Error 5 red flashes

Safety precautions:

1. If you smell gas, evacuate the property, do not operate electrical switches, and call the gas emergency number or your gas supplier immediately. Do not attempt any checks.

2. If you are not comfortable working around boilers, do not proceed — call a Gas Safe engineer.

3. Turn off the boiler at the electrical isolator if instructed by the engineer or if the boiler is unsafe. Do not attempt internal repairs or remove covers — internal components carry dangerous voltages and gas connections.

Initial checks a homeowner can do (no internal access):

1. Note the exact fault indication: count the red flashes and write down any other lights or messages shown. Take a photo of the control panel and any displayed codes.

2. Check mains power: confirm the boiler has power, check the wall isolator and household fuse or RCD hasn’t tripped.

3. Check system water pressure on the boiler gauge. Baxi boilers normally require roughly 1.0–1.5 bar for normal operation. If pressure is well below 1 bar, the boiler may lock out.

4. Inspect external flue and condensate pipe: make sure the terminal is not blocked and the condensate pipe is not frozen or split (clear snow/ice or debris if safe to do so).

Specific diagnostic and simple fix steps (only for non-intrusive tasks):

1. Try a controlled reset once: locate the boiler reset button or selector (often marked with a flame symbol or R). Press and hold the reset for about 5–10 seconds and release. Wait for the boiler to attempt restart and observe whether the 5-red-flash returns. Do not repeatedly press reset if the fault persists.

2. If pressure is low and you are confident doing so, repressurise the system using the filling loop: with the boiler powered off and following the boiler manual, open the filling loop valves until the gauge reads about 1–1.5 bar, then close the valves and secure the loop. After repressurising, perform a single reset as above. If you are unsure how to do this, call an engineer.

3. Check for recent events that could explain the error: recent power cuts, lightning strikes, or interrupted supply can corrupt parameters. If this was a one-off and the reset cleared the fault, monitor the boiler. If the same fault returns, do not keep resetting repeatedly.

4. If the boiler shows additional symptoms (no heating/hot water, repeated start attempts, unusual noises, or other error codes), document them — these will help the engineer diagnose the root cause.

When to call a professional and what to tell them:

1. Call a Gas Safe registered engineer if the 5-red-flash returns after one controlled reset, if the boiler will not operate, or if you are unsure about any step. This fault commonly requires specialist diagnostics and may need PCB/PSU replacement or repair of internal wiring/communication components.

2. When you contact the engineer, give the boiler model, serial number, describe the fault (5 red flashes / PSU or parameter error), list the checks you performed (power, pressure, reset, condensate/flue checks), and send photos of the display and boiler rating plate if possible.

3. If your boiler is under warranty or covered by a service plan, contact Baxi or your service provider first and follow their guidance.

Final notes and precautions:

1. Do not attempt to replace the PCB/PSU or access internal wiring yourself. These are specialist repairs for a Gas Safe registered engineer.

2. Avoid repeated resets; if a reset does not permanently clear the fault, further use may cause additional damage.

3. Keep a record of fault occurrences, dates/times, and any external events (power cuts) to help with diagnosis and when dealing with the engineer or manufacturer.