Which component discharges when the boiler pressure reaches its limit?

Which component discharges when the boiler pressure reaches its limit?

• A. Expansion tank
• B. Temperature gauge
• C. Pressure relief valve
• D. Circulator

Answer: (C)

Boilers have a safety device that vents excess pressure to prevent a dangerous overpressure condition. When the boiler water heats and pressure climbs to a preset limit, the pressure relief valve opens and releases water or steam through a discharge path. This action lowers the pressure back to a safe level and helps protect the boiler from damage or failure. The expansion tank, on the other hand, absorbs the extra volume that water expands into as it heats, helping to manage pressure changes rather than discharging at the limit. The temperature gauge simply indicates temperature, not a venting action. The circulator (pump) moves water through the system and does not function as a safety discharge.

Boilers have a safety device that vents excess pressure to prevent a dangerous overpressure condition. When the boiler water heats and pressure climbs to a preset limit, the pressure relief valve opens and releases water or steam through a discharge path. This action lowers the pressure back to a safe level and helps protect the boiler from damage or failure.

The expansion tank, on the other hand, absorbs the extra volume that water expands into as it heats, helping to manage pressure changes rather than discharging at the limit. The temperature gauge simply indicates temperature, not a venting action. The circulator (pump) moves water through the system and does not function as a safety discharge.