Ideal Heating · Logic Code Combi ESP1
FUFlow/return differential greater than 50°C
This code applies to Logic Code Combi ESP1 26, Logic Code Combi ESP1 33, Logic Code Combi ESP1 38. Fault codes narrow down the likely problem, but they do not replace a model-specific diagnosis.
What you can safely check
- Check the system pressure and make sure accessible radiator valves are open.
- Allow an overheated boiler to cool and reset once only if the user manual permits it.
- If the fault returns, stop resetting and arrange an engineer.
How an engineer may fix it
Diagnose water circulation, air locks, pump operation, valves, bypass, blockages, heat exchanger and temperature sensors; restore correct flow and test the safety controls.
Manufacturer source: Ideal Heating — Logic Code Combi ESP1 Installation & Servicing (UIN 222364 A04). Checked 15 August 2026. The appliance manual and an engineer’s on-site diagnosis take precedence. Never remove the boiler case yourself.