🕑 9 minutes read

Baxi boiler playing up again? You're not alone. These reliable workhorses can develop faults over time, leaving you without heating or hot water when you need it most. This comprehensive guide covers the most common Baxi boiler problems, error codes, and practical solutions to get your system running smoothly again.

Whether you're dealing with pressure issues, error codes, or complete system failures, we'll walk you through the troubleshooting steps and help you understand when to call in the professionals.

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First, Check Your Baxi Warranty

Before diving into DIY fixes, check if your Baxi boiler is still under warranty. All new Baxi boilers come with a minimum 2-year warranty, with warranties extending up to 10 years when installed by a Baxi-accredited installer.

Your warranty paperwork will outline the coverage terms, but please note that maintaining annual services is required to keep your warranty valid. If you're covered and the boiler has been serviced annually, most fault code issues should be covered under warranty.

For older properties where previous owners installed the boiler, you might not have the original paperwork. Don't worry, a qualified boiler engineer can still diagnose and repair most Baxi boiler problems efficiently.

Need help? Book a professional boiler repair in London with Serviceteam today.

Then Reset Your Baxi Boiler

Before calling an engineer, try the simplest solution first. Occasionally, Baxi boilers display fault codes in error or because they briefly detected an issue that didn't materialise. The fault code remains displayed until the system realises everything is actually fine.

Most Baxi boilers feature a reset button on the front panel. Here's how to reset your boiler:

  1. Locate the reset button on the control panel
  2. Press, then hold for 1-3 seconds
  3. Wait for the boiler to reboot completely
  4. Check if the error code has cleared

This simple reset resolves many temporary glitches and can save you an unnecessary engineer call-out.

Understanding Baxi Fault Codes

Baxi boilers display specific error codes to help identify problems quickly. These codes apply to Baxi 100, 200, 300, 400, and 600 combi models, as well as Baxi Duo-tec and EcoBlue combis.

Here are the most common fault codes and what they mean:

E117 Water Pressure Too High Your boiler pressure exceeds safe operating levels. Check the pressure gauge and manually reduce pressure if it's above 2.0 bar. Estimated repair cost: £50–£100.
E118 Water Pressure Too Low System pressure has dropped below 1.0 bar. Try repressurising the system yourself first. If the boiler pressure continues to drop, you likely have a leak that requires professional attention. Estimated repair cost: £50–£100.

Gas and Ignition Codes

E117 Water Pressure Too High Your boiler pressure exceeds safe operating levels. Check the pressure gauge and manually reduce pressure if it's above 2.0 bar. Estimated repair cost: £50–£100.
E118 Water Pressure Too Low System pressure has dropped below 1.0 bar. Try repressurising the system yourself first. If the boiler pressure continues to drop, you likely have a leak that requires professional attention. Estimated repair cost: £50–£100.
E133 Gas Supply Interrupted or Flame Ignition Failure Try resetting the boiler first. If the code persists, check that your gas supply hasn't been interrupted. This often resolves itself after a reset.
E134 Gas Valve Open Without Gas Similar to E133, this indicates timing issues with gas delivery. Reset the boiler and monitor for recurrence.
E135 Interruption of Gas Supply Try checking other gas appliances in your home to confirm if the gas supply is working properly. If they're not, contact your gas supplier. If only the boiler is affected, reset and monitor.

Boiler Component Failure Codes

E160 Fan Fault The boiler fan isn't working correctly, preventing safe operation. This requires professional repair. Estimated cost: £150–£200.
E20 Central Heating NTC Fault The Negative Temperature Coefficient sensor has failed. This needs professional replacement. Estimated cost: £200–£300.
E321 Hot Water NTC Fault Similar to E20 but affecting the hot water temperature sensor. Professional repair required. Estimated cost: £200–£300.

Safety System Codes

E28 Flue Fault Often caused by a frozen condensate pipe in winter. If the pipe isn't frozen, this indicates a more serious flue problem requiring immediate professional attention. Estimated cost: £150–£300.
E110 Safety Thermostat Operated The safety system has activated due to overheating. Try resetting first, but if it recurs, call an engineer immediately.
E128 Flame Failure The boiler cannot detect a flame. Reset first, then call an engineer if the problem persists.

Common Baxi Combi Boiler Problems

Baxi boilers are generally reliable, but like all heating systems, they can have their off days. Beyond error codes, several physical problems commonly affect Baxi combi boilers. Whether you're in a Victorian terrace in Islington or a high-rise in Croydon, here are some of the most common issues we see with Baxi boilers, and what you can do about them.

1. Leaking Boiler? Don't Ignore It

If you spot water pooling around your boiler, it's often down to worn-out internal components, like a tired pump seal or a faulty pressure release valve.

  • Pump seal leaking? That usually means the part is worn and needs replacing.
  • Pressure valve leaking? The system might be over-pressurised.
Top Tip: Turn off the water supply to your boiler immediately and call a gas heating engineer straight away. Don't try to patch it up yourself; you could make it worse.
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2. Losing Pressure

A healthy Baxi boiler should have a pressure reading between 1.0 and 2.0 bar. If the pressure drops below that, your heating and hot water may cut out. Sudden pressure drops often point to a leak in the system. And while a water leak isn't dangerous like a gas leak, it can still damage your property and push up your repair bills.

To repressurise your Baxi boiler:

  1. Make sure the boiler is switched off and cool
  2. Locate the filling loop (usually silver flexible pipes with valves)
  3. Open both valves slowly until the pressure reaches 1.5 bar
  4. Close valves firmly and restart the boiler
Safety Reminder: Smell gas? Leave the house immediately and call the National Gas Emergency Line: 0800 111 999.

3. Frozen Condensate Pipe

If you’re based in outer London, where winter mornings can be especially icy, you will get a frozen condensate pipe as a result. Since this pipe carries wastewater outside, a freeze can block the flow and cause your boiler to shut down completely.

Signs include:

  • E28 error code
  • Gurgling sounds from the boiler
  • Complete system shutdown
Emergency Fix: If safe to do so, you can thaw it gently with warm (not boiling) water over the external pipe and insulate the pipe afterwards to prevent recurrence or call an engineer to handle it properly.

4. Boiler Won't Ignite

If your Baxi boiler refuses to fire up, you might see a fault code on the display. Common ones include:

  • 110 – System Overheating /Gas Supply Problem
  • E131 – Flue Overheat
  • 160 – Fan Issue/ Blocked burner
  • E168 – PCB (circuit board) fault

It could also be something simpler, like a faulty gas valve or ignition electrode.

Avoid DIY attempts. Try resetting first. If ignition failure persists, professional diagnosis is essential.

5. Noisy Boiler? Could Be the Burner

Hear banging or clanking? That's often the sound of a burner on its way out, especially in older Baxi models.

Why it matters: Left unchecked, this could damage your heat exchanger or PCB, resulting in significant repair costs.

6. Cold Water, Hot Radiators

If your radiators heat up but taps run cold, you likely have a faulty diverter valve. This valve directs hot water either to radiators or taps. When it fails, the heating continues to work, but the hot water stops.

Signs of a faulty diverter valve:

  • Hot radiators but no hot water
  • Boiler shows error codes.
  • System corrosion over time
This is a part that needs replacing by an engineer, not a DIY fix.

Diverter valve replacement requires professional expertise and costs approximately £150-£250, including labour.

7. Heating Not Working, But You've Got Hot Water?

The flip side of the problem above, if your radiators are cold but you're still getting hot water, it's likely:

Check the pressure gauge; if it's below 1.0, your boiler needs to be repressurised. If that doesn't work, call in an expert to replace the valve.

When Professional Boiler Repair Help Is Essential

While some Baxi boiler problems have simple solutions, others require immediate professional attention:

Call an engineer immediately for:
  • Gas smells (potential leak)
  • Persistent error codes after resetting
  • Water leaks
  • Strange noises or vibrations
  • Complete system failures
  • Annual boiler service requirements
Can wait until normal hours:
  • Low-pressure issues you can't resolve
  • Intermittent fault codes
  • Reduced heating efficiency
  • Minor operational queries

How to Prevent Baxi Boiler Problems?

Regular maintenance prevents the most common issues:

  • Annual servicing by Gas Safe registered engineers
  • Monthly pressure checks during heating season
  • Bleeding radiators annually to remove air
  • Condensate pipe insulation before winter
  • System flushing every 5-6 years to remove sludge
Get lightning fast quotes. Alternatively, we do offer site surveys where needed.

Professional Baxi Boiler Repair Services

When DIY solutions aren't enough, Serviceteam's gas heating engineers provide expert Baxi boiler repairs across London. Our experienced technicians handle all Baxi models and can quickly diagnose complex faults.

We offer:

  • Same-day emergency repairs
  • Transparent fixed pricing
  • 12-month warranties
  • Annual Boiler service
  • Boiler replacement quotations

Don't let Baxi boiler problems disrupt your comfort. Our team understands these systems inside out and can restore your heating and hot water efficiently.

Getting Your Baxi Boiler Back on Track

Baxi boiler problems range from simple pressure issues to complex component failures. Start with basic troubleshooting - checking pressure, resetting the system, and reviewing boiler error codes. Many problems are resolved with these simple steps.

Need expert help with your Baxi boiler problems? Contact Serviceteam's qualified engineers for fast, professional repairs you can trust.

In the meantime, why not check out our blog on 'Baxi Combi Boiler Reviews' to see how it stacks up in real homes?