus surface control box) connected to a Schaefer pump with 4 cm outlet. I just want to pump water to the surface and then run it for 4 or 5 metres along the ground to empty into a pond. I'll manually run the pump to top up the pond on occasions. The system does not need to be pressurised. I'll get help with the installation, but wanted to make sure I was on the right track.

I intend to use fishing line/sinker to confirm the depth of the well, and then a float to get the water level. The pump came with 40 metres of cable so I guess I'll try this depth initially assuming there is at least 10 metres of water above the pump? (Question 1)

Question 2 - Should I use steel cable or rope to lower and hold the the pump in the borehole?

Question 3 - Can I just use 4 cm PVC pipe all the way from the pump to the surface, and then to the pond?

Question 4 - Do I need any check valves to maintain pressure in the outlet circuit when the pump is off? I'm assuming no, for my application,

Question 5 - I'm assuming that I can run the pump for a few hours and then measure the borehole water level to get an idea of the drawdown and if I need to lower the pump some more?.

Question 6 - I'm hoping for at least 20 litres per minute. Does this seem reasonable?

Thanks for any assistance.

[CharlieH]

Moving to DIY Housing forum

[ThaiKneeTim]

I intend to use fishing line/sinker to confirm the depth of the well, and then a float to get the water level. The pump came with 40 metres of cable so I guess I'll try this depth initially assuming there is at least 10 metres of water above the pump? (Question 1)

A: Difficult as there are too many variables that need to be considered. Geology, rating of pump, etc.

Question 2 - Should I use steel cable or rope to lower and hold the the pump in the borehole?

Stainless steel cable would be best.

Question 3 - Can I just use 4 cm PVC pipe all the way from the pump to the surface, and then to the pond?

Not ideal, PVC has a tendency to shatter easily. Galvanised pipe would be stronger and also negate the need for the support cable or rope.

Question 4 - Do I need any check valves to maintain pressure in the outlet circuit when the pump is off? I'm assuming no, for my application,

Yes, a check valve, or 'Non Return Valve' would keep the riser pipe full, saving time and energy refilling it every time you run the pump. A check valve would also prevent siphoning and potentially polluting the groundwater.

Question 5 - I'm assuming that I can run the pump for a few hours and then measure the borehole water level to get an idea of the drawdown and if I need to lower the pump some more?.

Check the drawdown sooner rather than later, a burnt out pump motor isn't worth the risk. After an hour or two you will probably have an idea of drawdown and should be able to roughly calculate the remaining time.

Question 6 - I'm hoping for at least 20 litres per minute. Does this seem reasonable?

Hard to say without knowing the rating and type of pump. A good pump should give you head information. Forty metres of cable doesn't necessarily mean 40 metre head.

A good multistage borehole pump would come with a double check valve and would be designed for a high head whereas a puddle pump wouldn't.

[surangw]

be sure there is a gfi installed at the first power connection point

[Stevemercer]

Thanks ThaiKnee and Surangw. Your advice is much appreciated.

[Crossy]

be sure there is a gfi installed at the first power connection point

They're called RCD or RCBO here, start at about 500 Baht complete with little plastic box for it to live in