When I turned on my Potterton Puma boiler to heating the boiler pressure drops it looks when I drain the air from radiaters the water drains. How can I recharge water?
Look in intruction book. You will need to release a valve on the boiler then open another valve to let water in. You will see the pressure rise. Stop when it reaches the target pressure. It is normal for the pressure to drop when you release air from the radiators.