Pressure Switch Wiring and Details

This article is to explain how the different pressure switches work and the differences between the ones used with our system. The Reverse Action Pressure Switch or RAPS and the A9 pressure switch.

What is a pressure switch?

     A pressure switch is a device used to automatically shut off a pump when pressure has built up in the pipes leading from the well. This can be due to a valve or faucet, a pressure tank or even a manual float valve assembly.

     A pressure switch is attached into the piping and uses a rigid diaphragm to sense pressure. once the set pressure has been reached, usually 30 PSI-50 PSI, the diaphragm flexes inward and physically pushes a circuit closed causing a reaction.

     The two springs inside the switch allow for the pressure ratings to be adjusted. The small spring changes the pressurization needed to activate the switch, from 50 up to 70 PSI.

    The larger spring adjusts both the on and off ratings, staying about 20PSI from each other. From 30/50 PSI to 40/60 PSI or 50/70 PSI.

     The black hexagon is the diaphragm covering a steel disk. The steel disk has two prongs that when forced up, activates the terminals. The switch is wired into the control box using two wires that are connected on the same side of the pressure switch, we never want to connect one wire to each side.

    The pressure switch that we use is called a Reverse Action Pressure Switch or RAPS, this means that the action that starts when the terminals connect is to turn the pump off. When the switch turns on, the pump turns off.

     One issue we sometimes see with clients is that they will see the lever on the side and misunderstand what it means. There are two settings to the lever: AUTO and ON. The AUTO setting allows the switch to open and close as the pressure fluctuates, the way we want the switch to work. The ON setting causes activation of the switch, turning off the pump and toggling Tank Full. Some clients believe ON is the setting that causes the switch to work but it actually just shuts off the pump.

     The RAPS should never get wet, be set sideway, upside down or be set in the well as it will cause it not to work properly.

Here's a video that can help provide a visual reference!

NOT AS COMMON

This pressure switch is designed to be used in pitless adaptor or trenched  systems. See An Explanation on Winterizing

These switches are able to be put down the well and come in preset pressure ranges. These ranges cannot be adjusted.

   

     When wiring for an RPS system, two wires with be attached to the top two prongs and come prewired for the customers from the warehouse. They come with 10 feet of sensor wire that can be spliced to a longer section of 18-22 AWG wire and connected to COM2 and TH on the control box.

     The switch can we rewired in the same way as the pro float switch, to either be normally open or normally closed, switching the action on activation. Normally Open or NO and COM allows the switch to stop the pump when activating while Normally Closed or NC and COM allows the pump only to run when the switch is activated so this may sometimes cause an issue of always having Tank Full toggled on.

Here is a link  to the Transducer operating Instructions

Solar Pump Pressure Shutoff with Reverse Action Pressure Switch