If your Baxi boiler keeps showing the E133 fault code even after resetting, it’s a clear sign that the issue hasn’t been resolved.
This is something we see regularly across Bolton and surrounding areas, especially when homeowners have already tried the basic fixes, but the fault keeps returning.
At this stage, the problem is no longer a simple reset issue. It’s a deeper fault within the boiler’s ignition or gas system.
This is something we see regularly across Bolton and surrounding areas, especially when homeowners have already tried the basic fixes, but the fault keeps returning. At this stage, the problem is no longer a simple reset issue. It’s a deeper fault within the boiler’s ignition or gas system.
On Baxi 600 and 800 combi boilers, the E133 fault code indicates an ignition failure. Your boiler goes through a highly coordinate startup sequence to light the burner safely:
Standard Boiler Startup Sequence:
The main gas control valve opens to allow fuel flow.
A high-voltage electric spark jumps to ignite the gas-air mixture.
The flame sensing probe registers current passing through the heat.
If any part of that process fails or is interrupted, the boiler will lock out for safety and display E133.
Resetting your boiler simply tells it to try the startup sequence again. It is a safety bypass. If the fault clears after a reset but then returns, it usually means:
“Many customers call us saying: ‘It works after I reset it… but then stops again.’ That’s a key sign of an underlying fault.”
Once you’ve ruled out simple issues like gas supply or frozen pipes, the problem is almost always internal. Here are the most common faults we diagnose on Baxi 600 and 800 models:
Once you’ve ruled out simple issues like gas supply or frozen pipes, the problem is almost always internal. Here are the most common faults we diagnose on Baxi 600 and 800 models:
Creates the physical spark that lights the gas. Over time, these parts wear out, become damaged, or fail to spark consistently, causing intermittent lockouts.
Even if your boiler ignites briefly, it must confirm the flame is active. If the flame sensor fails, the system shuts down for safety, triggering E133.
The PCB is the central control brain. If it develops a fault, electrical signals fail, ignition sequences break down, and fault codes appear randomly.
External Supply
Once you’ve ruled out simple issues like gas supply or frozen pipes, the problem is almost always internal. Here are the most common faults we diagnose on Baxi 600 and 800 models:
Resetting your boiler simply tells it to try the startup sequence again. It is a safety bypass. If the fault clears after a reset but then returns, it usually means:
“Many customers call us saying: ‘It works after I reset it… but then stops again.’ That’s a key sign of an underlying fault.”
Once the issue goes beyond basic checks, it involves gas-related components and internal electrical systems. These are not safe to work on without the correct qualifications. Internal gas components must only be handled by a Gas Safe registered engineer.
We regularly diagnose and repair E133 faults on Baxi 600 and 800 boilers across Bolton. Because we see this issue so often, we can:
We know the Baxi 600 brain intimately.
We carry replacement electrodes and
valves on the van.
Getting your hot water running in a single visit.
Tried the reset and it’s still failing? It could be a faulty gas valve or ignition electrode. We’ll have it firing again the same day where possible.
Transparent pricing. No hidden surprises..
If your Baxi is constantly showing E133, the internal components might be failing. An upgrade could save you £400+ a year on bills.
Boiler is over 10–15 years old.
Energy bills keep increasing.
Constant breakdowns or callouts.
Banging or whistling sounds
Cold spots around the house.
Yellow flame or pilot light issues.
Leaks or visible corrosion.
Lacks modern smart features.
Wider Coverage
Because we’re locally based in Bolton, we offer fast installation dates and reliable aftercare support, not a national call centre.
