Error E317

Safety precautions:

- Do not open the boiler casing or attempt internal repairs yourself. Live voltages and gas components are hazardous.

- Turn off the electrical supply to the boiler at the isolation switch or consumer unit before touching any external wiring or testing the supply.

- If you suspect gas smell or other gas safety issues, turn off the gas supply at the meter or isolation cock and call your gas supplier or a Gas Safe registered engineer immediately.

Initial checks a homeowner can safely do:

1. Check the boiler display and note the exact error code and any subcode or blinking behavior. Take a photo for the engineer.

2. Press the boiler RESET button once. If nothing happens, switch off the boiler at the isolator for 30 seconds and switch it back on and try again. If the fault returns, do not keep resetting repeatedly.

3. Ask whether the property is being supplied from a generator, inverter, UPS, or an alternative power source (for example during power outages, solar hybrid systems, or temporary generator use). If yes, stop using that supply and put the boiler back onto the normal mains supply.

4. Check for recent electrical work or power events. Have any new inverters, battery systems or temporary generators been installed recently?

Diagnostic and further checks (only if you are competent and comfortable with simple electrical checks):

1. Confirm the boiler rating plate or manual shows the required mains frequency (usually 50 Hz). Do not open the boiler casing to find it; the plate is often on the boiler outer case.

2. If you have a mains voltage and frequency meter and know how to use it safely, measure the incoming supply at a fused spur or socket on the same circuit (with the boiler powered down and isolated first, then power restored for the test). Check that the voltage is within normal range and that the frequency is the correct value (50 Hz in the UK). If you are not experienced with electrical testing, do not attempt this.

3. If the frequency reads incorrectly or is unstable, stop using the source and contact a qualified electrician immediately. Do not run the boiler on a supply that is the wrong frequency or has a modified waveform from an incompatible inverter or generator.

What to tell the professionals and next steps:

- If the fault persists after a reset and the supply frequency or waveform is suspect, arrange for a qualified electrician to check the incoming supply, the consumer unit, and any alternative power equipment (generator, inverter). The electrician can measure mains frequency and waveform and correct the supply or reconfigure the generator/inverter to provide a stable 50 Hz output.

- Arrange for a Gas Safe registered heating engineer to inspect the boiler. Provide them with the error code (E317), the circumstances when it appeared (e.g. after switching to a generator or after a power cut), measured voltage and frequency if available, and any repeated fault behavior. The engineer will check the boiler electronics and replace or repair any damaged components such as the PCB, fan, or controls if needed.

Final notes and warning:

- Do not continue to operate the boiler if you know the supply frequency is incorrect. Running on an incompatible supply can damage the boiler and create unsafe conditions.

- This fault generally requires involvement of both an electrician and a Gas Safe registered heating engineer. Call professionals rather than attempting internal repairs yourself.