Wrong Pump

[Bob1000]

I have a water boosting system as follows:-
1hp self priming pump connected to the city mains
Pressure tank 24 Liter capacity with air pressure 28psi
Pressure switch set to 40/60 psi
The system works fine most of the time when the city pressure is around 20psi but sometimes I notice that the pump can not switch itself off obviously because it can not build up pressure up to 60psi for the pressure switch to cut off , that happens usually during the peak time when the city pressure is relatively lower.
I do need the house pressure to be in the range of 40/60 and I can not reduce the setting to 30/50 psi as it would be very low for the shower and would make the pump go on and off during the shower WHEN THE CITY PRESSURE BECOMES HIGHER IN THE EVENING TIME.

I have been advised here that I got the wrong type of pump and I should have bought a multistage pump which can build up high pressure ...
The question now is:-
IN STEAD OF BUYING ANOTHER EXPENSIVE MULTISTAGE PUMP ( Not even available in my area for the time being) , CAN I BUY ANOTHER SMALLER PUMP AND CONNECT IT IN SERIES TO THE EXISTINFG PUMP TO HELP IT BUILDING THE PRESSURE TO 60PSI ?
Thanks for every one in advance!

 

[Mike Swearingen]

I'm not a pump and well pro, just a long-time DIYer, but I believe that the answer to your question is yes.
Check out:
www.IrrigationTutorials.com for more detailed info.
Good luck.
Mike

 

[Sponsor]

 

[Bob1000]

I'm not a pump and well pro, just a long-time DIYer, but I believe that the answer to your question is yes.
Check out:
www.IrrigationTutorials.com for more detailed info.
Good luck.
Mike

Thank you very much , that was a great help for beginners

 

[Wet_Boots]

How about working up some actual flow and pressure numbers? That would help you select a good pump for the job. One pump. Not two. One shallow-well jet pump. Employed as a booster, they can add more than 60 psi to your water pressure. Shallow-well jet pumps are available everywhere good pumps are sold.

 

[Speedbump]

You apparently bought the wrong pump in the first place. One horse shallow well jet's will easily build 60 psi with a 20 lb flooded suction. A multistage isn't necessary, the right pump is.

bob...

 

[Bob1000]

To Wetboots with thanks

How about working up some actual flow and pressure numbers? That would help you select a good pump for the job. One pump. Not two. One shallow-well jet pump. Employed as a booster, they can add more than 60 psi to your water pressure. Shallow-well jet pumps are available everywhere good pumps are sold.

The city pressure can go down to less than 10psi and the actual flow that would be needed in the house during the peak (shower& other applications) would be say 0,5cubic meter / hour
I approached some pump sellers .... 2 HP multistage ( 2 stages only) would generate 6bars = 88psi , that would be ok to have some more power moe than the 60psi that I want ...just to let the pump work comfortably not in its max strength
What do you all think?

 

[Wet_Boots]

If you mean a flow of one-half cubic foot per minute, that would be less than four gallons per minute, and that would let you use something like a Goulds J5SH, which can add the needed 60 psi to a flow of around 5 gpm, so there's reserve capacity there. The J5SH is a higher-pressure version of their standard pump. Some other manufacturers have similar product lines.

http://www.goulds.com/pdf/BJS+.pdf

 

[Speedbump]

You are looking at pumps that are more horsepower than you need. A multistage 2hp can also pump around 40 gpm. I don't think you need that for your home. A single stage 1/2hp jet pump can produce enough water and pressure to do the job.

bob...

 

[Alternety]

I gotta believe the poster knows the difference between a cubic meter and a cubic foot. It would be a bit less than 18 cubic ft/hr. About 135 gph. Or 2.25 gpm. That feels rather low.

 

[Wet_Boots]

Ahhhh, cubic meter. I knew something wasn't jibing while I was looking up pump curves. 2.2 gpm is rather low for a flow rate.

 

[Bob1000]

Variable city pressure

Another problem came up now, the city pressure varies dramatically from 10psi or even less to 25psi so I can not set the pressure switch to a constant value
i.e. If I set it to 20/40 , the pump does not start at all and I had a poor shower !
If I set it to 30/50 or 40/60 , the pump can not switch itself off during the time when the city pressure is low
The question now is ...IF I REPLACE THIS PUMP BY THE NEW SUGGESTED SHALLOW WELL JET PUMP , HOW I CAN OVERCOME THE PROBLEM OF VARIABLE CITY PRESSURE ?

 

[Wet_Boots]

Now you're inventing non-existent problems, which is about the time I begin to wonder if you don't need to hire a competent professional. Any of the Goulds jet pumps on the webpage I linked can develop 60 psi from a bucket of water, let alone from a pipe under pressure. All that changes is the operating efficiency of the pump. You still get to use a 40-60 switch setting.

 

[Speedbump]

You can get rid of the pressure switch and tank and install a simple Flow Switch

You could also install a Cycle Stop Valve if you want to control the pressure and have it remain constant.

bob...

 

[Bob1000]

water hummer

You can get rid of the pressure switch and tank and install a simple Flow Switch

You could also install a Cycle Stop Valve if you want to control the pressure and have it remain constant.

bob...

I used a flow switch ( FLUOMAC) before but it caused problems of water hummering and shocks at the begining of opening water taps , i.e. when you open the tap you find poor water pressure ( as you know the water is not a comprissible material) so you keep opening it more then suddenly the pump starts by the flow switch and cause water hummer specially if you are a guest or dont know the water system in use
I tried to use a 24L bladder pressure tank to have some momentary pressure in the line before the pump starts but for some reasion it did not work !
Any comments?

 

[Bob1000]

cycling !

Now you're inventing non-existent problems, which is about the time I begin to wonder if you don't need to hire a competent professional. Any of the Goulds jet pumps on the webpage I linked can develop 60 psi from a bucket of water, let alone from a pipe under pressure. All that changes is the operating efficiency of the pump. You still get to use a 40-60 switch setting.

I do understand that the new pump would develop 60 psi in excess to the existing city pressure in th pipe , but when the city pressure is high the pump cycles during th shower and smetimes does not start at all if the pressure switch is set to 30/50 unless I open another tap then it works for a minute and off again and cause cold water shocks during th shower .
I will install the new pump first with 40/60 setting or even 50/70 and the pump u suggested would give 88psi , then see if I would need a CSV or not
Any comments?

 

[Wet_Boots]

So you now mention, for the first time, that you want constant higher pressure. Different animal. One might just add a lot of pressure tanks to the setup, to slow down the rise and fall of pressure. A CSV will cost less, but it isn't giving you dead-constant pressure, because it has to allow a small amount of water to pass through it to shut off the pressure switch. Use a small tank with a CSV, and you will reach its stable operating point sooner than with a large tank.

And for the purists, one could always construct a boosted water supply with a 60/80 psi range, then run the supply through a pressure reducing valve to get a constant pressure. Unless you have a (expensive) pilot-operated PRV, figure on a 20 psi drop through a standard PRV, at a minimum.

 

[Speedbump]

If you do what I suggested, you will get rid of your water hammer by use of the CSV and you will have instant pressure with the use of the flow switch.

bob...