Burnham V8 Series Instructions.pdf - Heating Help

Figure 21: Wiring Diagram, Steam, Optional McDonnell & Miller 67 Float LWCOBOILER SEQUENCE OF OPERATION WITH FLOAT LWCOWhen the thermostat calls for heat, it energizes the cad cell primary control, bringing on the burner. The burner willoperate in the following sequence: Prepurge for the first 10 seconds; fire until the thermostat is satisfied or the limitsetting on the high limit is reached; post-purge for the last 10 seconds. When the high limit control restores the circuiton a drop in pressure, the burner will start if the thermostat is still calling for heat. The low water cut-off will shut downthe burner if the water level in the boiler drops too low. The control resets and restarts the burner with a call for heat afew seconds after the water is returned to its normal level.On burner start, if the cad cell does not see flame within approximately 15 seconds, primary control will shut burnerdown 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 beforeburner can be restarted.When there is no demand for heat, the operating control will maintain the boiler water temperature at the selectedsetting for proper operation of the domestic water heater, if equipped with optional tankless heater.40