Potterton boiler fault codes
Potterton boilers are built by Baxi Heating UK, and since 2023 the Potterton website has forwarded to baxi.co.uk, so an owner searching for help lands on Baxi pages that never mention their badge. The manuals do still exist, and they are what these pages are written from: the Promax, Titanium and Gold guides for the boilers with a rotary switch, the Assure and Promax Ultra guides for the ones with a proper digital display, and the Heat-only manuals for the ranges that flash a light instead. The platform under the casing is shared — a Potterton Assure and a Baxi 600 are the same appliance with different badges — but Potterton documented every range in its own name, and where a Potterton manual says something different from the Baxi one, this site follows the Potterton one. There is more variation between Potterton generations than between brands: E28 has had three different meanings on Potterton combis since 2007, and the code for low water pressure changed from E119 to E118 when the display changed. Find your display type below before you look up a number.
Where the code shows on a Potterton
Three systems, and the front of the boiler tells you which. A two-character window beside a rotary ON/OFF/RESET knob is the Promax, Titanium, Gold and Heatmax family (2007–2019): three-digit codes are shown in halves, "E1" then "33" for E133, and Potterton's guides spell this out because owners report E1 as the fault. A larger digital screen with a separate Reset button and a spanner symbol is the Assure Combi and System and the Promax Ultra (2015–2023): the code is a flashing number, 118 or 133, with a spanner when you cannot clear it yourself and an R when you can, and low pressure is 118 rather than 119. No display at all but an illuminated button that flashes green or red is a heat-only boiler — Assure Heat, Titanium Heat, Ultra Heat — where the count of red flashes is the code. Older heat-only Promax HE Plus, Promax SL and Gold Heat boilers have three small LEDs whose on/off/flash pattern is read against a table in the installer's manual; those and the Suprima's neon codes are described at the bottom of this page rather than given pages of their own.
How to reset a Potterton
Different for each display, and the hold time is not interchangeable. Rotary-switch boilers (Promax, Titanium, Gold, Heatmax): turn the selector knob fully anticlockwise against the spring to the Reset position and hold it there for at least five seconds — Potterton's wording in every one of those manuals — and only E110, E130 and E133 respond; E119 clears itself when the pressure is restored. Digital-display boilers (Assure, Promax Ultra): press the Reset button for one to three seconds according to the installation manual; the Assure user guide says approximately one second and warns that holding it for more than two seconds will not reset the boiler, so a long press is the wrong instinct here. The same user guide's flowchart says "press and hold for 5 seconds", which contradicts its own instruction two pages later; the one-to-three-second figure appears in every installer manual and is the one to trust. Heat-only boilers with the flashing button: hold Reset until the flashing speeds up and goes out, five seconds in the Ultra Heat user guide, and the boiler allows five resets in an hour before it must be powered off and on. On every range Potterton's advice after a reset that does not hold, or a code that comes back regularly, is the same: stop and contact your installer or Baxi Customer Support, which is who answers for Potterton now.
Most common Potterton faults
The Potterton codes people look up most.
- E119Get it checkedThe sealed system on a rotary-switch Potterton — Promax, Titanium, Gold, Heatmax — has dropped below half a bar. The window shows E1 and then 19. Fill to 1–1.5 bar and it clears itself.
- E133Get it checkedGas supply interrupted, ignition failed or no flame detected — every Potterton generation. Confirm the gas supply, one reset (5 s on the knob, 1–3 s on the button), and call if it returns.
- E118Get it checkedThe digital-display Pottertons — Assure Combi, Assure System, Promax Ultra — have dropped below half a bar on the heating circuit. Repressurise to 1–1.5 bar and the boiler restarts on its own.
- E110Get it checkedSafety thermostat operated — the primary water overheated — on every Potterton code display. One reset is permitted (5 s knob or 1–3 s button); a second E110 is a circulation fault for an engineer.
Every Potterton fault code
28 published codes. Filtering happens in the page — every one is in the HTML.
Showing 28 of 28 codes
Potterton models
Codes can differ between generations. Check yours.
- Assure Combi and Assure System2019–2023
- Assure Heat, Titanium Heat and Ultra Heat2016–2023
- Gold Combi HE, Gold Combi HE A, Gold Combi and Gold System2007–2019
- Profile, Kingfisher, Netaheat, Performa1985–2011
- Promax Combi HE Plus, HE A and Promax Combi 24/28/332008–2019
- Promax HE Plus, Promax SL, Promax FSB, Gold H and Gold Heat2008–2019
- Promax Heatmax HE2012–2014
- Promax Store HE and Promax Store2011–2016
- Promax System HE Plus, HE A and Promax System 12–322008–2019
- Promax Ultra Combi2015–2019
- Suprima and Suprima HE1997–2008
- Titanium Combi2012–2017
Guides that help with Potterton faults
Boiler fault codes explained: what they actually tell you
Codes look like diagnoses and are not. Understanding which family a code belongs to turns a meaningless number into a genuinely useful starting point.Read the guideHow to repressurise a boiler
The five-minute job that resolves more no-heating calls than any other. Here is how to do it properly, and how to tell when topping up is the wrong answer.Read the guideWhat a Gas Safe engineer actually checks in a boiler service
Most people pay for this once a year and stand in another room while it happens. Here is what should be going on, which test cannot be faked, and how to tell a real service from twenty minutes and an invoice.Read the guideWhat to do when your condensate pipe freezes
The single most common winter boiler fault, and one of the few you can genuinely fix yourself in fifteen minutes with a kettle and some patience.Read the guide
Looking for Potterton’s own support? www.baxi.co.uk. We are not affiliated with Potterton.