PRV question after adding well storage tank and booster pump

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Roadrunner255

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Hello,
We had a storage tank and Grundfos scala 1 booster pump (non adjustable for pressure) added to our well and I noticed water pressure in the house jumped to 85psi when the the booster pump is activated (pressure bleeds down when no water demand).

While we like the pressure I am concerned about any potential damage to plumping or appliances.

Would a prv be appropriate installed after the booster pump?

Our well has very hard water 120 gr and 1 gr iron.

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Reach4

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Are you saying that the well pump fills the open tank, and the Grundfos scala 1 booster pump alone serves as the pressure pump to raise the ~zero pressure in the storage tank to the pressure in the house plumbing?
 

LLigetfa

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85 PSI is only 5 PSI above the recommended max and since it is not constant, I would not be too worried about detrimentally affecting the plumbing and fixtures.
 

Valveman

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Sorry for the delay. But that pump should be capable of a pressure setting between 22 and 80 PSI. If it is just running at 80 PSI all the time it is not working and should be sent back for a warranty. You do not need a PRV if the pump is working. Of course replacing often is the most important feature of that Scala type pump. So, you would be much better off with a normal long lasting shallow well jet pump and PK1A to control it. A J15S and a PK1A would give much better and controlled pressure while making the pump last many times longer than it should and many many times longer than any VFD type pump like the Scala. They make it sound really good, so you should know it is not.

Shallow Well Pump with PK1A.png
 

Roadrunner255

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Are you saying that the well pump fills the open tank, and the Grundfos scala 1 booster pump alone serves as the pressure pump to raise the ~zero pressure in the storage tank to the pressure in the house plumbing?

Yes, storage tank and booster pump sit about 10 feet higher than the house.

The Scala 1 5-55 is not adjustable, the Scala 2 is.
5 Max. flow rate [m3/h]
55 Max. head [m]
Pump starts pumping when the flow is higher than Qmin (1.5 l/min).
Thanks for the info, will look into that option!
 

Valveman

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Are you saying that the well pump fills the open tank, and the Grundfos scala 1 booster pump alone serves as the pressure pump to raise the ~zero pressure in the storage tank to the pressure in the house plumbing?

Yes, storage tank and booster pump sit about 10 feet higher than the house.

The Scala 1 5-55 is not adjustable, the Scala 2 is.
5 Max. flow rate [m3/h]
55 Max. head [m]
Pump starts pumping when the flow is higher than Qmin (1.5 l/min).
Thanks for the info, will look into that option!
Yes, the well pump should fill the cistern (open tank) and the Scala draws water at zero pressure from the cistern and builds pressure for the house.

Cistern Storage Tank with JET Booster Pump (12).png
 

Valveman

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The Scala 1 5-55 is not adjustable, the Scala 2 is.
5 Max. flow rate [m3/h]
55 Max. head [m]
Pump starts pumping when the flow is higher than Qmin (1.5 l/min).
Thanks for the info, will look into that option!
You just taught me something new. I didn't know Grundfos made a "non-variable speed" Scala1. Can't find the RPM in any of the cut sheets, but it is not variable according to the curve. https://assets.freshwatersystems.com/image/upload/s--jRziRFrI--/uzpwygn3mpwhh3tgnflb.pdf

It is a single speed, multi-stage centrifugal, with a water lubricated and cooled motor. It is a little pricy but I find it VERY interesting. One of the main problems with the Scala2 is the complications and problems from the variable speed part. That Scala1, just from being a simple single speed type pump must have many fewer problems than the variable speed Scala2. The only problem is the non-controllability of the pressure and flow. Which Lol, I think I have the answer for. The curve for the Scala1 shows it has a very good drop in horsepower as the flow is restricted. Adding a Cycle Stop Valve and or a PK1A kit to that pump should make it work better than the variable speed model.

This curve also shows it working down to zero GPM and 180' of head, which it can't do for very long without getting hot. The CSV would only let it work down to 1 GPM and everything should stay nice and cool at only 600 watts.

Scala1 5-55 curve.png
 
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Valveman

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I would show a Scala1 with a PK1A kit but Grundfos wouldn't like that. Had a lawyer make me remove any pictures with one of their pumps on it. Too bad for them. I think the PK1A will make the Scala one work just as well as a jet pump with a PK1A like this.

Shallow Well Pump with PK1A.png
 
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