The Ideal Mexico Super is a mains gas regular boiler. Below are the faults it most often develops, what the error codes mean, and how to get it fixed at a fixed price by a Gas Safe registered engineer.
Variants covered: 40FF, 50FF, 60FF, 70FF, 80FF, 100FF, 125FF, CF3/40, CF3/50, CF3/60, CF3/100, CF3/125, CF3/140, CF3/70, CF3/80, RS3/40, RS3/50, RS3/60, RS3/100, RS3/70, RS3/80, RS3/125, 4125 FF, 4100 FF…
The gauge drops below ~1 bar and the boiler cuts out — usually a small leak, a tired expansion vessel or a weeping pressure-relief valve.
It tries to light, fails and locks out — often the spark electrode, gas valve or a flame-sensing fault.
Drips or staining under the case — a seal, the pump, the heat exchanger or a corroded pipe.
Rumbling on the heat exchanger, usually limescale or sludge restricting flow.
Cool rads or slow warm-up — often the pump, a sticking motorised valve or air in the system.
These are the likely causes — a Gas Safe registered engineer confirms the fault on site before any work. If you can smell gas, stop and ring 0800 111 999.
If there's a code on the display, tap it for the meaning, the free checks to try first and a fixed repair price:
One fixed price, no callout fee, a vetted Gas Safe engineer who covers your postcode.