BoilerFaultCodesIdeal 9.1.9 Fault Code
Also written as 919 — same fault.
The Ideal 9.1.9 fault code means: your heat pump has stopped working because water is not moving through the outdoor unit properly.. It appears on 1 Ideal model in our database.
Technical description: Outdoor Unit, No Water Flow, Error
What causes the Ideal 9.1.9 fault?
This fault occurs when the system detects that water isn't moving through the outdoor unit at the required speed to safely exchange heat. The most common reasons are a build-up of debris or sludge blocking the internal filter, a failure of the main circulation pump, or trapped air pockets within the pipework. When the water stops moving, the unit shuts down to prevent the refrigerant system from overheating or freezing.
DIY fix possible
Check that your central heating pressure gauge is between 1 and 1.5 barEnsure all radiator valves and isolation valves are fully openCheck the outdoor unit for any obvious obstructions or debris
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Ideal models that show the 9.1.9 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal 9.1.9 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