BAXI Boiler Problems & Troubleshooting

BAXI boilers are highly regarded for their efficiency and reliability, but like any heating system, they occasionally face issues. Understanding the fault codes displayed on your BAXI boiler can help you diagnose and, in some cases, resolve issues quickly, saving both time and money.

Below, we’ve compiled a guide to the most common BAXI boiler error codes, what they mean, and practical troubleshooting tips to get your boiler running smoothly again.

Note: Always consult a qualified engineer for repairs beyond basic troubleshooting. Working with boilers can be hazardous without the proper expertise.

Understanding BAXI Boiler Error Codes

BAXI boilers use a digital display to show error codes when there’s a problem. These codes make diagnosing issues easier and indicate whether a problem is minor (like low pressure) or serious (like a gas supply issue). Let’s break down the most common error codes and troubleshooting tips.

Common Baxi Boiler Error Codes

Baxi Boiler 110 Error Code

In houses with older, traditional radiator heating systems, you are more likely to see Error Code 110. This simply means your boiler has overheated.

Suggested fix

Firstly, attempt to bleed your radiators. This simply means you’re letting any trapped air in the radiator out.

Not only does air in your heating system result in your entire system being inefficient, but it can stop the boiler from doing its job and overheating.

In more modern houses with underfloor heating, this is less likely to be an issue, but it can still happen.

Baxi Boiler E119 Error Code – Low Water Pressure

Cause: The water pressure in your heating system has dropped below the required level.

Symptoms: Heating shuts down, and the display shows E119. Radiators may also feel cool, especially at the top.

Fix:

1. Locate the pressure gauge on your boiler. Ideally, it should read between 1 and 1.5 bar.
2. If it’s below 1 bar, use the filling loop (usually a silver hose beneath the boiler) to add water until the gauge reaches the recommended level.
3. Close the filling loop and reset the boiler.

Tip: If pressure drops frequently, there may be a leak in the system. Contact an engineer for further inspection.

Baxi Boiler E125 Error Code – Overheat Fault

Cause: The boiler has detected excessive temperatures, often due to poor water circulation.

Symptoms: Boiler shuts down to prevent damage, and you see E125 on the display.

Fix:

1. Check for airlocks in the radiators by bleeding them.
2. Ensure that all radiator valves are open to allow water flow.
3. If this doesn’t resolve the issue, it could indicate a pump issue, which needs professional assistance.

Baxi Boiler E133 Error Code – Ignition Failure or Gas Supply Issue

Cause: Either the boiler cannot ignite, or there’s an issue with the gas supply.

Symptoms: Boiler attempts to start but fails. You may hear clicking sounds or see the E133 error on the display.

Fix:

1. Confirm that the gas supply is on. Check other gas appliances (like a hob) to see if they’re working.
2. If your gas supply is working, try resetting the boiler.
3. If the error persists, there could be an issue with the ignition components or flame sensor, which requires professional attention.

Baxi Boiler E160 Error Code – Fan Fault

Cause: A problem with the boiler’s fan, which is essential for venting gases safely outside.

Symptoms: Boiler may not start or shut down unexpectedly, and you’ll see the E160 error code.

Fix:
This issue is best left to a qualified engineer, as fan replacements or repairs involve working within the boiler casing.

Baxi Boiler E199 Error Code – Low Boiler Pressure

This error code means your water pressure is low. The normal water pressure for a Baxi is between 1.0 and 2.0 bar.

Suggested fix

You may need to check your gauge and note if the water pressure is less than 1.0 bar. It is not uncommon for boilers to need to be repressurised and in most cases, you can do this yourself.

Some people use rigid filling loops, flexible filling loops or an Easy-Fill permanent filling link.

Recommended reading: Boiler Filling Loop: Installation, Repair & Replacement

If this isn’t something you have or know how to use, we recommend you call an engineer to top up your Baxi boiler’s pressure.

Baxi Boiler E168 Error Code

When your Baxi boiler has an issue but cannot work out where the problem is, it will show this error. The most common cause for seeing this code is when there is a problem with the electrical supply (PCB lockout error).

Suggested fix

If your power is running fine to the rest of your house, you will need a registered Baxi engineer to diagnose the fault.

Additional BAXI Error Codes and Their Solutions

To give you a complete guide, here are some other common BAXI boiler error codes and their solutions:

E20 – Central Heating Thermistor Fault

• Fix: Thermistor issues typically require a part replacement, so an engineer should be consulted to replace this component.

E28 – Flue Sensor Fault

• Fix: Check that the external flue isn’t blocked by debris or snow. If clear, call a technician to inspect the sensor.

E50 – Hot Water Outlet Thermistor Fault

• Fix: This error is best handled by a professional, as it involves replacing the hot water sensor.

E110 – Overheat Protection Triggered

• Fix: Turn off the boiler and let it cool. Ensure that the area around the boiler has proper ventilation. Recheck after a reset.

E131 – PCB/Internal Error

• Fix: PCB issues are complex and often require a replacement, which should only be performed by a certified engineer.

E133 (Alternative Cause) – Ignition Lockout

• Fix: Reset the boiler and check the flame sensor and wiring for any obvious issues. Contact an engineer if the error persists.

E146 – Flue Temperature Overheat

• Fix: Ensure flue vents are clear. This issue usually requires an inspection by a heating professional.

E193 – Circulation Fault (Pump Issue)

• Fix: Inspect for blockages in the system, or bleed radiators to eliminate air. A pump replacement may be necessary.

E117 – High Water Pressure

• Fix: Release pressure by bleeding a radiator. If this is a recurring issue, it might signal a faulty expansion vessel that requires repair.

Common Baxi Boiler Fault Lights

Green Flashes

In many cases, green flashes do not require a fault-finding process and you can usually allow your boiler to continue as normal.

1 green flash simply means your boiler is up to the temperature you requested.

3 green flashes means the flame went out. If this is a temporary issue, the boiler should reset by itself. If it cannot fix this it will turn into 3 red flashes (see red flashes and also see how to manually reset your boiler below).

4 green flashes means there has been another temporary error that should be sorted with a self-reset. 4 green flashes are indicative of a communication error between PCB and Control.

5 green flashes, as above, can be fixed by the boiler self-resetting. This fault means there has been a parameter error on PSU/PCB.

6 green flashes is also a temporary error that is fixed by a self-reset however, the cause for the fault is unknown.

Red Flashes

1 red flash means there could be temperature, sensor or flow faults. You will need an engineer to locate the issue.

2 red flashes is a sign your boiler has overheated. Try bleeding your radiators before calling an engineer.

3 red flashes, as discussed above, means your ignition is failing to light and that your boiler has self-reset 5 times and is still facing the same issue. Unfortunately, some Baxi boiler models can be prone to this fault and you may need to replace chamber seals if they have worn or degraded over time.

4 red flashes are indicative of issues with your fan. If the fan isn’t working correctly, it may not be pushing flue gases out away from the flue. It is integral you call an expertly trained engineer to ensure your fan is replaced.

5 red flashes is a parameter or PSU error that cannot be fixed by a self-reset. Call an engineer to help you locate the issue.

6 red flashes is an unknown error. You will need an engineer to help fix this.

Did you find these common error codes and fault lights helpful?

If not, try these common troubleshooting Q&A’s that we’ve got below.

Other Common Baxi Boiler Questions

How do I reset my Baxi boiler?

If in doubt, always try this first so that you don’t call an engineer out for no reason. It’s easy to do.

Simply hold the reset button for a minimum of 5 seconds and then release it. If the process is successful your boiler will reboot and begin operating as normal.

If you find yourself doing a manual reset regularly, you may need to call an engineer and explain the situation.

Baxi boiler no hot water/heat

Unfortunately, there are a variety of problems that could cause this fault in your boiler, so you’ll need to get an engineer out to locate the issue.

Recommended reading: No Hot Water from Boiler: Our Ultimate Troubleshooting Guide

An engineer will be looking for broken parts such as diaphragms or airlocks.

They will also check valves and any motorised valves which may have failed as well as your thermostat and water pressure.

My radiators aren’t getting hot

When there is a build-up of debris inside the heating system (in such cases a central heating power flush is highly recommended) or if a lot of air is trapped, you’ll get a very inefficient system and/or an unequal heat distribution throughout the various radiators.

If you don’t know how to bleed a radiator yourself you can get an engineer out, otherwise, this is something you should be able to fix on your own.

Should my Baxi boiler be making loud noises?

You should always be listening out for your boiler and if it starts making unusual noises such as gurgling, banging or a high-pitched whistling, there are possible issues with the water pressure or air in the system.

You can try repressurising if you’re comfortable with the instructions noted above, or you can call an engineer straight away.

What is kettling?

Kettling is another noise you could hear with your boiler and it’s very similar to the noise a traditional kettle makes as it heats up – hence the name.

This is caused by a build-up of debris or limescale inside the boiler and sometimes it can be fixed but often the parts need replacing.

I think my Baxi boiler is leaking

If you ever notice your boiler dripping you need to call an engineer. The most likely culprit will be a broken or heavily deteriorated part.

The engineer will start by checking the area the leak is coming from and they’ll let you know if a component is going to need replacing.

Why is my Baxi boiler switching itself off?

Once again, this is the sort of fault that can be hard to pinpoint on your own.

A qualified engineer will be able to run a variety of tests that can look at your water pressure, valves, thermostat and water flow to check what is causing this boiler fault.

My Baxi boiler pilot light has gone out

You’ll need an engineer here as it’s most likely your thermocouple has broken and the component will need replacing in order to get gas into your boiler.

You may need to replace parts so we recommend having an engineer out for this one.

Recommended reading: Boiler Pilot Light Out: How to Relight Pilot Light on Boiler

I’m continuously losing pressure in my Baxi boiler

Did you recently bleed your radiators? If so, it can commonly cause boilers to lose pressure momentarily.

Keep an eye on it and it should come back. If not, you’ll need to do some checks and ensure there are no water leaks in the system.

If there are, you’ll need an engineer. If there aren’t, you may just need to replace the pressure relief valve.

I’m having thermostat issues with my Baxi boiler

If there aren’t any clear issues with your thermostat and it’s definitely switched on properly (i.e. this isn’t just a user error), then you may need to replace the thermostat, which may require help from a professional.

My Baxi boiler keeps locking out

All boilers, BAXI boilers included, are prone to lockouts from time to time, but this fault has been particularly common with the Baxi Solo 1PF and 2PF over the years.

The root of the problem comes from the boiler overheating. The boiler locks out to preserve any internal components and further damage.

This is not easy to diagnose without fault codes. Asides from leaks, there are other problems that can cause a boiler to lock out including fault codes: 110 (overheating), to 160 (a faulty fan) or even 166 (air pressure switch fault).

A common culprit for this fault on Baxi boilers is a lack of pressure. If your system is set lower than 1.5 bar then it won’t operate correctly.

Now, the quick fix is to top up the pressure using the filling loop.

Once you’ve topped up the pressure, you’ll need to reset the boiler. On the Baxi 1PF you’ll see an orange button. On the 2PF there will be a red button. These buttons will reset the boiler and get it up and running again.

But here lies a problem. The boiler has lost pressure. And that means there is a problem that needs to be fixed.

Most Baxi boiler faults where the system has lost pressure are because of leaks in the system.

You can do some visual checks to try and isolate the problem. Check for leaks on:

• Radiators
• Towel rails
• Pipework
• Radiator valves
• Beneath the boiler (this could be the pump)
• The expansion vessel

Tips for Preventing Common BAXI Boiler Faults

Keeping your boiler well-maintained can help avoid many common faults:

• Check pressure regularly to ensure it stays between 1 and 1.5 bar.
• Bleed your radiators annually to remove trapped air, improving efficiency.
• Schedule annual servicing with a Gas Safe registered engineer for thorough inspection and cleaning.

Understanding your BAXI boiler’s error codes and troubleshooting basic issues can save you time and prevent minor problems from escalating. However, for complex repairs or recurring faults, professional help is essential to ensure safety and efficiency. Get in touch with PHS Engineers for expert BAXI boiler support, and enjoy peace of mind knowing your heating system is in capable hands.