The MAXI AP400 G‑L1 is a Mikrofill MAXI AP pressurisation unit, designed for maintaining pressure in large sealed heating and cooling systems. It is floor‑mounted, has a usable water tank capacity of 18 litres, supports sealed systems up to 300,000 litres. AI MODE ,ENERGY EFFICIENT,H13 TRUE ION FUNCTION INDICATOR,FILTER RESET INDICATOR,35 W