You may have air pockets trap in the cooling system.
Only when there is a failure in the cooling system.Only when there is a failure in the cooling system.
yes
It is to pressurize the fuel system and allows the vehicles fuel system to keep adequate pressure after the vehicle has been started.
Cycle the ignition on and off several times holding it in the on position for a few seconds each time. Doing this 4-5 times will allow the fuel pump to pressurize the fuel system.
To avoid over heatig
If you over-pressurize the system you could cause one of the hoses to burst or the system to leak at a mechanical coupling and cause the compressor to fail prematurely.
you can pressurize the system to find a leak
Possibly over heating and worst case scenario a blown engine.
Air in the system. Bleed the cooling system and remove any trapped air pockets.
pressurize the system
Hydra-boost
If you are talking about a normal house, all you need to do to 'pressurize the system' is turn on the main valve, then open up each tap/faucet in turn until water is flowing freely.