Worcester C1 Installation And Servicing Instructions page 51

The appliance can be reset by pressing the reset button and
holding in for 5 seconds when the appliance has cooled.
IGNITION LOCKOUT
The appliance will enter a lockout condition in the event of the
burner failing to ignite.
If the burner fails to light after 5 attempts the electricity supply
to the gas valve will be interrupted.
If ignition lockout has occurred, the central heating demand
indicator will flash slowly (approximately once per second).
The appliance can be reset by pressing the reset button and
holding in for 5 seconds. Check that the gas supply has not been
interrupted.
If this condition continues to occur, then call a service engineer.
AIR FLOW DEVICE
The appliance will enter a lockout condition in the event of an
air flow fault.
If the controls fail to detect the correct air flow through the
appliance the electricity supply to the gas valve will be interrupted.
If an air flow fault has occurred, the domestic water demand
indicator will flash (approximately five times per second).
The appliance will try to re-light after a waiting period of
approximately 4 minutes Check that the flue terminal has not been
obstructed or damaged.
If this condition continues to occur, then call a service engineer.
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