When utilizing Terminal 1 and 2

the SLD series is specifically designed for suction line applications

typically in the thermostat wiring or a failing contactor coil

Professional installation is required to ensure proper insertion depth and electrical connection within the low-voltage control string

technicians should verify compatibility with the specific model and serial number

Hydrolevel 24SV Low Water Cut-Off 30067439-890 When utilizing Terminal 1 andThe Hydrolevel 24SV Low Water Cut Off is a heavy duty electronic safety control designed for 24Vac hot water boiler applications. Engineered with a compact NEMA 1 enclosure, this unit is built for tight residential and light commercial boiler rooms where space is at a premium. The Hydrolevel 45 245 utilizes a specialized EL1214 SV sensing probe, which features a shorter length (2 1 16" insertion) specifically designed to fit into standard 3 4" NPT