Pahlén variable-speed pump shows E08 and will not accept speed changes

Safety first: Turn off power to both the Pahlén pump and any connected automation systems before working on control wiring.

• Check control mode: On the Pahlén drive interface, verify that the control mode (local keypad vs. external control) is set correctly for your installation.
• Inspect low-voltage wiring: Open the low-voltage terminal compartment and confirm that 0–10 V, RS-485, or relay inputs are wired according to the Pahlén wiring diagram. Look for loose strands or shorts between terminals.
• Test without external control: Temporarily disconnect external control wires and set the pump to local/manual mode. If E08 disappears and the pump runs normally, the issue is with the external controller or wiring.
• Verify signal levels: If you have a multimeter and training, measure the 0–10 V signal or check continuity on digital inputs to ensure they are within expected ranges.

Persistent E08 with correct wiring may indicate a defective control input circuit on the drive, requiring professional service.