GLOW WORM ULTIMATE BOILER PRESSURE GAUGE QUESTION

[haydan]

hi
sorry am not very handy when it comes to boilers.
i have a glow worm ultimate boiler.
there is a red and a black pressure gauge.the red one is on 1 bar but the black one is on zero.
does anyone know what the red arrow and the black arrow is for and should i fill the system with water . ( i think i know what tap (or 2 ) to open up

many thanks

 

[Boilerman2]

The RED needle is showing what the Cold Fill Pressure SHOULD be
the Black needle is showing what the pressure actually is,
open up the 2 filling loop valves until the black needle is a 1 Bar (the same as the RED Indicator needle) - note once the system has heated the black needle will have risen to a higher pressure (Above the RED needle)
THIS IS EXPANSION OF HEATED WATER AND IS NORMAL)