Potterton [E133] fault codewhat it means and how to fix it

E133 is the one code every Potterton manual since 2007 defines identically — gas supply interrupted, ignition failed, or flame not detected — and it is also the code Potterton give the owner the most to do about. The Promax, Titanium and Gold user guides tell you first to "ensure that the gas supply has not been turned off", then to turn the selector to Reset and hold it for at least five seconds, and to call your installer or service engineer if the boiler does not relight or the code keeps coming back.

On the Assure and Promax Ultra the display shows 133 with an R beside it, meaning you may reset it — a press of one to three seconds in the installer manual, about a second in the user guide — and the Assure user guide adds the prepayment meter to the list of things to check first. The install manuals describe what the boiler did before showing it: sparking at the electrodes for up to five seconds, three attempts, no flame confirmed. The installer's fault-finding sections then run through gas at the burner, 230 V to the gas valve, the electrode and its lead, spark gap and position, and finally the PCB.

The pattern that matters to an owner is timing. A Potterton that shows E133 on a frosty morning and lights by lunchtime has a frozen condensate pipe, which the Assure user guide names in its troubleshooting table: "Condensate drain blocked. Check drain, especially any external runs in freezing temperatures." One that fails every morning regardless of weather has an ignition component on the way out. One that fails and cannot be reset has no gas or a failed valve, and that is where you stop.

1. 1

   Check the gas is on: try the hob or another gas appliance, and check the meter for credit or an emergency control valve that has been closed.

2. 2

   In freezing weather, find where the small plastic condensate pipe leaves the house. If it runs outside, pour warm water along it and over the outlet until it drains; never use boiling water on plastic pipe.

3. 3

   Reset once. Rotary knob: turn it fully anticlockwise to Reset and hold for at least five seconds, then release. Assure or Promax Ultra: press Reset for about a second — the Assure guide says holding more than two seconds will not reset.

4. 4

   If the boiler lights and stays lit, you are done. If E133 returns the same day, or comes back regularly, stop resetting and contact your installer or Baxi Customer Support — Potterton's own instruction.

   Do not keep resetting a boiler that will not hold a flame. Each attempt admits gas to a burner that is not lighting it.