Display shows E7, furnace may run at reduced output or shut down

Safety first: Isolate electrical power before touching the pump or internal hydraulics. Surfaces may be hot.

• Check system pressure: Verify that the system pressure on the gauge is within the recommended range (typically 1.0–1.5 bar when cold). Top up via the filling loop if low, following the user manual.
• Bleed radiators: Use a radiator key to bleed air from the highest radiators until water flows steadily. Recheck and adjust system pressure afterward.
• Inspect pump operation: With power restored and a heat demand present, place a hand on the circulation pump body. You should feel vibration and slight warmth. If the pump is silent and cold, check its electrical connector and fuse.
• Clean system filter: If a magnetic or mesh filter is installed on the return line, isolate it and clean out sludge and debris.
• Technician tasks: If E7 persists, a technician should check pump performance, open/close any motorised valves, and flush the system if heavily sludged.