Baxi 118 Boiler Fault Code

Here, we're going to discuss the 118 fault code on the Baxi boiler. Emergency Boiler Repair..

The Baxi Boiler Fault Code 118 Fault Code Common Q&A

Just below, we have a list of common questions relationing to the 118 fault code on the Baxi boiler.

What does the Baxi 118 fault code mean?
What is the recommended fix for the Baxi 118 error?
Do I need a new boiler if I have a Baxi 118 fault, and if not, how long will it take to fix?
Where can I find the filling loop on my Baxi boiler?
What pressure does a boiler need to be to fix a 118 fault code?
Do I need to turn off the mains water if I have a leak?
How do I find the leak causing the 118 fault code?
The leak is coming from the boiler, is it dangerous?
What is the cause of a leaking boiler?
I don’t have a leak, what else can cause the Baxi 118 error code to be displayed?
How do I know if the pressure gauge is faulty?
Will a dripping condensate pipe cause a 118 fault on a Baxi Boiler?
How much does it cost to fix a Baxi boiler with a 118 fault code?
How long does it take to bix a broken boiler being a 118 Baxi fault code?

What does the Baxi 118 fault code mean?

According the Baxi’s own list of error codes, the 118 fault is directly related to low water pressure in the boiler.

If you have low pressure, there’s a good chance you have a leak in your central heating system.

What is the recommended fix for the Baxi 118 error?

Baxi recommend adding water (and therefore pressure) via the filling loop.

This is a temporary, not permanent fix.

If pressure has dropped once, it will drop again.

You need a plumber to fault find your central heating system, and determine where the leak is coming from.

You can find a plumber here.

They’ll run diagnostics to figure out exactly where the fault is coming from.

On some occasions (i.e. a soldered joint is leaking), a quick fix is all that is needed.

On other occasions (i.e. the pressure release valve has failed), they’ll need to install replacement parts.

Do I need a new boiler if I have a Baxi 118 fault, and if not, how long will it take to fix?

Without running diagnostics, it’s hard to determine the cause, and the solution.

For example, if a pump has blown seals, leaking water onto your PCB (printed circuit board), and your boiler is 10+ years old, you’re better off with a replacement.

The cost of the fix would be horrendously high (well into the hundreds of pounds); it makes no sense to invest that much money into an old boiler.

But, some good news.

Most of the time, a Baxi 118 fault can be fixed in under an hour, and you won’t need a new boiler.

Where can I find the filling loop on my Baxi boiler?

99% of the time, your filling loop is underneath your boiler.

There’s a fill valve you’ll need to use to add pressure.

What pressure does a boiler need to be to fix a 118 fault code?

To know the exact pressure your boiler needs, you’ll need to refer to your owner’s manual.

Most boilers will require a pressure of 1.3 bar to work at their optimum.

Open the valve slowly, you don’t want to add too much pressure to your central heating system.

Do I need to turn off the mains water if I have a leak?

As a rule of thumb, the amount of pressure loss, will match up to the water loss. And, this water needs to go somewhere; hopefully not on your carpet.

But, as pressure drops, less and less water will leak from the central heating system.

Imagine squeezing toothpaste with the same amount of pressure when it’s full, as when it’s nearly empty; what comes out at the end is a lot less.

So, 99% of the time, there’s no need to turn off the mains water.

We’d consider it more of a priority to figure out what is causing the leak, and fixing it as soon as possible.

You can do this by booking an emergency plumber here.

If your pressure is dropping quickly in your boiler and you want to play it safe, you can turn off the water using the mains stopcock.

How do I find the leak causing the 118 fault code?

Most leaks will be visible.

You’ll be able to see drips coming from:

Soldered copper joints.
Radiator valves and towel rail valves.
Connections to the boiler.
The boiler casing.

Here’s the problem; not all leaks are visible.

Leaks could be coming from places that you can’t see such as:

Pipework and soldered joints in partition walls, or wall coving.
A failed pressure release valve.
Blown boiler pump seals.
A faulty auto air vent.
A broken expansion vessel, or an expansion vessel that needs more pressure.

The leak is coming from the boiler, is it dangerous?

Especially on newer boilers, many electrical parts are sealed units.

That’s not to say that having a leak near electrical parts is ideal.

We’d advise switching off the boiler, and calling an emergency plumber to rectify the problem.

What is the cause of a leaking boiler?

We find that on most emergency calls, the boiler pump is at fault.

Sometimes it’s because the pump has worked itself loose, and damaged internal parts.

However, the internal seals are sometimes to blame. Once they blow, water will start leaking from the pump.

Many newer boiler pumps (such as Grundfos) have flow settings (1-3).

Some properties won’t need the maximum flow rate, and in the case of a system that’s full of heating sludge, a high flow rate can increase back pressure, blowing the pump seals.

If the seals aren’t completely shot, reducing the flow rate to the lowest flow setting can stop the leak; temporarily.

I don’t have a leak, what else can cause the Baxi 118 error code to be displayed?

99% of a time if a boiler is losing pressure, there’s a leak in the central heating system.

The only occasion a leak can’t be blamed, is when the pressure gauge on the boiler is faulty.

Please bear in mind, this is not common, even for old boilers.

It’s much more likely that your central heating system has a leak.

How do I know if the pressure gauge is faulty?

Not very easily. It’s a much better idea to have an emergency plumber diagnose the problem.

You can book one here.

If your pressure gauge has dropped to 0-bar, that doesn’t necessarily mean it’s faulty; that’s just as good an indication of a leak, as a faulty pressure gauge.

Will a dripping condensate pipe cause a 118 fault on a Baxi Boiler?

No, As a boiler operates, it produces a small amount of waste gas. This gas turns into water, and is taken outside by the condensate pipe.

Condensate pipes can be a cause of boiler faults, but it’s usually relating to frozen waste water, that causes a boiler lockout (i.e. the boiler will shut down).

How much does it cost to fix a Baxi boiler with a 118 fault code?

No, As

How long does it take to bix a broken boiler being a 118 Baxi fault code?