The burner on a gas hydronic heating system is primarily controlled by what?

In a gas hydronic heating system, the burner is primarily controlled by high-limit control, which is designed to ensure safe and efficient operation of the system. High-limit control functions by monitoring the temperature of the water in the system. If the temperature exceeds a predetermined set point, this control will shut off the burner to prevent overheating and potential damage to the system or risks like water vaporization.

While a thermostat control is also important, as it helps maintain a desired ambient temperature by signaling the burner to turn on or off based on the room temperature, the primary function of regulating the burner to prevent over-temperature situations falls under high-limit control.

Pressure control and flow control are relevant in the context of maintaining system pressure and ensuring adequate water circulation, but they do not directly manage the burner operation in the same way that high-limit control does by responding to temperature extremes.