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YarekBalear · Sep 13, 2009, 03:16 AM

Tried browsing for an answer to my question and while there was relevant info, it didn't directly answer it, so here goes...

My house and my direct neighbor's house are fed by a shared pump from a well about 400 meters below our houses. Each of us have a header tank, our sits in their garage and we have an additional local pump to feed our hot water header tank. Our cold water is gravity fed from the tank in their garage. They have their own tanks that gravity feeds their whole house. When either of us demands water in our tanks controlled through float switches, the pump switches on and control valves direct whether water goes to either or both tanks.

The system now has problems (faulty control valves on both tanks and faulty electrical switch box) and while consulting with a neighbor he recommended us changing to a pressurized system. The idea being this would remove the need for our header tank in the neighbor's garage (they would retain their tank based system) and provide us with improved water pressure throughout our property.

So onto my questions. If we have a shared pump, with pressurized cylinder and no header tank, would the pump need to switch on every time we turned on a tap? Would that create any increased reliability issues for the pump? Does the pressure cylinder need to be beside the pump or can it be located 300-400 metres away from the pump (i.e. next to our houses) for easier monitoring/control/maintenance?

Many thanks in advance :)

speedball1 · Sep 13, 2009, 05:26 AM

Where are you located?

So onto my questions. If we have a shared pump, with pressurized cylinder and no header tank, would the pump need to switch on every time we turned on a tap?

No! Your pressure tank would maintain constant pressure as you turned on a tap.

Would that create any increased reliability issues for the pump?

No!

Does the pressure cylinder need to be beside the pump or can it be located 300-400 metres away

That question's been asked before. The concenses is that, while there may be a little line loss due to friction the loss wouldn't be enough to impede operation so the 3 or 400 meter pipe would simply become a extension of the pressure tank. Good luck, Tom

YarekBalear · Sep 13, 2009, 05:35 AM

Thanks for the answers Tom. I saw the consensus on the pipe distance, but wasn't sure if the answer on that was final. Makes sense to me though.

On the pump issue, am I correct then in assuming that because the system is pressurised from the well - drawing from it through opening a tap simply draws at the same rate from the well without pumping? I'm surprised if that's the case when the well is so far below our properties and it suggests the pump will only ever be needed to re-pressurise the system if there's a problem. Am I hearing that right?

speedball1 · Sep 13, 2009, 05:52 AM

On the pump issue, am I correct then in assuming that because the system is pressurised from the well - drawing from it through opening a tap simply draws at the same rate from the well without pumping

Are you under the impression the well's pressurized? It's not! The water you draw from your tap comes from your pressure tank and not directly from the well. The pump draws water from the well and stores it, under pressure, in a tank. There's a check valve installed so the pressure won't bleed back into the well.

the pump will only ever be needed to re-pressurise the system if there's a problem.

You almost got it right. The pump's needed to restore pressure when you draw down the pressure below a certain point and the [pump control calls for more pressure. There is no "problem" involved here.
Would you like a explanation of how a deep well pump system works? If so I'll need the type of pump that you have. Regards, Tom

YarekBalear · Sep 13, 2009, 06:04 AM

Thanks again. The pump is not submerged into the well like some I appear to hear about on here. I was also informed (perhaps incorrectly) that the pressurisation system uses air and didn't have much of a water reservoir - which would essentially mean that any meaningful amount of water taken out would cause it to use the pump. Having said all that, I'm totally new to the concept of a pressurised well system, so I clearly don't understand the mechanism clearly yet (that's why I'm bugging you guys :))

jlisenbe · Sep 13, 2009, 06:16 AM

This site has a pressure loss calculator. It shows a loss of 31# on Schedule 40 pvc (1") over a 400 meter run. That amazes me. Try it yourself.

PVC Pipe Pressure Loss Calculator

hkstroud · Sep 13, 2009, 06:31 AM

I must have done something wrong. One inch PVC at 3 gpm gave me 3.1 pressure loss.

Strange, that was Schedule 40 PVC. I did it again just to make sure. I inadvertently use Schedule 80 the second time and it came up 4.8.

speedball1 · Sep 13, 2009, 09:25 AM

Yhe only problem with this is we don't have enough information to place a line loss figure on this particular situation. Regards, tom

I'm totally new to the concept of a pressurised well system, so I clearly don't understand the mechanism clearly yet (that's why I'm bugging you guys )

Will this help? (see image)

jlisenbe · Sep 13, 2009, 11:03 AM

HK, I think I see my problem. I put in 1" pipe at 10 gpm and got a 31# loss. However, when I went to 6 gpm it was only 12#, and 5 gpm was about 9#. Evidently, the water velocity in the pipe makes a much bigger difference than I would have thought.

Going to a 2" pipe reduced the loss to next to nothing. That might be a piece of information worth remembering.