Baxi Megaflo Fault Codes
The Baxi Megaflo System is Baxi's system-boiler range, named for its natural pairing with the Heatrae Sadia Megaflo unvented cylinder (same Baxi Heating family) in homes wanting stored hot water and strong shower performance. It runs the platform E-code scheme: E119 low pressure, E133 ignition/gas supply, E110 overheat, and the standard sensor, fan and circulation codes. The system-boiler context shapes the diagnosis. Hot water problems may belong to the cylinder, its controls or its immersion rather than the boiler — no boiler code but no hot water usually means look at the cylinder side — while boiler codes here concern the sealed heating circuit the boiler manages. The codes below link through to their full cause-and-fix pages.
Where Megaflo fault codes appear
The Megaflo System shows E-prefixed codes on its fascia display when a fault trips. Because system installations split duties between boiler, cylinder and external controls, note where the complaint actually is: a code on the boiler display is a boiler fault; silent boiler plus cold cylinder points elsewhere.
Resetting a Baxi Megaflo
Press and hold the reset control briefly; the boiler retries. E119 wants the heating circuit topped up to 1–1.5 bar first — the filling loop is at the boiler, not the cylinder. Unvented cylinders themselves are not DIY territory: their safety controls require a G3-qualified engineer, so hot-water-side faults belong with a professional visit.
Common Megaflo problems
Megaflo System installs mostly log the platform staples — E119 pressure loss, E133 winter ignition faults — plus motorised-valve and external-control issues that present as heating-works-hot-water-doesn't (or vice versa) without any code at all. Sludge matters doubly here, as system boilers often drive older radiator circuits; a magnetic filter and inhibitor keep the E125 circulation codes away.
Most common Megaflo fault codes
- E119 The E119 fault code indicates that your boiler's system pressure has dropped below 0.5… Read more →
- E133 E133 on a Baxi boiler is a gas supply or ignition lockout: the boiler tried to light its… Read more →
- E110 The E110 code means your Baxi boiler's safety thermostat has detected that the primary… Read more →
- E125 The E125 code tells you that the boiler's PCB has detected a problem with primary water… Read more →
- E160 The E160 code on a Baxi boiler indicates a fan fault. Specifically, the boiler's control… Read more →