Complete guide to Baxi Duo-tec, Platinum, 800 series and other boiler fault codes with troubleshooting advice
Baxi boilers display fault codes starting with 'E' on the digital screen when they encounter a problem. Find your code in our guide below to understand what's wrong.
Tip: Baxi error codes start with 'E' followed by numbers (e.g., E119, E133, E110). Note down the exact code shown on your boiler display.
| Code | Meaning | Quick Fix | If That Doesn't Work | DIY? |
|---|---|---|---|---|
| E119 | Low water pressure - system pressure has dropped below safe level | Check pressure gauge. Use filling loop to top up to 1.0-1.5 bar. Reset boiler. | If pressure drops repeatedly: leak in system, faulty expansion vessel, or PRV issue. | Yes |
| E125 | Primary circulation fault - inadequate water flow detected | Check pressure is adequate. Bleed radiators to remove air locks. | Pump failure, blockage in system, or faulty sensor. Engineer required. | Partial |
| E78 | Water pressure sensor fault | Check pressure level and top up if needed. Reset boiler. | Faulty pressure sensor requires replacement by engineer. | No |
| Code | Meaning | Quick Fix | If That Doesn't Work | DIY? |
|---|---|---|---|---|
| E133 | Ignition failure - boiler failed to ignite after attempts | Winter: Check for frozen condensate pipe - thaw with warm water. Check gas supply is on. | Gas valve, ignition electrodes, or PCB fault. Gas Safe engineer required. | Partial |
| E28 | Flame detection failure - flame lost or not detected properly | Check gas supply. Reset boiler. | Flame sensor, gas valve, or electrode issue. Engineer needed. | No |
| E168 | No flame signal detected | Verify gas supply. In winter, check condensate pipe. Reset boiler. | Ignition system fault requiring professional diagnosis. | Partial |
| Code | Meaning | Quick Fix | If That Doesn't Work | DIY? |
|---|---|---|---|---|
| E110 | Overheat protection - boiler exceeded safe temperature | Let boiler cool down. Check radiators are on. Bleed air from system. Reset after cooling. | Pump failure, blocked system, or faulty overheat stat. Engineer required. | Partial |
| E160 | Fan speed fault - fan not reaching required RPM | Reset boiler. Check flue terminal is clear externally. | Fan motor wearing out or wiring fault. Engineer needed. | No |
| E117 | High system pressure - pressure above safe limit | Bleed a radiator to release some water/pressure. Do not exceed safe pressure. | Faulty filling loop (not closing properly) or expansion vessel issue. | Partial |
| E131 | Flow thermistor fault | Reset boiler. | Faulty temperature sensor requires replacement. | No |
| E134 | Return thermistor fault | Reset boiler. | Faulty return temperature sensor. Engineer required. | No |
Most Baxi boilers can be reset by pressing the reset button. The location varies by model:
Warning: If the boiler locks out again immediately after resetting, do NOT keep resetting. This can damage components. Call a Gas Safe engineer.
Our Gas Safe registered engineers service all Baxi models across Harrow, London and surrounding areas.