low water pressure

[moideen]

I have 3 floor building. There is not enough water pressure in taps and bath rooms. the existing 2 set booster pump is GRUNDFOS CR 20-02. Water flow is 92 gallon and 72ft head. the system vet old, I wand upgrade the system with higher capacity. I got proposal with LOWARA pump, with same flow rate and 144 feet head. MODEL SV-22 04. What you think, does it work and solve the problem? Pipe size 2inch ppr.

thanks
moideen

 

[Artisi]

What pressure is available now at your high point, was there sufficient pressure when firstly installed and run - have you checked the discharge pressure at the pump?
In theory the Lowara should do the job and give higher flow and pressure from the system.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[moideen]

Discharge side 2.5 bar. My question is if increase only the pump head with same previous flow rate, does it increase the pressure?

 

[bimr]

The Grundfos pump should have come close to satisfying your requirements for pressure on the 3rd floor.

You should check the pressure coming into the building, the pressure on the discharge of the pump, and the pressure on the 3rd floor prior to purchasing a new pump.

Yes, it should provide the same flow at a higher pressure.

 

[1gibson]

Is this new (Never Ever Worked) or a few years old?

 

[LittleInch]

Is your problem pressure or flow?

If no other outlets are open, do you have enough pressure and flow at the taps on the top floor?

If yes, then I suspect you have too much flow going on normally and you need to add flow capacity as well as pressure.

Maybe your pump is old and not able to supply all the outlets?

Mind you what I assume is 92 US gallons per minute is 350 litres per minute. This seems quite a lot, but how many flats / units etc does it feed?

You need to work out what your demand is before you decide on the size of a new pump.

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

 

[cvg]

72 feet head is barely adequate for static conditions and with any sort of demand and headloss will have barely any pressure at the third floor. the new pump should provide adequate pressure. without knowing the demand, impossible to tell if it provides adequate flow rate. you would need to have a fixture count for the building.

 

[moideen]

LittleInch: problem is pressure. If suppose close the all tap, it do not build up the pressure on discharge side gauge. . I don’t know the history of the system. I planned to upgrade the system instead of repairing. If the repairing not success, I will lose its repairing cost. The existing pump head is 72 and flow rate 92 us gallon. I got a proposal from contractor for new system. They have increased the head (144 ft) only but the flow rate is same (92). My idea is to increase the flow along with head. if suppose there over flow can be controlled and avoid the risk.

 

[moideen]

cvg: i want to know more about 'fixture count'.can you expalin

 

[Artisi]

What is the inlet pressure to the pump, has this pressure changed since the initial installation?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[cvg]

fixture count = number of sinks, toilets, showers, etc.

http://www.amwater.com/files/2012 fix ct data sht.pdf

 

[1gibson]

Just be careful not to overdo it. If the existing pumps are worn out, performance will be lower than it was originally. So if you "double" the original new pump specs, you might get "triple" what you are experiencing now. I'm being deliberately vague, just trying to illustrate the general idea that what you have down probably does not represent the full original pump performance.

 

[bimr]

You would be better served if you analyzed the system prior to spending money. If you don't know what the problem is, then you may waste your time.

Review the upload below and you should be able to design the system.

Note that this is a webinar coming on this application:

https://vts.inxpo.com/scripts/Serve...5-ACA6-3C55BDC128FA&AffiliateData=PM202email2

 

[moideen]

THANKS TO ALL YOUR RESPONSES, I WILL RECHECK THE SYSTEM AS YOU ADVISED

 

[moideen]

CVG: is the fixture value is in gpm or ltr?

 

[bimr]

The fixture unit method is in gpm.

https://www.cedengineering.com/userfiles/Potable Water Plumbing.pdf

 

[moideen]

please see the attached file of number of fixtures and required gpm. i think have done some mistake in this calculation, because the gpm shows higher value.the fixture numbers are correct.

thanks
moideen

 

[bimr]

That is not correct. Use the method posted on 20 Jan 16.

 

[moideen]

OK, this is lengthy document ced engineering, if you have particular paper please upload here, or i will check and extract it.

 

[cvg]

look at table 2