Ideal L5: return thermistor fault (Logic) or too many resets (Exclusive 2)

Check these first, then call an engineer

L5 means different things on different Ideal models. On the Logic Combi it's a return thermistor fault, which Ideal's boiler faults FAQ describes as a problem with the return. On the Exclusive 2, and in Ideal's general fault code guide, it means the boiler has been reset too many times in a short period (five resets in 15 minutes). Ideal's advice for both is the same first step: turn the power off and on.

What you can safely do

1. Turn the electrical supply to the boiler off for a few seconds, then back on, as Ideal advises.

Call a Gas Safe engineer if

• The boiler still won't work. Contact Ideal if it is under warranty, or a Gas Safe registered engineer.

Applies to: Logic Combi (ESP1), Exclusive 2. Codes can differ between models, so check your manual.