Look-up › Fault codes by maker
Baxi, Main and Potterton codes
Checked against its sources: Updated
Baxi error codes depend on which guide covers your boiler, and even E133 means a frozen condensate pipe in one Baxi guide and a gas or flame fault in another.12 Main and Potterton are listed separately, and no code is assumed to carry across brands.
- Covers
- Only the Baxi, Main and Potterton models named below, gas
- You
- Read the display, repressurise and bleed where your guide allows, and reset once by your guide's method if it shows the reset symbol or says you can.
- A professional
- Faulty components, a spanner symbol, a continuous red light, repeat faults, and anything behind the casing.
1 Baxi boilers
| Code or display | What the Baxi guide says | Which manual, page | What the Baxi guide lets you do |
|---|---|---|---|
| A.02.06 or H.02.07 | Boiler needs repressurising | 400, 600, 800 Combi 2 quick start p103 | Repressurise; guide points to a video, no figures |
| E.04.10 | Frozen condensate pipe | Quick start p103 | Guide points to a video, no steps |
| E118 | Boiler needs repressurising | Compact quick guide p21 | Repressurise; video only |
| E133 (Compact) | Frozen condensate pipe | Compact quick guide p21 | Video only |
| E133 (Platinum) | Gas supply interrupted, ignition failed or flame not detected | Platinum Combi (1/18) p82 | Don't turn the gas back on yourself if it's been shut: speak to your supplier or an engineer first. If it's on, hold reset at least 5 seconds; installer if regular |
| E20, E50 | Central heating NTC fault; hot water NTC fault | Platinum p82 | Note the code, contact installer |
| E28 | Flue NTC, air pressure switch, blocked flue, blocked condensate or wiring fault | Platinum p82 | Note the code, contact installer |
| E110 | Safety thermostat operated: primary water overheated | Platinum p82 | Hold reset at least 5 seconds; installer if it repeats |
| E119 | Water pressure switch not operated; primary pressure below 0.5 bar | Platinum pp3, 6, 82 | Repressurise with the Easy-Fill if fitted, otherwise ask the installer |
| E125, E160 | Primary circulation fault; fan or fan wiring fault | Platinum p82 | Note the code, contact installer |
| E130 | Flue NTC operated: flue overheated | Platinum p82 | Hold reset at least 5 seconds; installer if it repeats |
| E28, E53, E133, E119, E128 | May mean a frozen condensate pipe | Listed on the maker's website, not in a user manual read7 | Conflicts with Platinum p8 above, and the page's headings print some numbers differently: check with Baxi |
The Compact guide's file is named for the Duo-tec, but the document never names that boiler; its own Duo-tec guide wasn't obtained.1 For the 400, 600 and 800 Combi 2 only the short quick start was found.3 The user manuals read don't list other numbers; the Compact guide says a full list is in the installation and servicing instructions.1
2 Main Eco Compact Combi
All from the 7716571-04 guide, p21, except 312.4 Whether you may reset depends on the symbol shown: R can be reset with the button, the spanner can't.
| Code or display | What the Main guide says | Which manual, page | What the Main guide lets you do |
|---|---|---|---|
| 09, 15 | Gas valve connection cable; gas valve fault | p21 | By symbol |
| 20, 28, 40, 321 | NTC faults: central heating; flue; heating return; hot water | p21 | By symbol |
| 83 | Communication error | p21 | By symbol |
| 109, 125, 270 | Pre-circulation; primary circulation; dry-fire circulation fault | p21 | By symbol |
| 110, 130 | Safety thermostat operated; flue NTC operated | p21 | By symbol |
| 118 | Primary water pressure too low | p21 | Top up as on p18; by symbol |
| 128, 133, 135 | Flame failure; gas interruption or flame failure; gas interruption (internal) | p21 | Check other gas appliances and prepayment credit (p14); by symbol |
| 154, 160, 384 | Flow/return sensor test; fan or wiring; false flame | p21 | By symbol |
| 103, 104, 107, "Bat" | No meaning given | p21 | Contact installer or Baxi |
| 312 | De-aeration running, about 7 minutes: a function you start yourself | p19 | Wait for it to finish |
3 Baxi 600 Heat and Potterton Titanium Heat
These boilers flash a status light. Green means the boiler has a problem and is trying to resolve it; red means lockout. An orange flash at each heating demand is normal.5 Checked against the picture on 600 Heat p23; Potterton's section is the same page.6
| Flashes | Green: warning | Red: lockout |
|---|---|---|
| 1 | Temperature protection | Sensor error |
| 2 | Shutdown input | High temperature protection |
| 3 | Flame loss | Ignition fault |
| 4 | Communication fault | Fan fault |
| 5 | Parameter fault | Parameter fault |
| 6 | Miscellaneous | Miscellaneous |
4 How the reset works on each family
Quick start and Compact guide: hold 5 seconds.31 Platinum: selector to reset, hold at least 5 seconds.2 600 Heat and Potterton: RESET, minimum 5 seconds, no more than 5 times within one hour; a continuous red light means call.56 Main: press for about 1 second, and over 2 seconds will not reset, yet the flowchart on p14 of the same guide says 5 seconds, so check with Baxi.4 Try once, and for a gas smell go to the gas entry.
Sources
- Baxi Compact Quick Guide, user instructions, 7849761, file dated 25 May 2023 (filename says Duo-tec), Baxi read 3 November 2026.
- Baxi Platinum Combi 24, 28, 33, 40 User Guide, 7697821-01 (1/18), published by Baxi read 3 November 2026.
- Baxi 400 Combi 2.1, 600 Combi 2, 800 Combi 2 quick start guide, 7876395-01, file dated 26 June 2024, Baxi read 3 November 2026.
- Main Eco Compact Combi 25, 30 User Guide, 7716571-04, file dated 2017, Baxi Heating read 3 November 2026.
- Baxi 600 Heat User Guide, 7726861-01 (1/19), pp14, 23, Baxi read 3 November 2026.
- Potterton Titanium Heat User Guide, 7668906-06 (2/20), pp14, 23, Baxi Heating read 3 November 2026.
- What do Baxi error codes mean, Baxi FAQ page, not a manual read 3 November 2026.