What burner control prevents excessive water temperature in a gas fired hydronic system?

What burner control prevents excessive water temperature in a gas fired hydronic system?

• A. High limit
• B. Low limit
• C. Thermostat
• D. Aquastat

Answer: (A)

In gas-fired hydronic systems, safety devices monitor boiler water temperature and shut the burner off if overheating is detected. The device that prevents excessive water temperature is the high limit. It acts as a safety cutoff in the burner circuit and opens to stop firing once the water reaches the preset maximum, allowing the system to cool and preventing damage or danger. The aquastat is the normal temperature control that maintains the boiler at its setpoint by turning the burner on or off during regular operation, but it isn’t primarily a protective limit against overheating. A thermostat controls space temperature and signals for heat, while a low limit protects if the water gets too cold, not too hot. So the high limit is the best choice for preventing excessive water temperature.

In gas-fired hydronic systems, safety devices monitor boiler water temperature and shut the burner off if overheating is detected. The device that prevents excessive water temperature is the high limit. It acts as a safety cutoff in the burner circuit and opens to stop firing once the water reaches the preset maximum, allowing the system to cool and preventing damage or danger. The aquastat is the normal temperature control that maintains the boiler at its setpoint by turning the burner on or off during regular operation, but it isn’t primarily a protective limit against overheating. A thermostat controls space temperature and signals for heat, while a low limit protects if the water gets too cold, not too hot. So the high limit is the best choice for preventing excessive water temperature.