BoilerFaultCodes F 0t
Room Thermostat Fault: Check Room Stat & connections
Ideal LOGIC SYSTEM2 Fault codes & diagnostics
27 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Gas 2022-present
GC Numbers 41-796-8541-796-8641-796-8741-796-8841-796-8641-796-88
Download the Ideal LOGIC SYSTEM2 manual
PDF
Versions & GC numbers
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
Severity at a glance
Each cell = one fault code. Hover to identify. 27 Unrated
Which version do you have?
The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 41-796-85 | LOGIC SYSTEM2 S15 | 2022–present |
| 41-796-86 | LOGIC SYSTEM2 S18 | 2022–present |
| 41-796-87 | LOGIC SYSTEM2 S24 | 2022–present |
| 41-796-88 | LOGIC SYSTEM2 S30 | 2022–present |
| 41-796-86 | LOGIC SYSTEM2 S18P | 2022–present |
| 41-796-88 | LOGIC SYSTEM2 S30P | 2022–present |
Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.
Just want the most common Ideal LOGIC SYSTEM2 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 27 documented codes
Tap any card for details
F 0U
Flow/Return Differential greater than 50 °C
F 01
Low Water Pressure
F 02
Flame Loss
F 02 or FN or LN
Flame Loss
F 03
Fan Fault
F 04
Flow Thermistor Fault
F 04 or L 04
Flow Thermistor Fault
F 05
Return Thermistor Fault
F 05 or L 05
Return Thermistor Fault
Showing 11–20 of 27
F 06
Outside Sensor Fault
F 07
Low Mains Voltage: Contact Electricity Provider
F 09
PCB Fault: Replace PCB
F 10
Spark Generator Fault: Check wiring, if OK replace spark generator
F 12
Pump Rotor Blocked: Clear blockage
F 13
Pump Fault: Check pump wiring, if OK replace pump
F 14
High Mains Voltage: Contact electricity provider
F 15
Pump Fault: Check pump wiring, if OK replace pump
F 16
Gas Valve Fault: Check gas valve wiring, if OK replace gas valve
F 17
Pump Fault: Check pump wiring, if OK replace pump
Showing 21–27 of 27
L 0C
Boiler lockout after 5 restarts within 15 minutes
L 0d
Ignition Lockout: Blocked Flue/Condensate
L 01
Overheat Lockout
L 02
Ignition Lockout
L 04
Flow Thermistor Fault
L 05
Return Thermistor Fault
L 06
Flame On Before Gas Valve On
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