Wilo Yonos PICO Pumps
17 fault codes documented
Bars bottom to top blink - Pump venting function active
The LED display shows bars running from bottom to top. This indicates that the pump venting function is active.
Building does not get warm - Heating output too low
The building is not getting warm, suggesting the thermal output of the heating surfaces is too low for the pump's current setting.
E04 - Undervoltage detected
The LED display shows E04, indicating that the power supply voltage to the pump is too low. The pump may switch off.
E05 - Overvoltage detected
The LED display shows E05, indicating that the power supply voltage to the pump is too high. The pump may switch off.
E07 - Generator operation (no mains voltage)
The LED display shows E07, indicating that water is flowing through the pump but it has no mains voltage. This is sometimes referred to as generator operation.
E10 - Rotor blocked
The LED display shows E10, indicating that the pump's rotor is blocked. The pump may switch off and attempt to restart.
E11 - Dry run detected
The LED display shows E11, indicating a dry run situation, meaning there is air in the pump. The pump may switch off or run with limited output.
E21 - Overload
The LED display shows E21, indicating an overload condition. This could be due to a sluggish motor or the pump operating outside its specifications, possibly with high module temperature. The pump speed will be lower than normal.
E23 - Short-circuit
The LED display shows E23, indicating a short-circuit or that the motor current is too high. The pump will likely switch off.
E25 - Winding defective
The LED display shows E25, indicating a defect in the motor winding. The pump will likely switch off.
E30 - Module overheating
The LED display shows E30, indicating that the interior of the control module has become too warm. The pump may switch off.
E36 - Module defective
The LED display shows E36, indicating that the electronics within the control module are defective. The pump will likely switch off.
Green LED flash - Restart or Venting function activated
The function LED briefly flashes green when the manual restart or the pump venting function is activated.
Outer segments clockwise blink - Restarting or Venting active
The LED display shows the outer segments in a clockwise fashion. This indicates that a restart or the pump venting function is active.
Pump making noises - Potential cavitation
The pump is making unusual noises, which could indicate cavitation. This happens when there isn't enough pressure in the suction line.
Pump not running when power is on
The pump is not operating even though the power supply is switched on. This could be due to a fuse issue or a power interruption.
Red LED solid - Fault signal active
The fault signal LED lights up solid red, indicating an active fault condition. The pump may switch off and attempt to restart depending on the error code.