Baxi Boiler Error Code 118: Causes & Fixes

The baxi boiler error code 118 signals low water pressure in your central heating system. This safety measure stops the boiler from running when there is not enough pressure to circulate water properly, which helps prevent damage. Common causes include natural pressure loss, bleeding radiators, small leaks, or issues with the filling loop.

What Does the Baxi Boiler 1180 Error Code Mean?

The baxi boiler 118 error code means the system pressure has dropped too low for safe operation. The boiler needs a certain level of pressure to move hot water around your radiators and taps effectively. When it falls below this, the boiler shuts down to avoid problems like overheating or poor performance. You will usually have no heating or hot water until the pressure is corrected.

What Causes the 118 error code on Your Baxi Boiler?

The 118 error code on your Baxi boiler is most commonly linked to low system pressure, but it can also result from leaks or problems with the pressure sensor. These issues often appear after you bleed radiators or during colder months when the heating runs more. Identifying the cause lets you fix it quickly and safely.

Low System Water Pressure

This is by far the most typical reason. Pressure can drop gradually over time or suddenly after you release air from radiators, leaving the system without enough water flow.

How to Fix

1. Check the pressure gauge on your boiler to see if it reads below 1 bar when the system is cold.
2. Locate the filling loop underneath the boiler and open the valves slowly to add water until the gauge shows between 1 and 1.5 bar.
3. Close the valves firmly and press the reset button on the boiler.
4. Watch the pressure for the next few days and contact a Gas Safe engineer if it drops again, as there could be a hidden leak.

Small Leaks in Pipes or Radiators

Even tiny leaks in pipework, radiator valves, or joints can cause pressure to fall steadily over time, triggering the 118 fault code. Understanding the baxi boiler 117 error explained is crucial for diagnosing issues effectively. This error typically indicates a problem with the ignition sequence or gas supply. It’s essential to inspect the boiler regularly to prevent such errors from occurring. Baxi e28 error code solutions can help identify issues related to pressure and ignition failure. These solutions often involve checking the gas supply line and ensuring that all connections are secure. Regular maintenance can significantly reduce the likelihood of encountering the e28 error code and promote optimal boiler performance.

How to Fix

1. Turn off the boiler at the mains and inspect visible pipes and radiators for damp spots or drips.
2. Tighten any loose valves carefully if you spot them.
3. Top up the pressure using the filling loop as described above.
4. Arrange for a Gas Safe registered engineer to find and repair any hidden leaks properly. Consider a boiler cover plan so any future problems are handled without large bills. At PlusHeat our nationwide plans give you quick engineer call outs and real protection for your heating system.

Faulty Pressure Sensor or Filling Loop

The pressure sensor might give wrong readings, or the filling loop valves could leak or stick, leading to ongoing pressure problems.

How to Fix

1. Ensure the boiler is switched off at the wall for safety.
2. Check that the filling loop valves are fully closed after use.
3. Try resetting the boiler after topping up the pressure.
4. Call a qualified Gas Safe engineer to test the sensor and replace it or the filling loop if needed.

A boiler cover plan can protect your boiler by giving you fast access to expert repairs whenever these issues crop up, saving you from unexpected costs.

How to Prevent the 118 Error Code on Your Baxi Boiler

Staying on top of your system pressure and regular checks can greatly reduce the risk of this fault and keep your home warm and comfortable.

Here are some practical steps to prevent the issue:

1. Check your boiler pressure gauge every month when the system is cold and top it up if needed.
2. Bleed radiators carefully and always recheck pressure afterwards.
3. Get an annual boiler service with a Gas Safe engineer to spot leaks or sensor wear early.

Frequently Asked Questions 

How often should I check the pressure to avoid 118 error code?

Checking once a month is ideal, especially after bleeding radiators or during seasonal changes.

Can I ignore the 118 code if the boiler still produces some heat?

It is not recommended, as running with low pressure can lead to further damage over time.

Is error code 118 the same as E119 on some Baxi models?

Yes, both generally point to low pressure, though display formats can vary slightly by model.

Does adding more water too often cause other problems?

Frequent topping up may indicate a leak, so it is best to have it investigated by a professional.

Will hard water areas make pressure faults more common?

It can contribute indirectly through sludge build up, making regular servicing even more important.