If there is a water pressure loss is in a boiler it is a very good indication that there is an issue with the boiler or the system. The pressure should be visually checked straight away. The gauge will be on the boiler front. Losing the water pressure can be as a result of a water leak or maybe an expansion vessel failure causing damage to the pressure relief valve. London Plumbers are fully qualified to diagnose and rectify. There is a fundamental need for constant water pressure in a heating system to allow the boiler to operate correctly. The pressure in most combination boilers is kept rock steady by the flow of cold water from the mains supply through a mechanism known as the ‘filling loop’. A trained Plumber can re-pressure a system. You may be able to manually regulate the amount of water circulating your radiator by using the filling loop. This means you can re-pressurise your boiler. Read your boiler’s instructions to see if can be re-pressurised manually. If not, follow this brief guide to begin the re-pressurising process. Firstly, identify the filling loop and the pressure gauge. Next practice switching the boiler controls to off before attempting to top up the pressure. The filling loop should have a silver flexible tube with two handles; in the off position the handles will be across the flow of the pipe. You will need to slowly turn them so they are in line with the pipe. You should now hear the water moving through into the boiler. Carefully check the pressure gauge as it climbs into the green area or the 1.5 bar marker. Now turn the handles back to the original position. A normal mistake to make is to over pressurise the system, this will happen when you cannot watch see gauge as you increase its pressure. Therefore if you can’t monitor the gauge yourself, get someone else to come and help you.