Ideal Flue Thermostat Mini HE 173985

The Ideal 173985 is a flue thermostat used on Ideal Mini HE boilers. It sits on the flue path and monitors the temperature of the flue, interrupting the appliance's operation when the flue runs hotter than it should. The flue itself is the vent that carries steam and combustion gases safely away from the boiler, and its condition directly affects how the appliance runs.

• The boiler locks out or shuts down shortly after firing, with the fault clearing only after the appliance has cooled.
• Repeated overheat trips or flue-related fault codes appear on the appliance.
• Operation is intermittent, with the boiler running normally on some cycles and cutting out on others.
• The boiler will not restart until it has been manually reset.
• The thermostat body, capillary or wiring shows signs of heat damage, corrosion or a poor connection.

• Check the GC number on the appliance data badge against the numbers listed above to confirm the boiler variant.
• Confirm the appliance is a Mini HE C24 or C28 before ordering, as the flue thermostat is matched to the flue arrangement on these models.
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.