H9 / L9 / HA Display
All these codes relate to overheating, and can be treated the same.
Systems for this boiler can be open vented (automatically filled from tank in roof) or sealed (has filling loop & pressure gauge)
If sealed system, components will most likely be in airing cupboard, What is the reading on the system pressure gauge if below 0.5 bar pressure needs to be topped using the filling loop by the user / installer.
This fault can occur if all radiators are fitted with TRV'S
Can the pump in the airing cupboard be heard working - if no contact installer
Attempt reset.
- If the display changes to
wait approx 30 min's to allow the boiler to cool, then try to reset again. During this period the fan will continue to run. ensure system pressure is above 1 bar(if applicable) and all TRV's are open during this period -
If the fault code remains : Engineer visit required