Most of the times, central heating boilers lose pressure because of leaks developing in its various components. These can be pressure relief valves, auto air vents, expansion vessels, and pressure gauges. You need to find the exact reason for the loss of pressure and carry out the necessary repairs or modifications so that the boiler can start working as before.
Central Heating Systems
Central heating systems will also have radiators that are required to dissipate the heat, and defects in these radiators can also at times lead to a loss of pressure in boilers. In fact, defects in radiators are one of the most common causes of pressure loss. Heated towel rails also use water from the boiler, and can be the reason for this problem. Eekaleakdetection.co.uk suggest that you need to visually check all radiators, their valves, and any installed towel rails. It there is a leak, there will be signs of water escaping and this will lead you to the culprit responsible for pressure loss. Weeping radiator valves are enough to cause this defect in the working of a central heating system. Connections in the various radiators can work loose, and lead to a drop in pressure in the central heating boiler. Air build-up in radiators can also lead to problems in boilers, and this can be a simple thing to repair, by releasing bleed keys and allowing the air to hiss out. Once the air is gone, water will start to flow out, and you will know that all the air has been removed.
Pressure Release Valves
Pressure relief valves are required to operate when there is an abnormal build-up of pressure in the boiler, and if this valve fails it can lead to a drop in pressure, as the defect in the PRV will prevent the pressure from building up, and steam being released before the required pressure is attained. The refilling of boilers often leads to building up of air in the heating system, and auto air vents are installed to allow this air to escape. When these auto air vents are defective this can also lead to pressure loss in the boiler. Another component of a central heating system that can be responsible for pressure loss in boilers is the expansion vessel. This vessel is a small tank that prevents excessive pressure buildup in boilers. These vessels have diaphragms that can degrade, valves that leak, and other conditions that lead to its effect on the pressure in a boiler. Repressuring the expansion vessel can solve this problem.
Checking for leaks
A central heating system has a lot of pipework and some of the joints in this pipe are soldered and will turn weak after being in use for some time, or if the installation has not been done properly. Check for leaks here and redo all the defective joints. Boilers have pressure gauges and a defective pressure gauge can lead to an incorrect reading of pressures, and wrongly indicate low pressures.
The speed at which a boiler loses pressure can indicate the extent of the problem, and if this happens quickly, you have a major problem that requires immediate attention.