What is a 00 fault on an Ideal Logic?

An 00 fault on an Ideal Logic isn’t a true fault but it’s still a problem I’ve been requested to fix.
OO is displayed on the front of an Ideal Logic boiler when there is no demand. For a combi boiler that is:
- Room thermostat set too low or faulty
- Heating timer turned off
- Summer winter selector switch turned to summer
- No hot water demand.