Pump quits pumping before pressure switch kicks off

[Marvs41]

I recently replaced pressure tank and pressure switch because tank had a ruptured bladder. Pressure switch is a 30-50 psi switch. I set tank pressure at 2psi below kick in. Contacts on pressure switch will engage at 30psi and begin pumping however it will stop pumping around 42-43 psi and the contacts on pressure switch remain engaged. after a minute or two pump begins pumping again and when it reaches 50psi contacts open and pump stops.
Another problem is if using large consumption of water pressure may drop below 30psi before pump kicks on causing drop in pressure. Any ideas?:

 

[Rancher]

after a minute or two pump begins pumping again and when it reaches 50psi contacts open and pump stops.

What kind of pump? I'm guessing the pump is not pumping as well as it should or you are running out of well water and the pump is going into thermal overload, and the internal overload switch is tripping.

Another problem is if using large consumption of water pressure may drop below 30psi before pump kicks on causing drop in pressure. Any ideas?:

Lower the bladder pressure another couple of pounds, or raise the switch cut in to 32 psi.

Rancher

 

[Sponsor]

 

[Marvs41]

Thanks for the response. The pump is a submersible pump, 1hp, make?, about 6 yrs old. Out of curiosity, I wired directly to the pump bypassed the pressure switch to see if it would still stop pumping. When I supplied power it went from 30psi to 50psi without any interuption. Would the thermal overload still work when wired direct? I am not familiar with how the thermal overload works.

I will lower the bladder pressure a couple of lbs. and see what happens.

 

[Jadnashua]

You might be running out of water in the well, or the pump is not set deep enough.

 

[Speedbump]

Be careful wiring direct, you can build enough pressure in a hurry with a 1hp pump to take out the bladder in your tank among other things. There are better ways to test a pump.

bob...

 

[mmws]

Diagnosing pressure problem

The first thing you need to do is get an amperage reading when the pump is misbehaving. The pump will many times tell you what it is disliking.
My first stab at diagnosing this without being on the job-site would be that you could be pumping the well dry or at least down to pump level allowing an airlock in the pump which will clear itself when the water level rises.
A couple of other things to check: you may have a hole in the fitting on the top of the pump letting pressure escape. The two to three minute lag would indicate the water level in the well rising back up overcoming the head loss do to the leak. This would also explain the low volume allowing your pressure to drop below 30#. A quick check for this is to turn off the pump and disconnect the union where the water line comes from the well. If you feel a vacuum or hear a hissing sucking sound, this is probably your problem.The 1/4" nipple on which the pressure switch sits may be plugged, although you would usually see abnormal high pressures as well if this were the case.
Hope this helps you out.

MMWS