from the original poster:
My problem is that the pressure switch trips or
cycles on off on off on off every second when the pressure reaches
40psi. I noticed when the pump is kicking on and off every second, the
pressure gauge is jumping from 40 to 50 to 40 to 50.

see below -

"Alan Adrian" wrote in message
...
"--" wrote in message
...
FWIW - you have put a second air spring in parallel with the original
air
bladder, and by

1/total spring=1/spring1 + 1/spring2,

you lowered the total system spring constant

(and in so doing, you reduced the peak force the system now sees from
the
moving water)

Adding a second air chamber in parallel to the first air chamber had
the
same effect on the system as lowering the first tank's precharge in
order
to
lower the system spring constant.

No one here thinks that the problem is caused by the mass of water that
needs to be accelerated when the pump starts?


What you note (accelerating a mass of water) would more likely cause a
cavitation problem -
what I addressed is the already moving water (being relatively
incompressible, the water is already moving in under that one second at
start-up, since its response time is much like a steel rod connected to the
impeller) hitting the compressible air and rebounding, and that dynamic
rebound energy being added to the static pressure energy, causing a force
spike that the switch sees as misreads as static pressure- that interaction
a fairly common problem in fluid power.

That the initial surge of torque in the pump needs to get the mass of
water
between the pump and the tank in the house moving, thus the reason for the
higher pressure (seen at the tank) at switch-on?

No, there is always an initial surge of torque with a pump, even when
unloaded ( due to the resistance of the rotor and/or water-mass
accelerating). If the mass of water is too high for the pump, usually it
will either cavitate (make noise and eat impellers) or run hot at start. I
haven't seen an undersized or improperly designed pump cycle the start-up.

That moving the pressure switch to the tank end would definately solve the
problem, but that adding a snubber (the OP chose to use a 2 gallon tank)
before the mass of water would cure the problem too, and the OP didn't
have
to dig a trench that he didn't want to?


Yes, there are many physical ways to remove the symptom and stop the pump
from cycling on start. Once a change is found that works at removing the
symptom, then one should see what change in the scientific parameters the
physcial change made, so as to check if the fix added a future problem.
Occasionally a fix in one area creates a problem in another, and sometimes
the fix could have been done more cheaply and the cost of that experience
can be amortized over furture problems

If the air in the tank is going to be absorbed into the water so fast,
what
keeps normal snubbers (vertical bits of pipe in your house that stop
hammering when you shut off the taps) from filling up with water?


I don't believe I ever claimed that air was entrained in water at
residential pressures. The snubbers don't fill up with water at residential
pressures.

Al...