Burnham V8 Series manual Boiler Sequence of Operation

Figure 23A: Wiring Diagram, Water with Front Tankless Heater for Beckett Burners

BOILER SEQUENCE OF OPERATION

A call for heat by the thermostat energizes the L8124C control which in turn energizes the primary control to turn on the burner. The burner will operate in the following sequence: Prepurge for the first 10 seconds; fire until the thermo- stat is satisfied or the limit setting on the high limit is reached; post-purge for the last 10 seconds. The circulator will also operate when the thermostat calls for heat if the boiler water temperature is up to the setting of the low limit in the L8124C control. If boiler water temperature is below the low limit setting the burner will operate but the circulator will not, giving preference to the domestic hot water demand.

If the thermostat is not satisfied when the high limit is reached the burner will stop but the circulator will continue to operate until the thermostat is satisfied. Any time the boiler water temperature drops below the setting of the low limit the burner will be energized in order to maintain domestic water temperature.

On burner start, if the cad cell does not see flame within approximately 15 seconds, primary control will shut burner down and enter into a recycle mode, after 60 seconds burner will restart and repeat trial for ignition. If after three

(3)trials for ignition, flame is not detected, control will enter into restricted mode and must be reset manually before burner can be restarted.

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