I have a combi boiler potterton promax. The Pressure was constant all summer but as the weather gets colder the pressure is dropping slightly. I would say it's about 0.1.-0.2 bar over a 6-7 week period. Is this drop to be expected as I'm assuming the temperature of the water in the system will drop when winter hits lowering the pressure slightly when no heating is being used? Or should I expect no loss of pressure? Also am I likely to find a leak this small?? No sign of wet ceilings or anything. Cheers.
So your realistically looking at the pressure fully dropping over the course of 6-12 months. This leak will be minuscule if there’s even a leak. No harm checking all visible pipework, valves and radiators though.