Stop the application within 100ms.

The boiler controller should not stop until it receives confirmation that the boiler stopped.

Reset the boiler.

Activate the Run Interlock on the boiler.

Start the primary fan for the pre-purge cycle. This fan runs for a fixed period of time.

Start the flow of gas and ignite the pilot.

The flame sensor on the boiler measures the level of the pilot flame. When the flame level reaches its threshold, the controller increases the fuel control valve to 10% and turns on the forced draft fan. The flow of gas to the pilot stops and the pilot turns off.

At this point, the boiler is running.

Turn off the boiler and initiate a purge cycle.

The fuel valve closes and the flame level is reduced to zero.

The primary fan turns on to start the purge cycle, which lasts for a fixed period of time.

At the end of this cycle, the system is back in its initial state.

Change the amount of fuel flowing into the boiler.

Until the boiler is running, this value remains at 0. Once the boiler is running, the value may range from 10-75%.

Indicates the current state of the system.

The primary fan runs during purge cycles to clear any combustible gasses that have accumulated in the system.

The pilot gas valve controls the flow of fuel to the pilot flame.

The pilot flame ignites the fuel provided to the boiler through the fuel control valve.

The forced draft fan ensures that sufficient airflow is provided to the combustion chamber while the boiler is running.