Ideal Logic System IE Gen 2 fault F05
Return thermistor fault
Gas boilerWhat it means
Fault related to the return thermistor, requires diagnostic procedure in Section 4.9.
Likely causes
- Thermistor fault requiring replacement
- Faulty or failed return thermistor requiring replacement
Where to start
- Isolate and drain down the boiler
- Remove the clip from the pump housing and remove the thermistor
- Disconnect the electrical lead from the thermistor
The full answer, free
- 1 more check in order
- The readings and component tests from the manual
- How to put it right, step by step
- The manual page for this fault (page 49), right under the answer
Safety: Isolate gas and power before you open the case. If you have been into the gas side, do a tightness test, and a combustion and flue check before you hand back. Gas Safe (UK) or RGI (Ireland) work only.
From the Ideal manual for the Logic System IE Gen 2. Check the model on the data plate before you order parts.
Other Ideal Logic System IE Gen 2 fault codes
- F02Flame loss
- F03Fan fault
- F04Flow thermistor fault
- F06Outside sensor fault
- F09PCB fault
- F0DLow water flow / low water pressure
- F0TRoom thermostat fault
- F0UFlow/return differential greater than 50°C
- F10Spark generator fault
- F12Pump rotor blocked
- F13Pump fault
- F15Pump fault
- F16Gas valve fault
- F17Pump fault
- L01Flow temperature overheat lockout
- L04Flow thermistor fault
- L05Return thermistor fault
- L06False flame lockout (flame on before gas valve on)
- L0CRepeated restart lockout
- L0DIgnition lockout: blocked flue/condensate