Morning all, I have a frustrating problem. Maybe somebody can help? I am using a purefreedom 50l trolley, I have had it for around three months and in the main very happy with it. The problem is that the system very easily gets air locks in the pipes, you can see them through the clear tubes. I have tried all the usuall (running on full power, purged with shut off valve, tightened all pipe clips and screws). Some days it takes around 25l of water before it settles. Anybody else had issues with this? Any ideas? Much appreciated, have a good day.