How to Fix / Troubleshooting

Safety: Isolate electrical power. Be prepared for water drips when opening pump vents.

Locate the circulation pump on the flow or return line near the boiler.
Remove the pump front screw/vent plug (if present) and insert a screwdriver into the rotor slot. Gently turn to free a stuck rotor.
Bleed air from the pump housing until water flows steadily, then refit the plug.
Check that the pump isolation valves are open.
Restore power and feel the pump body; it should vibrate slightly and warm up during operation.
If the pump remains cold and silent, check the electrical connector and fuse. If power is present but the pump does not run, it is likely defective.

Persistent E10 after freeing and bleeding the pump indicates the need for pump replacement or control board diagnosis.

E10 displayed; controller indicates circulation pump fault or no flow

Possible Causes