Boiler shows E14, domestic hot water flow is detected but burner does not modulate correctly

Safety: Turn off power and close the cold water supply to the boiler or indirect system before disassembling any water components.

• Step 1 – Clean inlet screen: On combi Triangle Tube boilers, locate the cold water inlet and remove the filter screen. Rinse out debris and reinstall.
• Step 2 – Inspect DHW flow sensor: Find the DHW flow sensor or flow switch on the cold inlet or DHW circuit. Remove it carefully and check for scale or debris preventing movement. Clean gently with vinegar if scaled.
• Step 3 – Check wiring: Verify the sensor’s wiring harness is intact and firmly connected to the control board.
• Step 4 – Restore water and power: Open the cold water valve, check for leaks, then restore power and run a hot water tap to test operation.
• Professional service: If E14 persists, the flow sensor or control board may need replacement by a technician.