I just bought a replacement jet pump for a house well. It is
supposedly self priming. The definition of self priming isn't what I
thought. It is self priming after the intake pipes and volute are
filled with water.
Self priming to me would mean that the pump could literally prime
itself after all the plumbing was hooked up. There would be no need to
fill the intake with water.
Am I wrong or is the manufacturer stretching the truth?

"Dean Hoffman" wrote in message
...
I just bought a replacement jet pump for a house well. It is supposedly
self priming. The definition of self priming isn't what I thought. It
is self priming after the intake pipes and volute are filled with water.
Self priming to me would mean that the pump could literally prime
itself after all the plumbing was hooked up. There would be no need to
fill the intake with water.
Am I wrong or is the manufacturer stretching the truth?

"Dean Hoffman" wrote in message
...
I just bought a replacement jet pump for a house well. It is supposedly
self priming. The definition of self priming isn't what I thought. It
is self priming after the intake pipes and volute are filled with water.
Self priming to me would mean that the pump could literally prime
itself after all the plumbing was hooked up. There would be no need to
fill the intake with water.
Am I wrong or is the manufacturer stretching the truth?

I thought they use to give a certain amount of "feet of head" that it would
self prime. Today manufacturers seem to spend an awful lot of time coming up
with deceptive terms to describe the power of the device

On Jan 21, 4:35*am, Dean Hoffman wrote:
* *I just bought a replacement jet pump for a house well. *It is
supposedly self priming. * The definition of self priming isn't what I
thought. *It is self priming after the intake pipes and volute are
filled with water.
* * Self priming to me would mean that the pump could literally prime
itself after all the plumbing was hooked up. *There would be no need to
fill the intake with water.
* *Am I wrong or is the manufacturer stretching the truth?

A jet pump will never be self priming. It uses part of the water to
provide the lift. No pump can lift very far. If you want a pump that
will work even when the lines have drained then get a submersible and
put it down the well.

On Jan 21, 9:35*am, Dean Hoffman wrote:
* *I just bought a replacement jet pump for a house well. *It is
supposedly self priming. * The definition of self priming isn't what I
thought. *It is self priming after the intake pipes and volute are
filled with water.
* * Self priming to me would mean that the pump could literally prime
itself after all the plumbing was hooked up. *There would be no need to
fill the intake with water.
* *Am I wrong or is the manufacturer stretching the truth?

I think it's only self priming in that you only have to prime it the
once, not every time is stopped.

On 2011-01-21, Dean Hoffman wrote:
I just bought a replacement jet pump for a house well. It is
supposedly self priming. The definition of self priming isn't what I
thought. It is self priming after the intake pipes and volute are
filled with water.
Self priming to me would mean that the pump could literally prime
itself after all the plumbing was hooked up. There would be no need to
fill the intake with water.
Am I wrong or is the manufacturer stretching the truth?

Not being familiar with your particular pump ....is it deep or
shallow?.... and jet pumps in general, but according to what I see on
wiki, a jet pump is a velocity type pump, NOT a positive displacement
pump. You need a positive displacement pump to pull a vacuum,
therefore a prime. It appears a deep jet pump sits right in the water
source, and therefore needs no prime. Perhaps that's what your
supplier is calling "self priming". Either way, sounds like you've
been conned, sorry to say.

http://en.wikipedia.org/wiki/Injector
http://en.wikipedia.org/wiki/Pump

nb

On Jan 21, 9:57*am, notbob wrote:
On 2011-01-21, Dean Hoffman wrote:

* *I just bought a replacement jet pump for a house well. *It is
supposedly self priming. * The definition of self priming isn't what I
thought. *It is self priming after the intake pipes and volute are
filled with water.
* * Self priming to me would mean that the pump could literally prime
itself after all the plumbing was hooked up. *There would be no need to
fill the intake with water.
* *Am I wrong or is the manufacturer stretching the truth?

Not being familiar with your particular pump ....is it deep or
shallow?.... and jet pumps in general, but according to what I see on
wiki, a jet pump is a velocity type pump, NOT a positive displacement
pump. *You need a positive displacement pump to pull a vacuum,
therefore a prime. *It appears a deep jet pump sits right in the water
source, and therefore needs no prime. *Perhaps that's what your
supplier is calling "self priming". *Either way, sounds like you've
been conned, sorry to say. *

http://en.wikipedia.org/wiki/Injecto....org/wiki/Pump

nb

Someone educated me on positive displacement pumps and how much they
can lift a while back. A perfect vacuum is about 32 feet of water at
sea level so that is the absolute max that you can lift with any
pump. No water pump can get anywhere close to a perfect vacuum. In
practice lifting 20 feet would be amazing.

jamesgangnc wrote the following:
On Jan 21, 9:57 am, notbob wrote:

On 2011-01-21, Dean Hoffman wrote:


I just bought a replacement jet pump for a house well. It is
supposedly self priming. The definition of self priming isn't what I
thought. It is self priming after the intake pipes and volute are
filled with water.
Self priming to me would mean that the pump could literally prime
itself after all the plumbing was hooked up. There would be no need to
fill the intake with water.
Am I wrong or is the manufacturer stretching the truth?

Not being familiar with your particular pump ....is it deep or
shallow?.... and jet pumps in general, but according to what I see on
wiki, a jet pump is a velocity type pump, NOT a positive displacement
pump. You need a positive displacement pump to pull a vacuum,
therefore a prime. It appears a deep jet pump sits right in the water
source, and therefore needs no prime. Perhaps that's what your
supplier is calling "self priming". Either way, sounds like you've
been conned, sorry to say.

http://en.wikipedia.org/wiki/Injecto....org/wiki/Pump

nb


Someone educated me on positive displacement pumps and how much they
can lift a while back. A perfect vacuum is about 32 feet of water at
sea level so that is the absolute max that you can lift with any
pump. No water pump can get anywhere close to a perfect vacuum. In
practice lifting 20 feet would be amazing.


i.e. USS Cole attack.
Portable pumps could not siphon the floodwaters out of the engine room.


"The ship's small portable pumps could not boost the water out of the
three-story-high engine room. Grasping for a crude solution,
Peterschmidt suggested cutting a hole lower down--in the side of the
ship just above the waterline. No commander relishes punching a hole in
a wounded ship, and slicing steel was dangerous. With fuel thick on the
surface of the water in the engine room, the risk of fire from a stray
spark was grave. Reluctantly, Lippold agreed to cut the hole. The
alternative, said Peterschmidt, was to "lose the ship."
An enlisted man cut the hole; the ship did not burn; the pumps were able
to get ahead of the flooding".

--

Bill - Former US Navy Metalsmith and Damage Controlman USS Salem Ca-139
In Hamptonburgh, NY
In the original Orange County. Est. 1683
To email, remove the double zeroes after @

RBM wrote:
"Dean Hoffman" wrote in message
...
I just bought a replacement jet pump for a house well. It is supposedly
self priming. The definition of self priming isn't what I thought. It
is self priming after the intake pipes and volute are filled with water.
Self priming to me would mean that the pump could literally prime
itself after all the plumbing was hooked up. There would be no need to
fill the intake with water.
Am I wrong or is the manufacturer stretching the truth?

I thought they use to give a certain amount of "feet of head" that it would
self prime. Today manufacturers seem to spend an awful lot of time coming up
with deceptive terms to describe the power of the device


There was one described that way. Other ads said self priming if
the volute was filled first. One ad claimed the pump could handle air
in the line.

notbob wrote:
On 2011-01-21, Dean Hoffman wrote:
I just bought a replacement jet pump for a house well. It is
supposedly self priming. The definition of self priming isn't what I
thought. It is self priming after the intake pipes and volute are
filled with water.
Self priming to me would mean that the pump could literally prime
itself after all the plumbing was hooked up. There would be no need to
fill the intake with water.
Am I wrong or is the manufacturer stretching the truth?

Not being familiar with your particular pump ....is it deep or
shallow?.... and jet pumps in general, but according to what I see on
wiki, a jet pump is a velocity type pump, NOT a positive displacement
pump. You need a positive displacement pump to pull a vacuum,
therefore a prime. It appears a deep jet pump sits right in the water
source, and therefore needs no prime. Perhaps that's what your
supplier is calling "self priming". Either way, sounds like you've
been conned, sorry to say.

http://en.wikipedia.org/wiki/Injector
http://en.wikipedia.org/wiki/Pump

nb


A deep jet pump has the jet at the bottom at the water intake. I don't
know how you make it work without pumping water through the down pipe to
the jet. Must be a check valve at the intake.

A shallow well jet pump has the jet attached to the pump. When the
jet/pump are primed (just at the pump, not much water) it will lift the
water out of a shallow well where the lift pipe is not full of water
(limited lift as in james' post). It might be reasonable to call this
self-priming. There is a check valve at the intake to normally keep the
lift pipe full of water.

--
bud--

On 2011-01-22, bud-- wrote:

self-priming. There is a check valve at the intake to normally keep the
lift pipe full of water.

That makes sense. The check valve keeps the pump immersed and also
provides a enough of a seal in the pipe to pull a vacuum. I can see
how a bad check valve (or flapper valve) could put the kibosh on the
whole system. Perhaps the OP has neglected this issue. We didn't get
much info from the OP other than, it don't work.

nb

notbob wrote:
On 2011-01-22, bud-- wrote:

self-priming. There is a check valve at the intake to normally keep the
lift pipe full of water.

That makes sense. The check valve keeps the pump immersed and also
provides a enough of a seal in the pipe to pull a vacuum. I can see
how a bad check valve (or flapper valve) could put the kibosh on the
whole system. Perhaps the OP has neglected this issue. We didn't get
much info from the OP other than, it don't work.

nb

I haven't actually tried it yet. Self priming to me meant no need
to fill the volute and supply lines with water before starting the pump.
The directions with the jet pump said I need to do that. So I was
wondering what "self priming" was supposed to mean.
The set up we have is similar to the one on this page:
http://tinyurl.com/5s5md7w
The well is only 25' deep. The pump and pressure tank are in the
basement.
There used to be artesian wells on this farm long ago. No need to
pump water for livestock. The irrigation wells gradually took the water
levels down so the artesian wells are history.

On Jan 22, 10:14*pm, Dean Hoffman wrote:
notbob wrote:
On 2011-01-22, bud-- wrote:

self-priming. There is a check valve at the intake to normally keep the
lift pipe full of water.

That makes sense. *The check valve keeps the pump immersed and also
provides a enough of a seal in the pipe to pull a vacuum. *I can see
how a bad check valve (or flapper valve) could put the kibosh on the
whole system. *Perhaps the OP has neglected this issue. *We didn't get
much info from the OP other than, it don't work.

nb *

* * I haven't actually tried it yet. * Self priming to me meant no need
to fill the volute and supply lines with water before starting the pump.
The directions with the jet pump said I need to do that. *So I was
wondering what "self priming" was supposed to mean.
* *The set up we have is similar to the one on this page:
* http://tinyurl.com/5s5md7w
* The well is *only 25' deep. * The pump and pressure tank are in the
basement.
* *There used to be artesian wells on this farm long ago. *No need to
pump water for livestock. *The irrigation wells gradually took the water
levels down so the artesian wells are history.

There are two basic setups possible with jet pumps. The pump is on the
surface in both cases but it's possible to have a separate "jet" or
injector down the well or alternatively in one piece with the pump on
the surface. You are on the limit for any surface installation at
25'. The theoretical maximum is is around 30'. After that, the
working bit has to be down the well.
The advantage with this set up is that the pump/motor can be got at.
The alternative is to have a submersible pump or the jet/injector
located down the well.
The "jet" has a system of venturii that enables low pressure water
circulated through it by the pump to be converted to a much smaller
amount of high pressure water.
You need a good foot valve (on the end of the pipe down the well) and
it will need to be primed just the once. After that it is "self
primng". Depending on your definition of the topic. If it isn't, you
need a new foot valve.