Error 5 Green Flashes

Safety first:

1. If you smell gas, leave the property immediately and call the gas emergency number. Do not attempt any checks on the boiler.

2. Do not open the boiler casing or attempt repairs involving gas or live electrical parts unless you are a qualified engineer.

3. Turn off the electrical supply at the isolator and, if required for initial troubleshooting, switch off the boiler using the front controls first.

Initial homeowner checks you can safely perform:

1. Record the exact error (5 green flashes) and note when it started and any recent events (power cuts, storms, electrical work). This information helps the engineer.

2. Check the boiler display/LEDs and see whether the fault clears by itself after a few minutes. Temporary parameter errors often self-reset.

3. Attempt a controlled reset: use the boiler reset button or selector (hold for 5–10 seconds) following the user manual. If the boiler has an on/off isolator, turn the electrical supply off for 60 seconds and then back on to perform a power-cycle before restarting the boiler.

4. Check other simple system items: confirm the room thermostat and timer controls are calling for heat, check system water pressure at the gauge (aim for roughly 1–1.5 bar for most systems), and make sure external condensate and flues are unobstructed. Do not attempt to top up or service internal components unless you know how and the boiler is isolated electrically and gas-wise.

If the error persists (diagnostic steps for engineers / what to expect when you call a professional):

1. Provide the engineer with the fault code, history (power interruptions, recurring faults), and whether a reset or power-cycle was attempted.

2. An engineer will check incoming mains voltage and PSU supply rails for stability; intermittent low or high voltage can corrupt stored parameters.

3. They will inspect the PCB/PSU for signs of water ingress, corrosion, burnt components, swollen capacitors, or loose/cracked connectors and solder joints.

4. The engineer may attempt to reload or reprogram parameters, replace the parameter storage element (if separate), or replace the PCB/PSU if corrupted or faulty. They will also check for underlying causes such as wiring faults or intermittent shorts that could re-trigger the error.

5. If the fault is intermittent and cleared by resets, the engineer may advise monitoring and scheduling a service to prevent future lockouts; if persistent, replacement of the faulty board or PSU is commonly required.

Final advice and escalation:

1. If the 5 green flashes clear and do not recur, make a note and continue to monitor the boiler. Occasional transient faults after power disturbances are not uncommon.

2. If the code returns repeatedly, the boiler locks out to a red fault, or you notice other symptoms (no heating/hot water, unusual smells, visible damage), stop trying repeated resets and contact a Gas Safe registered engineer or authorised Baxi service agent.

3. When you call for a service, give the engineer the fault code, any actions you took, and the timing of events — this speeds diagnosis and repair.

4. Do not attempt internal PCB or PSU repairs yourself; these involve live electrical and gas components and should only be handled by qualified personnel.