The ZPS 1-M is Zehnder Pumpen's electronic level controller for single-pump wastewater and sewage lifting stations — a DIN-rail or wall-mounted control unit that automates pump operation based on real-time tank level. It supports three sensing methods: internal pneumatic pressure measurement, external float switches, and 4–20 mA analog transmitters, making it adaptable to new installations and existing tank retrofits.

How does pneumatic level sensing work in the ZPS 1-M?

A 6 mm or 8 mm hose (dip tube) extends from the controller into the tank. As the water level rises, air trapped in the tube compresses proportionally — the internal pressure sensor (0–10 kPa / 0–1 m water column) converts this to a fill level. This method has no moving parts in the wastewater, eliminating fouling issues common with float-based sensors. Float switches and a 4–20 mA input serve as backup or alternative level references.

How are alarms and faults managed?

The ZPS 1-M provides a potential-free changeover contact (rated 1 A at 230 VAC) for external alarm signaling — horns, strobes, or building management systems. An optional battery-backed alarm unit (Art.-Nr. 13001) triggers even during mains power failure. The controller logs the last 32–64 faults in non-volatile memory with time-stamped entries, and the LCD displays plain-text fault descriptions rather than cryptic error codes.

What can be programmed on the ZPS 1-M?

Accessible in STOP mode, the parameter menu covers pump start and stop levels, high-water alarm threshold, start delay (0–180 s), pump overrun time (0–180 s), and inter-pump delay for dual-pump variants. A 24-hour periodic test start prevents pump seizure during long idle periods. The phase monitor — detecting missing phases and incorrect rotation — can be disabled for single-phase pump applications. Service mode locks all parameters against unauthorized changes.