How Pressure Gauges Work?   Most gauges are constructed with
bourdon tubes to measure vacuum and pressure. The bourdon tube
flexes when pressure is applied, since it naturally wants to
straighten out but cannot because it is linked to a geared
movement.  The linear movement is changed as it tries to flex,
to a rotational one by means of small gears.  The gears in-turn
cause the pointer to indicate the measured pressure, in which
gauges like this are designed for clean, non-clogging liquids
and gases. Q&A Related to "How Pressure Gauges Work" To install
a oil pressure gauge you will have to purchase the one at the
auto parts store that you go to. The port to install the
mechanical part is about six inches behind the oil Pressure
Gauge is usually resistive or capacitive type. Whenever pressure
is applied, it's resistance or capacitance changes and internal
circuit calculates value. 1. Switch off the power supply to the
water pump. Open a faucet to drain the tank. 2. Use the wrench
to unscrew the brass fitting o