A small change in indicated pressure as a heating system warms and cools is normal. Repeated loss of pressure, however, can indicate that water is escaping or that an expansion-related component is not operating correctly.
Leaks on the heating system
Water can escape from radiator valves, pipe joints, components or concealed pipework. Some leaks are obvious; others are small enough to evaporate or remain hidden.
Expansion vessel problems
A sealed heating system needs to accommodate the expansion of water as it heats. If the expansion vessel is incorrectly charged, undersized or defective, system pressure can rise excessively during heating and contribute to discharge through a safety valve.
Pressure relief discharge
If a pressure relief valve has operated, water may discharge externally. A competent engineer can investigate why it operated and whether the valve and expansion arrangement require attention.
Boiler or system leak?
The pressure gauge represents the sealed heating circuit, so the cause may be within the boiler or elsewhere in the heating system. Diagnosis is needed before assuming which component is responsible.
Heating repairs in Hull
If your boiler is repeatedly losing pressure, Envirowarm provides boiler and heating fault finding in Hull and East Yorkshire. Contact us with the boiler make/model and what the pressure does when the system is cold and hot.
Boiler losing pressure? Request boiler fault finding in Hull →