9.1.36 Medium

Ideal 9.1.36 Fault Code

Also written as 9136 — same fault.

The Ideal 9.1.36 fault code means: your heat pump’s automatic high-temperature disinfection cycle for your hot water tank failed to complete as scheduled.. It appears on 1 Ideal model in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: Anti-Legionella does not Operate

What causes the Ideal 9.1.36 fault?

This fault occurs when the system is unable to heat the water in your cylinder to the high temperature required to kill bacteria within the set timeframe. The most common reason is a failed immersion heater element or a faulty sensor that is incorrectly reporting the water temperature. It can also be triggered if the immersion heater has been manually turned off at the isolating switch, preventing the disinfection cycle from starting.

Typical repair cost £0-120 (including labour)

DIY fix possible

Check that your hot water cylinder immersion heater switch is turned on and hadn't tripped.Ensure hot water schedule allows enough time for the tank to reach 60-65°C.Restart the heat pump control panel to clear the temporary warning.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Ideal models that show the 9.1.36 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Ideal 9.1.36 fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026