BoilerFaultCodesRemeha 6 1. Fault Code
Also written as 61 — same fault.
The Remeha 6 1. fault code means: your boiler has detected that a safety sensor meant to monitor air flow is stuck or blocked, preventing the system from starting up safely.. It appears on 3 Remeha models in our database.
Technical description: Air transport: Air differential switch does not open: Air differential switch defective; Extreme draft through flue gas discharge duct; Short-circuit in wiring.
What causes the Remeha 6 1. fault?
This fault occurs when the boiler's internal safety sensor incorrectly detects that air is moving through the system before the fan has even started. The most common reasons are a sensor that has physically jammed in the 'on' position or debris and moisture blocking the small silicone tubes that monitor air pressure. It can also be caused by heavy winds blowing directly into the external flue pipe, forcing the sensor to trigger prematurely.
This issue often occurs during periods of extreme wind or stormy weather, as gusts can create enough pressure in the flue to confuse the air pressure sensor.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Remeha models that show the 6 1. fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Remeha 6 1. fault code information on this page is sourced and cross-checked against the official Remeha service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026