I have other posts about replacing my deep well jet pump where I have
no details on the actual depth of the foot valve even though the well
is 175 feet deep. Does anyone have information
on a McDonald pump installed about 1972..the model number on the pump
itself is 4651..the motor is 1/2 hp..It would be great if I could find
out to what depth this model was capable of
pumping. It seems that this unit was part of the 4600 series ..
I will call the company if I see no replies..maybe there are archives
at the company.
What are you trying to do? Replace the pump? If so, buy another 1/2 hp or
3/4 hp and you are in business. Most well pumps are good to over 300 feet.
Check out the specs here to 350 feet
You'll know how far down it was once you pull the pump since you can measure
Or do you have that pump and want to use it?
On Sep 9, 2:01 pm, firstname.lastname@example.org wrote:
The question is how much 'head' do you need to pump. Depth of well
has almost zip to do with it. The 'head' is measured from the level
of normal drawdown. i.e., a pump in a 150 ft well and set at 135 ft
is meaningless to calculate 'head'. If water level after drawdown is
say 40 ft from top of well, then you only need 40 ft (plus a bit for
pipe restrictions, additional height in house, etc.) of head.
I found this while surfing,,agree it is academic..The example seems
extreme to me but what do I know?
So what sized pump could accomplish this task in the example?
To size a well pump you need to know 6 things.
(1) The house pressure required.
(2) How deep is the pump to be set.
(3) The standing water level (static water level).
(4) The well recovery rate in gallons per minute
(5) How many stories the water is to be pumped.
(6) House usage in gallons per minute required.
When you know the values of the 6 parameters listed above you can then
easily figure the correct pump size. There are other factors involved
but the 6 listed above are the most important.
We will figure an example well assuming we want to have 60 PSI, the
well is drilled 200 feet, the well recovery rate is 7 gallons per
minute, the house is 2 stories high, the well is drilled 100 feet from
the house, the static water level is 25 feet and the house has 2
First step: take the house pressure needed and multiply it by 2.31.
This will determine the head pressure needed for the house.
For our example we will use 60 PSI.
60 times 2.31 = 138.6 feet of head needed for the 60-PSI at the house.
Second step: figure out the depth you will be setting the pump.
Most pumps are set 20 feet off the bottom of the well.
Sometimes the pump is set higher than 20 feet off the bottom if the
static (standing) water height is close to the surface (a well with a
6-inch casing contains 1.347 gallons of water per foot).
For our example we will use 200 feet.
200 - 20 (feet off the bottom) = 180 feet of head.
Third step: add up how many stories you will be pumping the water up
For our example we will figure 2 floors at 10 feet per floor.
2 X 10 = 20 feet of head.
Fourth step: figure the head loss in the 1-inch piping from the well
to the pressure tank. This is assuming the pressure tank is in the
For every 125 feet of 1-inch pipe there is 6 feet of head.
For our example we will use 100 feet from the well to the house.
100 divided 125 = .8
.8 X 6 = 4.8 feet
Fifth step: add all of the sums of the first four steps together.
This total will give you the amount of head in feet the pump will need
Step (1) = 138.6 feet of head
Step (2) = 180 feet of head
Step (3) = 20 feet of head
Step (4) = 4.8 feet of head
138.6 + 180 + 20 + 4.8 = 343.4
On Sep 11, 3:34 am, email@example.com wrote:
Thanks, I had never seen it laid out like that.
I do have a few probems with it.
"First step" He uses 2.31 ft. The 'theoretical' figure for pressure
per foot is 2.46. I assumed he was making allowance for pipe friction
but later he adjusts for it. He may be allowing for pump efficiency.
Then he doesn't make any allowance for normal draw down. Of course
they may always assume the drawdown is to pump level so that is
How much pump? I didn't do the calculations but with the final
figure, you then go to the pump company and look at pump
In your case, I think you said the current one is 1/2 hp. That alone
doesn't really tell you what the pump specs are but it does give a
ballpark estimate of size needed. The pump name and the tag on it
should lead you to the manufacturer site where the specs should be
Were it me with the same problems and I had to replace the pump, I
would up it to a 3/4hp, again after checking specs.
That is the reason for my first post in this thread.
My current pumps specs..I don't have them..The installer was suppose
to fill in the details but didn't..
I was hoping someone from the past would remember.No response from
the company via email..will wait a bit longer
before I call Mcdonald..
If it's a so-called 'rigid pipe' system, which is possible from that era,
you will have a devil of a time finding parts for it.
Your well will be straight outside from where the pipe exits, probably not
far, but there's no telling. If you're lucky enough to have an outside tap
on the same wall, use that to calculate the depth of the water pipe,
otherwise just measure carefully from some other point of reference.
After that it's a matter of careful digging until you find the well itself.
You may want to consider replacing your jet system with a submersible rather
than another jet.
If you get another half HP of the same or similar type pump, it should be
able to push the same or similar amount of water at the same or similar PSI
and head. If you are concerned get a slightly larger HP
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