BoilerFaultCodesTechnical description
No link at ST2 Ls to Lr, or failed external control input to Lr. Failed programmer. Board fault.
What causes this fault?
This issue occurs when the boiler is ready to provide heat but is waiting for a command from your thermostat or timer that never arrives. The most common reason is a faulty room thermostat or a broken internal programmer that can no longer send an electrical signal to 'call' for heat. Because the boiler is working fine for hot water, the problem is almost always located in the external controls or the wiring that connects them to the main circuit board.
This fault often comes to light during the first cold spell of autumn when homeowners try to turn their heating on for the first time after the summer break.
DIY fix possible
Ensure your wall thermostat is turned up higher than the current room temperature.Check that your heating programmer or timer is set to 'ON' or 'AUTO'.Replace the batteries in your wireless room thermostat if it has them.