Error F6

Safety precautions:

- Before doing anything, read the boiler manual for relevant warnings. If you have any doubt, call a Gas Safe engineer.

- Isolate electrical power to the boiler at the fused spur before you open the boiler cover or touch wiring. Do not work on the boiler when wet or in poor weather.

- Do not attempt gas-side work, or swap PCB components, unless you are a qualified engineer.

Initial checks homeowners can do (safe, non-invasive):

1) Note the exact fault code and any other behaviour (no CH, no HW). Try a simple reset: press the boiler RESTART button or switch the boiler off at the fused spur for 1 minute and switch back on. If F6 clears and does not return, monitor for recurrence.

2) Locate the outside sensor (usually a small probe or box mounted externally on an outside wall or in a weather sensor junction box). Visually inspect for obvious damage, water ingress, crushed cable, or disconnection. Ensure the sensor is not covered by debris or paint.

3) Follow the sensor cable from the outside back towards the boiler and look for visible damage or loose connectors. If the cable has been chewed or cut, stop and call an engineer.

Specific diagnostic and fix steps (requires basic tools and some electrical confidence):

4) If comfortable with a multimeter and able to isolate power, you can check continuity of the sensor cable. Turn off power at the fused spur and confirm the boiler is isolated. Remove any external sensor cover to access wires and at the boiler termination point access the sensor terminals (refer to manual for terminal location). Check continuity between the sensor end and the boiler terminals. Loss of continuity indicates a broken cable or connector.

5) Check the sensor resistance. Many outside sensors are NTC thermistors whose resistance changes with temperature (resistance falls as temperature rises). With power off, measure resistance across the sensor wires. Warm the sensor gently (cup in hand or briefly warm with your breath) and see if resistance changes. If the reading is open circuit (infinite) or reads a fixed value that does not change with temperature, the sensor is faulty. NOTE: exact resistance values vary by model — consult the boiler manual or manufacturer spec for exact numbers.

6) With power isolated, check that the sensor wiring is correctly secured at the boiler terminal block and that connectors are not corroded. Re-seat any removable plugs or terminal screws and ensure good contact.

7) If you find a damaged cable or connector and you are competent with low-voltage wiring, you can replace/repair the cable or connector. Use a proper sensor replacement specified by Ideal for your model. After any wiring work, restore power and test. If unsure, stop and call an engineer.

When to call a professional:

- If F6 persists after reset and simple visual checks, call a Gas Safe registered engineer or Ideal service team.

- If you are not confident using a multimeter, opening the boiler casing, or handling wiring, call a professional.

- If the engineer determines the sensor is faulty they will replace it, and if the wiring or PCB is at fault they will carry out the necessary repairs.

Other important notes:

- Replacing a failed outside sensor is a common repair and normally straightforward for an engineer; however if the problem is intermittent it could be caused by wiring damage, moisture ingress, or a PCB issue which will need professional fault-finding.

- Avoid repeatedly resetting the boiler if the fault returns; document when it happens and any conditions (heavy rain, cold snap) to help the engineer diagnose.

- Do not attempt gas or combustion component repairs yourself. Calling a Gas Safe registered engineer is the correct course if the fault cannot be cleared by basic checks.