BoilerFaultCodesIdeal 86 Fault Code
The Ideal 86 fault code means: your boiler has stopped working because the water pressure inside your heating system has dropped too low.. It appears on 1 Ideal model in our database.
Technical description: Low system pressure indicated on pressure gauge
DIY fix possible
Locate the external filling loop (a silver flexi-hose) near the boiler.Open the valves at both ends of the loop to allow water into the system.Monitor the pressure gauge on the front of the boiler until it reaches 1.5 bar, then firmly close both valves.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Ideal models that show the 86 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal 86 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