Superior Performance by Design
Hydrolevel low water cut-offs are electrically operated. A probe is installed in the boiler shell or external manifold, and is connected to the control unit. Water is used as a conductor to complete the circuit between the probe and the boiler shell. When water is in contact with the probe, the circuit is completed; when the water level drops below the probe, the circuit opens. Hydrolevel controls provide contacts to de-energize the burner circuit in a low water condition.

Model	Voltage	Manual Reset	Test Button
500	24V
550	120V
700	24V
750	120V

Note: by adding "SV" to the end of the above model numbers (example: 550SV), the control will be equipped with the shorter model EL 1214-SV probe suitable for mounting in standard reducing tees.

Manual Reset
Shuts down the burner in a low water condition. Requires manual reset if the water remains below the probe for 30 seconds. Power interruptions will not impact the manual reset feature. When power is restored, the control will return to the same state it was in prior to the interruption fully meeting ASME CSD-1 requirements.

Test Button
Tests control operation without lowering the water level. Depressing the test button de-energizes the burner circuit and lights the low water indicating lamp.