#Grundfos scala 2 testbericht how to#
#Grundfos scala 2 testbericht plus#

Just a note on the 32mm (black) poly pipe. No, the flow restriction from 32mm to 25mm is a separate minor calculation and there is an increase in velocity but it doesn't alter the friction losses through the larger pipe at varying lower velocities. Running 25mm to 32mm converter would add a bit of a bottleneck wouldn't it?

#Grundfos scala 2 testbericht how to#

The article below has a reasonably good explanation about pump's performance curves and how to calculate your system's flow rates.ĭoes it matter that the pump's inlet and outlet is 25mm or 1' rather than 32mm. Having a 32mm poly pipe on the suction side would cause no stress. If so, 0.5 metre head will effectively provide half the flow rate and the pump's suction side's friction loss for this guesstimated example would be about 1.5 m. If you will be drawing from a tank, you will (hopefully) have some head and a 32mm suction pipe over a straight 30m distance might require (at a guess) a 2 m head at the tank to 'prevent' friction loss on the pump's suction side. It must also be remembered that a centrifugal pump pumps the difference between the suction and discharge heads. No, water flowing through a pipe for any distance and at any velocity will generate friction losses.Ī pump also has friction loss on the suction side and it must be remembered that a pump has more power pushing water from the pump than sucking it to the pump. There is plenty of information online as to the head losses measured as equivalent pipe lengths through various sizes of fittings with different flow rates.ĭoes this mean i should be able to suck water from source 30m away without loss of pressure so long as the elevation is flat? This will intersect the head loss/working head with the flow rate.

#Grundfos scala 2 testbericht plus#

You just take the length of pipe plus all other friction losses through fittings as equivalent lengths of pipe, get the friction loss given as lost head and then compare the result with the pump's head capacity curve. Poly pipe and pvc pipe both have the same 150 roughness coefficient, you need to know this for the online calculators. Most online flow rate calculators are pretty much the same but be sure to enter the pipe's true ID and not the DN. There will be other friction loss considerations additional to the poly pipe but also remember that poly pipe is never laid perfectly straight and so a small consideration should be made for this. It is also best not to use a pressure tank with a standard pump either as you will need consistent continuous pressure with no risk of the pump cycling. There is a mention needing clarification of a safety device that prevents using a Scala2 for more than 30 minutes continuous use. This is really a new topic that should be in the Garden sub forum. It is impossible for anyone to know if there is any cause for concern if they don't know the plumbing layout and the calculations.Īs an aside, if I had an off grid house, I would have a ceiling water storage tank gravity feeding the toilet cisterns to cut down considerably on pump wear and the inevitable multiple end fixture simultaneous flow demands. The person who calculates the loading units will be able to tell you the various and varying flow rates to the different end fixtures. Your house will be off the water grid and so the pump's static head should be known before the loading units are calculated. When the pipe sizes and lengths are calculated for a new house, whoever calculates the loading units needs to contact the utility responsible for the supply of water to find out the minimum available head and everything then designed to that figure. If/when a 500 kPa pressure regulator was fitted and the water services mains pressure also reduced (which they were), the house plumbing could/would have been affected by too much friction loss for the lower hydraulic head to satisfy flow requirements. The house water supply plumbing might also have been designed for the previous 1,200 kPa maximum pressure.

The shower rose may also have been an early water saver one with mediocre characteristics.

Your old house may have corroded (restrictive) gal pipes or the mains does not supply the maximum allowed 500 kPa.which is common. The possible reason(s) for the low pressure in your current house are varied.