This is an instruction manual that introduces the features and usage methods of Hanna Instruments' HI 7871- HI 7873 HI 7874 Level Controllers
This document is the instruction manual for the Hanna Instruments HI 7871, HI 7873, and HI 7874 Level Controllers. These instruments are designed as 2-wire transmitters specifically for controlling liquid levels in biological and industrial water treatment applications over long distances.
The manual covers system components including the level controller unit (HI 7871 or HI 7873) and the HI 7874 level transmitter with bar holder. It details installation procedures, electrical connections using the HI 7164 undecal connector, operational logic for high/low levels and overflow alarms, and troubleshooting steps for circuit faults.
| Transmitter max distance | 100 m (330 feet) |
|---|---|
| Power Supply | 110/115 Vac or 220/240 Vac; 50/60 Hz |
| Environment Temperature | 0 to 50°C (32 to 122°F) |
| Weight | 250 g (8.8 oz.) |
| Output Contact | 1 relay or 2 relays |
The HI 7871, HI 7873 and HI 7874 are warranted for two years against defects in workmanship and materials.
The HI 7873 needs 4 measuring bars (reference, low, high, and over), whereas the HI 7871 requires only 3.