I hesitate to install another pump just to pull vacuum and save 45 seconds. That and I worry that if get any water in the vacuum pump at all I have another problem to fix. This just eases the cost of the system as I would need another float switch, and still need a solenoid valve to close off...
I did search but found no answer directly relating to my question. I think I have a better hold on what's going. However I did not search directly at eng-tips.com normally google pulls up topics on here of they relate. Could have missed it.
Also the air in the case is not a huge problem as it might nroamly be. Because of the low hight bypass valve it will separate the water from the air and return it to the intake of the pump during priming mode. Thus creating the vacuum needed for self priming. This is the same way normal self...
Actualy I will... Here's how.
I have city water plumbed into that suction side of the plumbing. On a valve by the way. The grounds crew will have a 3 way switch, on, off and maintenance/winterize. If at any time the system is turned off it will trigger a start up subroutine in the controller...
True, but lets say the leak is below the surface of the water, as much of the piping is in this case. The system will drain slowly out of that hole. once i reengage the pump and use the auto prime it will still run.
that and after the system in winterized or there is maintenance performed on...
There will be foot valves in the system, one at the base of each inlet ( I have a 2" valve that switches between two different sources.) But should they fail or there is a even a small leak anywhere in the system, all the piping would me drained.
Hmm, would over sizing the PVC help to keep the problem at a minimum.
The pump has a 1-1/2 suction and a 1-1/4 outlet.
So maybe 2" on the inlet and 1-1/2" outlet?
How much higher should the top of the p trap be? I was thinking 18" over the pump base? And also the same for the discharge just...
I think the Inverted U is cheaper then a small tank. its all done with PVC.
The 3960 just combines the weight of water (8.33) and the 33000 into on. if you use the number the answer is the same.
Here is my source
http://www.mcnallyinstitute.com/06-html/6-01.html
Thank you. you seam to be very...
ummm the 33000 is the number for 1 HP. 1HP means to move 33,000 lb/ft in 1 min.
the 8.33 is the weight of one gallon of water, roughly. the GPM is just the units of the number that precedes it. 70 GPM or gallons per min
anyways the math really doesn't matter as part of my initial question. Im...
Im having a little bit of a problem understanding how these effect my design of the pumping system.
The pump im looking at has a NPSHR of 10' at 40GPM and rises to 20' 150GPM.
What does this mean. Is this the limit that I can place the pump at above the source before I get the fluid boiling...
Also I am driving the pump with a VFD to allow me to slow the pump as needed. so every point in gained efficiency translates to a lower speed I can run the pump at before it loses its ability to pump.
After reviewing my math you are right the eff goes between 45 - 60 % but the Self priming pump works out to about 35% at best.
I used a formula I found and have kept around for some time
Power out/Power in = Pump Eff%
The formula works as this: ( I left out SG of water and just used 1 as it...
Hello,
I have never posted on this site before but find many answers to many questions i have on here.
No I have one to ask directly.
I have the need to install a pump for pond pumping and sump pumping. Im using 2" Motorized valves to select the source... not really part of my question i just...
