Well Pump Pressure Adjustment

Beltzington · Feb 5, 2012

Several weeks ago I raised the pressure by turning the #1 adjustment nut CW increased from 20/40 to 50/70. Turned the pump off relieved system pressure and set air-tank pressure to 43psi. Seemed to work fine until a couple weeks later I noticed the low pressure cut-on was chattering the relays.

After the pump cuts off with one hose-bib fully open water pressure bleeds of very smoothly the first 10psi it then almost immediately drops the last 10psi and then the relay bounces on and off several times until the pressure gets above 55psi.

I played with both the range and the pressure cut-off adjustments but it wasn't until I lowered the air-tank pressure to 35psi I finally got it to stop bouncing the pressure relays at low end pressure.

Anyone think this is abnormal behavior, is my switch bad or have I set the on-off switch at too high of range? TIA

Carl_NH · Feb 5, 2012

With the 50-70 pressure you are losing a fair amount of storage capacity indicated by the fast drawdown in the last 10 PSI then when the pump kicks on the pressure switch thinks its statisfied and cycles off. The low pressure cutoff is usually around 20 PSI for a 40-60 setup so I am not sure what is chattering? is it the high pressure side turning off because the initital surge of water from the pump?

Personally I would set it at 40-60 with the bladder tank pressure of 37-38PSI and then set the differential (smaller screw) for the cut in pressure. I also think the different switches likely have different springs - 20-40 vs 40-60 so you might want to get a higher setting switch.

I run two tanks in series with 28 GPM drawdown, with the air set at 38PSI, cut in is 40 PSI cutoff is 64 PSI with a 1.5 HP 13 GPM pump, so the pump runs for about 2 minutes to fill the tanks.

Carl