Hoffman Controls 814 10EH Control Els PW 17895 Power Outage Protection: Features a Power Outage Protection: Features a replaceable CR2 lithium battery to maintain time and non volatile memory for programmed schedules Replacement is recommended when the differential pressure reaches 10 psi or during annual maintenance intervals to prevent energy loss and oil carryover It converts these inputs into a proportional output voltage to adjust fiber optic pulse widths or phase angle firing for the motor the 24V signal must be provided by the system's existing class 2 transformer or a dedicated external power source to trigger the control logic