Baxi Boiler e133 Error Code and its Solutions


The E133 error in the Baxi boiler (which in some manuals is simply called Error 133) indicates a repeated problem with the ignition and is therefore an ignition error. There are several causes that can lead to this error. In this article, we will analyze the causes of error E133 in the Baxi boiler, as well as their solutions. We will also present a practical summary table of causes and solutions that will be very useful.

What is error 133?

The E133 error in the Baxi boiler is quite common in this brand. In the simplest cases, it is, so to speak, a routine error. It sometimes manifests itself when the boiler has not been used for a season (after summer or vacations, for example), and its seasons of most use are about to begin: autumn and winter.

Then it happens that when we try to turn on the boiler, after several unsuccessful ignition attempts, it locks up and shows the error message 133 on the display. Depending on the model, the display can show the complete number 133, or divide the code in two, and display the first E1 and then 33, that is, E133.

In any case, according to the manual, the Baxi boiler can be restarted up to 5 times. After this, if the ignition is not achieved, the appliance locks up and displays error 133. (If you need to download a Baxi boiler manual, click or tap on this link to the brand’s official website.)

In both the old and modern models, the error E133 in the Baxi boiler also indicates a possible fault in the gas supply. The reasons for gas failure can vary:

  • Air has got into the gas circuit (this is most common during start-up at the end of the heating season).
  • The gas regulator is faulty or it is not the one that corresponds to the type of gas used by the boiler, so the equipment does not have enough gas to ignite.
  • The cable that connects the control panel with the ignition electrode has no continuity or has a short circuit.
  • The gas tank tap is closed, and we haven’t noticed this.

In cases of error E133 in a Baxi condensing boiler, these two other points must be added to the previous points:

  • The smoke recirculation mechanism is clogged and causes a smoke anomaly.
  • The condensate discharge pipe is clogged.

Table of solutions for Error E133 in the Baxi boiler

Let’s first see a summary table, which briefly exposes the possible causes for Error E133 in the Baxi boiler, with their respective solutions. After the table, we will go on to talk about some details about what the table only indicates, but only in the cases that really require details.

The boiler does not turn on after a relatively long time without it being used.It can be solved by resetting the boiler. But if air has got into the gas circuit, it must be purged.
The gas does not reach the burner because the inlet valve is closed or faulty.Open the gas tap. Lubricate or replace as appropriate.
The gas regulator is faulty or it is not the one that corresponds to the type of gas.Replace the gas regulator.
Lack of continuity in the cable between the control panel and the burner.Solve possible damage or short circuits in the cable.
Smoke anomaly during the calibration phase (in condensing boilers).Check if there is smoke recirculation, and activate the automatic calibration function.
The condensate discharge pipe is clogged (in condensing boilers).Uncover the condensate discharge pipe.

How to fix error 133 on the Baxi boiler? Details

The boiler does not turn on after a period of time without use

The most common solution for error 133 in the Baxi boiler is to restart (reset or rearm) the equipment. This will automatically resolve several of the causes of the failure. How do you reset a Baxi boiler? It’s very simple: press the Power/Reset key for 2 seconds, and then release it.

Up to 5 restart or reset attempts can be made. After the fifth attempt, error 133 will reappear, and you will have to wait 15 minutes before you can reset it again.

If resetting the boiler does not resolve error 133 in the Baxi boiler, it is possible that what is happening is that air has got into the gas circuit. This sometimes happens when we fill the gas tank. In these cases, it is recommended to purge the gas circuit.

NOTE: It is strongly recommended that the gas circuit is purged by a qualified technician, as it requires specific tools and special safety measures.


The gas isn’t reaching the burner and the boiler does not ignite

This seems like a very simple and unlikely cause, but it really does happen. If the boiler does not ignite, make sure that the gas inlet tap is open. Sometimes it gets locked without us noticing, especially after a season of inactivity. Do not rule out that the gas inlet tap may also be stuck or damaged, in which case it must be replaced.

Faulty or inadequate gas regulator

Each type of gas requires a specific gas regulator, except in the case of a multi-gas regulator. You must use the regulator that corresponds to the type of gas (natural or LPG). If you don’t have the correct regulator, then it has simply failed, so the solution is the same: replace it.

There is a smoke anomaly during the calibration phase

As we said above, the solution for when a smoke anomaly occurs during the calibration phase (due to a possible smoke recirculation), consists in checking if there is smoke recirculation, and activating the automatic calibration function.


Here are the steps to perform the automatic calibration function. If you notice that the valves we indicate do not match yours, check your manual to find out how to perform this procedure:

  1. Simultaneously press the On/Reset key and the heating reduction key for 6 seconds.
  2. When the display shows an “On” message, press the Information (i/P) key within 3 seconds of releasing the keys in the previous step.
  3. If at this moment the display shows a “303” message, this means that the automatic calibration function has not been activated. The boiler must be disconnected from the electrical supply for several seconds, and repeat the 2 previous steps.
  4. Once steps 1 and 2 are re-executed, the rest of the steps to activate the automatic calibration function will be carried out by the boiler on its own. If you want to know more details, check your manual or download a manual by following this link.

How to fix error 25 on the Baxi boiler?

Error 25 in the Baxi boiler (or error E25) indicates a lack of water circulation. This may be because the water circulation pump is blocked, or because the water circuit needs to be refilled. Filling the circuit is done by opening the water inlet tap. If instead the pump is blocked, it must be unblocked or replaced.


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