00 fault on Ideal Logic boiler

00 fault on Ideal logic
00 fault on 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
  • Heating timer turned off
  • Summer winter selector switch turned to summer
  • No hot water demand.

Room thermostat set too low:

The heating will only come on if the room thermostat is set above the current room temperature (a demand).

If you always keep your room thermostat at 20oC and the room temperature is 23oC (for example in the summer or if the heating has been running for a long time) the heating will not turn on. As soon as the room temperature drops to below 20oC there will be a demand and the heating will operate.

Room thermostat set at 30oC
Room thermostat set at 30oC

The thermostat in the picture above is set at 30oC so the heating will operate until the room is above that temperature.

Room thermostat set at 10oC
Room thermostat set at 10oC

The thermostat in the picture above is set at 10oC so the heating will not operate until the room is below that temperature. As the temperature is set very low the heating will only very rarely come on. This is the type of situation where 00 would be displayed on the boiler.

Beware that not all thermostats look like this. Some are digital, some have dials that turn in the other direction and others are a mixture of timer and thermostat.

Your thermostat may have a battery in it that can run out. If you aren’t sure a wireless battery powered thermostat always has a receiver in the boiler or on the wall near the boiler. Check to see if there is a battery compartment on the wall thermostat and replace the batteries.

Heating timer turned off

In order for the heating to work the thermostat must be turned up and the timer must be turned on.

An example of a mechanical timer
An example of a mechanical timer

The picture above is of a mechanical timer (from an Ideal Logic) that is turned to constantly on.

The circular switch at about 9 o clock can be moved up and down to select: always off, timer or always on. The selector switch is currently set to always on. If the round switch was pushed up the heating would never come on. If the switch was moved to the middle it would only come on at the times set on the timer.

Summer winter selector switch turned to summer

Ideal Logic boilers have a power selector switch with three options.Boiler off far left, hot water only in the middle and heating and hot water on far right. This is a throwback to when thermostats and timers were not as common. In the summer you would turn the heating off at the boiler. In the winter you would turn it back on again at the boiler.

Hot water only mode will create a 00 fault on an ideal logic when using the heating
Hot water only mode will create a 00 fault on an ideal logic when using the heating

When you have the switch set to hot water only the heating will not work. The thermostat and timer are disabled so turning them up or down will have no effect.

No hot water demand

Inside the boiler there is a small propeller (flow turbine) that turns when water flows through the boiler to the hot tap. This is how the boiler knows that hot water is required.

If the water is flowing too slow the boiler will not recognise the demand and will not fire.

If the water flow turbine is broken or clogged then it cannot turn and the boiler will not fire.

Summary

If an 00 fault is displayed on your Ideal Logic turn up the thermostat, turn on any timers or run a hot tap.

If the boiler still doesn’t turn on you’ll need to get a gas engineer or electrician to check you boiler or controls.

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