PB-1525 Wood Pellet Burner System: Installation and Operation Manual
Rev 1.0, OCTOBER 2011
Page 32 of 67
Shutting Down 1793
185 279°F _
Starts: 502
Disa
Figure 3.6: PB-1525 Burner Controller in the Shutting Down State
As depicted above, the System State is “Shutting Down”. The unit is now
monitoring the flame sensor to ensure all fuel in the burn chamber is
extinguished. The length of time of this state varies with the amount of fuel
left in the burn chamber at the end of the firing state as well as the
physical makeup of the pellet bed. Disabling the unit in this state will
cause the system to continue the full shut down sequence including the
purge, then the system will ignore the thermostat (See the section on
System Disabled).
Purging
The Purging state indicates the system has detected the absence of
flame in the burn chamber and is completing the shut down mode. In the
Purging state, the unit is running the combustion blower at high speed and
monitoring the flame sensor value; the system will no longer feed pellets
into the burn chamber. The Purging State runs for a set time duration.
Upon completion of Purging the system will either enter the Idle State if the
thermostat is not calling for heat or the Feed Start State if the thermostat is
closed. Figure 3.7 below illustrates the controller in the Purging state.
