Can someone please answer me this regarding a combi boiler: when the gauge reads 0 pressure (0 bar) on the dial, does this mean the boiler is empty or the system is empty up to boiler height/level? To be clearer what I mean is, if I want to drain water from my system to replace a faulty air bottle inside the boiler casing, how can I be sure water will not escape pour out when I remove the old 1!! The boiler is in our ground floor kitchen.
Thank you for helping.
Thank you for helping.