Finally , the barometer needs to be exclusively filled with pure rainwater , as tap water contains many minerals which may be detrimental to the barometer .
Wear and tear also places considerable strain on the vacuum system 's vulnerable pump , its 11 solenoid valves and its relays .
The barometer needs to be exclusively filled with pure rainwater , as tap water contains many minerals which may be detrimental to the barometer .
Wear and tear also places considerable strain on the vacuum system 's vulnerable pump , its 11 solenoid valves and its relays .