Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!
Submersible Well Pump question
- Thread starter lukin1977
- Start date
LittleInch
Petroleum
The same as any other pump would behave when the inlet head reduces because of reduced inlet pressure into the pump.
A sketch would help a lot....
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
A sketch would help a lot....
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
- Thread starter
- #3
- Thread starter
- #4
LittleInch
Petroleum
All depends what your flow out is like.
All this will change is that the outlet won't have any pressure maintenance and so any small usage or leak will lower the pressure very quickly and hence the pump will start, pump for a few seconds to pressurise the system again then turn off.
Sop you pump could get a lot of starts. If your outlet opened for flow the user would get a spurt of water then nothing, then lots of water as the pump kicks in.
The accumulator with air in it smooths all of that out.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
All this will change is that the outlet won't have any pressure maintenance and so any small usage or leak will lower the pressure very quickly and hence the pump will start, pump for a few seconds to pressurise the system again then turn off.
Sop you pump could get a lot of starts. If your outlet opened for flow the user would get a spurt of water then nothing, then lots of water as the pump kicks in.
The accumulator with air in it smooths all of that out.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
- Thread starter
- #6
the pump works 24hs a day with out stopping even when nobody is using water (this is a house installation)
The pressure never reaches the cutoff pressure set at the pressure switch (4 bar). Pressure stays at around 3 bar all the time
If pressure tank has a precharged 0 bar (no air) the the pump will start and stop very often (as you said LittleInch).
I think that there is a 2nd problem here (besides no precharge at pressure tank). I am suspecting that the pump is spinning at the wrong way. Does submersible pump have spinning direction or they work the same in both ways?
The pressure never reaches the cutoff pressure set at the pressure switch (4 bar). Pressure stays at around 3 bar all the time
If pressure tank has a precharged 0 bar (no air) the the pump will start and stop very often (as you said LittleInch).
I think that there is a 2nd problem here (besides no precharge at pressure tank). I am suspecting that the pump is spinning at the wrong way. Does submersible pump have spinning direction or they work the same in both ways?
LittleInch
Petroleum
OK,
The options are:
Your pump is either spinning the wrong way ( only really possible if you have three phase supply),
Your pump is undersized for your requirement (cannot reach 3bar at no flow)
Your pressure set-point is too high ( reset to 2.5 bar?). Why is this so high? for a domestic propert you don't normally need 3 barg
Your pump has a fault
Your electric supply is the wrong voltage or frequency for the motor
Does this help?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
The options are:
Your pump is either spinning the wrong way ( only really possible if you have three phase supply),
Your pump is undersized for your requirement (cannot reach 3bar at no flow)
Your pressure set-point is too high ( reset to 2.5 bar?). Why is this so high? for a domestic propert you don't normally need 3 barg
Your pump has a fault
Your electric supply is the wrong voltage or frequency for the motor
Does this help?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
- Thread starter
- #8
yes. It helps a lot
The pump is 3 phase supply and it`s been connected a couple of days ago
The pump is not undersized. Same size of pump has been working for long time w/o any problem
Pressure value is high but this is not the problem because the pump used to reach this pressure w/o problem
Pump has a fault: dont think so. Is a new pump
Electric supply: ok
I think that it is spinning the wrong way. Tomorrow I will change rotation direction and see what happens
The pump is 3 phase supply and it`s been connected a couple of days ago
The pump is not undersized. Same size of pump has been working for long time w/o any problem
Pressure value is high but this is not the problem because the pump used to reach this pressure w/o problem
Pump has a fault: dont think so. Is a new pump
Electric supply: ok
I think that it is spinning the wrong way. Tomorrow I will change rotation direction and see what happens
LittleInch
Petroleum
Just change over one pair of the three phase wires, I think to change the rotation. Don't know how you'll see the rotation of a submersible....
Let us know how it goes. Sounds like it might be the answer - typically you'll get about 60-70% of the proper head by spinning the wrong way so you should get about 5 bar?
Double check the required voltage and frequency of the pump match the previous unit. Also just because the pump is new doesn't mean it isn't broken or has a fault. The difference between a 50htz unit and 60 htz unit is quite large.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
Let us know how it goes. Sounds like it might be the answer - typically you'll get about 60-70% of the proper head by spinning the wrong way so you should get about 5 bar?
Double check the required voltage and frequency of the pump match the previous unit. Also just because the pump is new doesn't mean it isn't broken or has a fault. The difference between a 50htz unit and 60 htz unit is quite large.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
- Thread starter
- #10
Sounds like the house I grew up in, the pressure tank would leak air, we'd have to recharge it every 6 months or so.
The whole point of the air in the tank is to provide a pressure buffer. Without the air, the instant the water is turned on at a faucet, the pressure drops enough to kick on the pump, the pump will instantly overcome the cutoff point (because the pump generally has a higher capacity than the flow out of the faucet). As long as there is any demand on the system, the pump kicks on and off every few seconds. This can burn out or overheat the motor quickly.
To address your question about the pump never reaching the 4 bar pressure, as others have said, if it's a 3 phase supply, switch any two leads, and see if that helps.
The whole point of the air in the tank is to provide a pressure buffer. Without the air, the instant the water is turned on at a faucet, the pressure drops enough to kick on the pump, the pump will instantly overcome the cutoff point (because the pump generally has a higher capacity than the flow out of the faucet). As long as there is any demand on the system, the pump kicks on and off every few seconds. This can burn out or overheat the motor quickly.
To address your question about the pump never reaching the 4 bar pressure, as others have said, if it's a 3 phase supply, switch any two leads, and see if that helps.
"this pump works 24 hrs a day"
Do you mean it runs continuously 24/7?.
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.)
Do you mean it runs continuously 24/7?.
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.)
LittleInch
Petroleum
Artisi - I think he's probably wondering why he's getting hot water from the cold tap....
It has only been installed for a couple of days so maybe hasn't burnt the motor out yet.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
It has only been installed for a couple of days so maybe hasn't burnt the motor out yet.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
You have the pressure gauge set at 4bar correct? Reset it to a bit under 3 bar and monitor the result.
Is this tank a bladder tank, ie., a diaphram between the air and the water?
A pump curve would be helpful as would contacting your local domestic water supply guy for some advice.
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.)
Is this tank a bladder tank, ie., a diaphram between the air and the water?
A pump curve would be helpful as would contacting your local domestic water supply guy for some advice.
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.)
Tenpenny:good one, please accept my sincere apologies, that of course would read better as pressure switch.
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.)
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.)
- Thread starter
- #19
I checked direction of rotation. Pump is spinning correctly
Pressure tank: Has no air at all. I have dismounted and disassembled the tank. The bladder is good
Pump works with out stopping and pressure stays at 3 bar
Bimr: I do not know the water level in the well
cvg: I didn't think about that. Thanks!
Artisis: yes 24/7
This is the tank: LS H 60
I am going to precharge the tank again, install it and see what happens
Pressure tank: Has no air at all. I have dismounted and disassembled the tank. The bladder is good
Pump works with out stopping and pressure stays at 3 bar
Bimr: I do not know the water level in the well
cvg: I didn't think about that. Thanks!
Artisis: yes 24/7
This is the tank: LS H 60
I am going to precharge the tank again, install it and see what happens
If the bladder is good, where has the air gone?
PUMP CURVE,WHERE IS IT?
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.)
PUMP CURVE,WHERE IS IT?
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.)
- Status
