In a recent test, water from the extension pipe on the side of the boiler dripped to the floor. This pipe was connected to a leaking pressure reducer or safety valve. This rather common problem is actually a reliably good thing and will protect you and your family from any failure of the boiler. Before installing these devices, it is not uncommon to hear boiler explosions that have disturbed home passengers.
But why are you leaking right now? It is important to understand the operation of the heating system to answer the question. The heating system is distributed in warm water with warm water. As the water is heated and cooled by the boiler, water runs out and pressure increases. In order to limit the heating system pressure, the DHW heating system contains various safety devices to keep your home safe.
The first and most important tool of the boiler is the Pressure Reduction or Safety Valve. The operating pressure of the domestic boiler system is 12 psi. If for any reason the boiler pressure is increased at safe operating pressure (the default pressure control valve), the valve opens. This overpressure condition is probably caused by a defective expansion vessel. If the boiler system does not allow sufficient water expansion in the system, the system pressure goes beyond the set value of the pressure relief valve. The leakage of the pressure relief valve due to this condition is generally cyclical as the boiler temperature is warmed up and cooled. There are two possible reasons for this.
Typical reason is that the boiler water system's cold pressure is higher than the standard expansion vessel standard, typically 12psi setpoint. However, if the feed valve in the boiler system is higher than this set value, the expander tank hose compresses before the boiler starts. After the boiler is switched on and the water is warmed up, the remaining thermal expansion can not be accommodated by the compressed bladder. You may need the internal pressure of the expansion vessel and / or the lowering of the pressure relief valve.
The second possible reason is the actual leakage or failure of the expansion vessel. In this scenario, the expansion tank no longer provides thermal expansion of the system because the entire tank is filled with water.
Other Causes of Leakage The pressure relief valve can be a consequence of age and valve damage. In this case it is recommended to replace the valve. Work should always be done by a qualified plumber.