According to the International Mechanical Code, all boilers shall be equipped with a safety relief valve. These safety relief valves permit the emergency discharge of water under pressure from thermodynamic expansion. Whether during testing or disrepair, it is possible to find a faulty safety relief valve that will need immediate attention because of its crucial role in preventing damage or explosion of the boiler. Fortunately, the options for repairing or replacing are limited and facilitate a quick turnaround from down time due to failure.
Shut the automatic fill valve.
Check the pressure on the boiler to confirm that it is not pressurised above the minimum operating pressure of the relief valve. The minimum operating pressure or relieving pressure of the relief valve is clearly stated on the information tag attached to the relief valve.
If the boiler is over pressurised, the boiler pressure must be lowered to less than the minimum operating pressure of the relief. This can be accomplished by continuing to drain water from the boiler until the gauge reads the appropriate pressure.
Lift and release the test lever to reseat the valve.
If Step 4 does not work, tap with moderate force on the side of the relief to free up possible debris or corrosion from the valve seat and repeat Step 2.
If these steps do not work to reseat the valve and the boiler is under the minimum operating pressure of the relief valve, the relief valve will need to be replaced.
It is possible for an automatic fill that is set to the wrong pressure or is failing to cause a relief valve to "dump" or relieve pressure. Any failure of the relief valve should signal the boiler operator to replace the relief valve at the earliest possible convenience, as these are critical safety devices.
It is critical address all relief valve failures immediately to avoid possible damage or explosions.