Pump for well in house and above ground level 1

[JerinG]

I have a 16 m deep 4" well beside my house that will be used for energy source for house warming with heat pump. Usual way to do it is to use a submersible well pump in the bottom of the well. I also have a second well that is used to return water after it was cooled, but this one is only 3 m deep and is used to drain water back to underground. Level of water in first well is around 3 m below surface and in the second one around 2 m below surface. Second one also gets higher when pumping water from the first one, because the water drains slower to ground.

My question is if I can use a pump in house and above ground level if I have a vertical check valve in the start of the water pipe in the first well and the pipe end outlet in the second well is always sumberged under water? Pump should suck water for about 1 m height (changes a bit during the year and with use), everything else are pressure losses in the system. I would like to do this, because the pump in house will be easier accessible and easier to service. What kind of pump would be appropriate?

 

[LittleInch]

Can you use an above ground pump - yes providing the level in your feed well doesn't get lower than 6-7m difference from the pump.

But you either need a self priming pump or be able to create a low pressure in the pipework to flood the pump inlet. After that though, providing the NRV holds you should be good to use a simple centrifugal pump.

Or you can fill the inlet pipe with water from the top and vent off the air if your NRV is good enough and then turn the pump on.

Creating the low pressure sufficient to draw 3m or more of water up the well is the key. Most wet / dry hoovers quote 20kPa vacuum but it's not clear if that's 20 kPa absolute or 20 differential.

20 differential won't work, but do a simple test.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[JerinG]

Hey LittleInch. I know that it is possible to use the well suction pump as something like this: 1.6 HP 1200W SHALLOW WELL GARDEN PUMP. I use one already, but for other purpouses and it doesn't run a lot, so power up to 1,5 kW is not a problem, because short running times still mean a small amount of electrical energy used. I also have non return valve at the bottom and it holds 4,5 bar pressure with no problem or apparent leaks.

That's why I want to design a similar system with pump inlet pipe always flooded, because I don't want to draw the water for 3 m or some more at every pump start. That will be possible with a non return valve. For the first start or staritng the pump when the pipes were empty, I just need a t-joint from which I will flood the inlet pipe for pump. Return pipe on outlet also helps to pump water. As I know pump needs to make a head of height difference from feed well to return well (let's say that's maximum possible 3 m) and all pipe pressure losses.

As I said, smallest possible electrical power is wanted (with some saftey factor of course), that's why a normal centrifugal pump would probably be ideal, something like this: Grundfos circulator pumps. But I still have no experience how would this kind of pump perform if it has to lift water for 3 m instead of push it for 3 m. I'm not from this engineering area, so I hope my choice of words is good.

 

[itsmoked]

You realize there are a bunch of down hole pumps that easily fit 4" wells and cost less than $150? Using a down-hole pump in less than 52 feet is pretty trivial.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[JerinG]

Yes, I realize that and I'm already using it for different purpouses. I came here to get some information about the option I asked, that is pump above ground and in house. That option is easier accesible and serviceable. If I get some info, then I will decide between both...

 

[LittleInch]

Centrifugal pumps work on differential head, so a pump with say 10m head could be -3 inlet, 7m out.

The difficulty for small domestic pumps is finding data on whether they will operate well in a slight vacuum condition long term as it's not how they work most of the time. Try it and see is likely to be your only way.

Non return valves though are notorious for not sealing 100% over the long term so your initial lift pump may need to be used more as time goes on.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[JerinG]

Ok. I understand. So pump with 15 m head can draw water for 3 m height and pump it to 12 m height or pump through cca. 12 m pressure losses after the pump?

What are all the negative consequences for centrifugal pump working in vacuum condition? Just cavitation or anything else?

For return valve leaking I was thinking about a pressurized conection that will flood inlet pipe when pump starts or before pump starts. This could be controlled with simple EM valve. The valve will open and close before pump starts. The result will be always flooded inlet pipe and pump will never start with empty inlet pipe.

 

[LittleInch]

"So pump with 15 m head can draw water for 3 m height and pump it to 12 m height or pump through cca. 12 m pressure losses after the pump?" - That's about right

"What are all the negative consequences for centrifugal pump working in vacuum condition? Just cavitation or anything else?"
Cavitation is one, but also the pump shaft seals might not be suitable and hence air would enter the seals as they are expecting positive pressure. Running dry for any length of time doesn't tend to do them any good either.

Flooding the inlet pipe should allow the pump to start and generate flow. Might need a vent line somewhere as well or a bypass around the pump to flow into the disposal well to flush out air pockets or a high point automatic vent.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[JerinG]

Ok. That's good for now, enough information for home use . Now my last question. Which manufacturer would you recommend? You are probably from US, LittleInch, but it doesn't matter. Just to get something I can research on.