Stage 1 - installation

The Valve Cap is screwed onto the valve stem. The installation process requires to screw the cap down firmly in order to set it correctly.

 

The center spring has pushed open the valve and the tire pressure flows into the Valve Cap and into the reference chamber.

STAGE 2 - MONITORING

The Valve Cap is firmly screwed down on the valve stem.

The top of the valve stem and the seal in the Valve Cap has made an airtight connection.

The mouth of the pressure/reference chamber is permanently sealed with the tire pressure trapped inside the chamber.  The one way nut below the chamber seal will keep the chamber seal in place and airtight.

The Valve Cap is now in its regular state where it monitors the tire pressure all the time without using any energy from the batteries.

stage 3 - Warning

The tire pressure has dropped below the trigger point.

Due to the higher pressure in the reference chamber, the sensor has popped up and hit the battery contact washer.

The LED will continue to flash until the pressure in the tire has been corrected to original pressure.

Note:  The Valve Cap will never warn for over pressure, since that is a normal occurrence when the tires get warm.  Sometimes the owner elects to increase the regular tire pressure during special occasions; (pulling a trailer or having a extra heavy load) this will not change the original trigger setting.  The reference chamber is already closed the settings will not be affected by this temporary situation.  The warning level will always be what it is set at the first time.