Why is my Low Pressure Cut-Out switch nuisance tripping?

Nuisance tripping of a Low-Pressure Cut-Out pressure switch can occur for the following reasons.

#1 -The Cut in pressure is set too close to the pressure tanks pre-charge. There should be a minimum of 2-5 PSI difference.

EXAMPLE: If switch cut-in is 30 PSI tank pre-charge should be 25-28 PSI maximum.

TIP: Setting at higher 5 PSI difference will reduce the risk of nuisance tripping.

Other factors to consider:

  • Pressure Switches are not individually tested for pressure settings, a switch with a 30-50 setting could possibly be set 28-48.
  • Pressure Switches will sometimes stick slightly – The same switch could possibly come on 1 or 2 PSI different one cycle to the next.
  • Change in ambient temperature can affect the pre-charge pressure in the tank. It is common that nuisance tripping will occur when the seasons change affecting the ambient temperature at the tank location. For example if a system is set up in the winter with a 2 PSI difference between the pump cut-in and the tanks pre-charge pressure, you may see nuisance tripping when heading into the spring / summer season. As the ambient temperature increases around the tank, the air inside the tank warms and expands increasing the internal tank pre-charge pressure eliminating the required minimum of 2 PSI pressure difference.    
#2 -Poor pump capacity, insufficient to retain the required system pressure during high demand periods.