January 23, 2020

Boiler Not Working? Top 5 Common Fixes

A complete guide to getting that boiler working again and some common fault codes and how to fix.

Boiler Not Working? Top 5 Common Fixes

What's in this article?

Boiler not working?

See how we can save you money

Why is my boiler not working?

There are a lot of reasons why your boiler may not be working. Some Common fixes include a frozen condenser pipe, no gas to the boiler, pressure being too low, a leak on your existing system, faulty controller and more.

Boilers are complicated pieces of equipment, but many people rely on them to get hot water and proper heating in their home.

Unfortunately, like all complex machines, they can sometimes simply break or stop working, even during the installation process.

Whether it is an issue with the radiators, the water supply or just a misplaced valve or just your boiler is not working, it can be hard to notice your boiler issue until the problem has already started putting pressure on your other appliances.

Unlike a computer a new boiler is not quite as simple as turning it off and back on, however this can sometimes work.

Here are some of the top boiler problems which may avoid you having to buys a new boiler.

Top 5 Broken Boiler Problems

Before having to cash out for a new boiler here are the top broken boiler issues that can plague most modern boilers and possible solutions. Some are minor, but others will require an engineer to be called out to repair it.

Knowing the difference between a DIY boiler repair job and a situation where calling for a full engineer quote is important.

Boiler not working common fixes for old combi

1. Leaking or dripping boiler

A leaking combi boiler is one of the most well-known causes of a boiler not working. A leak can spring up anywhere in the system and drop the boiler pressure significantly - if it's after the boiler pressure gauge, it might not even get picked up by the readings.

Check everything that's exposed, such as radiators, as well as the boiler itself. If you don't see any obvious signs, then you might have to contact an engineer and get them to look at the entire heating and boiler system themselves.

Pressure keeps dropping?

If you find that the pressure on your boiler continues to drop after topping up this may be a sign that there is a leak on your existing system.

These type of leaks can be hard to find as it means following your pipework from the boiler throughout your home to every connected point.

Fix: It's time to call an engineer.

2. No pilot light to the boiler

This can be quite noticeable too since it stops the boiler from actually heating up everything that passes through it. No pilot light or thermostat means that your boiler will produce no central heating or warm water.

Very few new boiler designs use an actual flame anymore, so you'll be relying on technology instead: if you can't restart it, get an engineer to take a look since they're more likely to identify the damaged components correctly.

Fix: If you are on pre-paid meter make sure you have credit. Contact the gas company to ensure you have a live supply. Restart the pilot light, see your boilers manual for more information.

3. Gas problems

These aren't very common these days but can be extremely dangerous. You'll need a Gas Safe Registered engineer to handle these problems since they're certified and qualified to offer engineer services and/or a quote concerning boiler systems that use gas as fuel.

Even something as small as a broken valve can cause a gas leak or a build-up of flammable fuels, so don't attempt to fix it yourself unless you're also a Gas Safe Registered engineer.

Fix: Call the National Gas Emergencies number immediately on 0800 111 999.

4. Controller timer scheduled

If you find your boiler not firing up for the central heating at a scheduled time, there might be something wrong with the scheduling timer: this is mostly a feature of electronic boiler models that have built-in online connections or time settings.

It could be something as small as the clocks changing or the options being set incorrectly, but it can still be irritating to deal with. Try to adjust the settings or refer to the manual if you don't know-how.

Fix: See your thermostat manual on advice on how to setup correctly.

5. Fuel and electricity issues

This is always important since your boiler needs them for even its most basic functions. If you don't have any electricity or gas heating water up, then you need to try and reconnect everything.

This can be incredibly risky if you are untrained, but a professional quote can be higher than expected depending on the problem. We would advise not to do this yourself and call a Gas Safe engineer.

Fix: Call the professionals.

Why would a boiler stop working?

The general purpose of most new boilers is to heat up and transport water to various different appliances. Almost everybody who owns one got their boiler for hot water, so you can usually assume that it is an issue with the supply or pipes in some way.

If even a single pipe or valve is broken, it could lead to the entire boiler system losing water pressure and struggling to keep the flow moving. On the other hand, if it is the heating system that breaks, the water might not be warming up properly at all.

Boiler problems with pilot light

Simply just stopped working?

In general, if your boiler simply "stops working", then there is something wrong with the system that's affecting its ability to actually provide the hot water you need.

A small leak or worn-out heating system can reduce its efficiency or make the boiler pressure drop slightly, but it wouldn't break everything in an instant, which hints at it being a bigger problem.

How do you restart a boiler?

Different boiler models such as combi boilers have their own unique designs and functions, but many modern ones have their own automatic lockout systems that will prevent the system from turning on if there is something wrong.

1. Resetting your boiler

To get it working again, you'll have to reset it, even if the problem has been fixed - with no reset, the boiler won't "know" that it's repaired.

This lockout or shutdown feature can activate for various reasons, a key one being unsafe conditions, such as the wrong type of gas or a sudden spike/dip in electricity.

2. Find the right reset button on your boiler

It's not too difficult to reset your boiler, but it can take a while to find the required buttons.

Almost all modern boiler models, both electric and gas appliances, have a restart button somewhere on their body, either in the main control panel or placed around the back like a last-ditch safety measure.

You'll have to get access to the system yourself, so be prepared to open up the cupboard or panel it's placed behind

3. Check the boiler manual for information

If you can't see a button, you should check your manual or an online guide to help you track it down. Some models have them hidden away to stop users from accidentally resetting the system while they're adjusting different parts, but others will put them in very visible spots.

Be careful when following a manual's instructions, since your boiler may be installed at an angle rather than straight ahead.

If you have a Viessmann 050-W combi boiler you can see the online manual here for more information.

4. Give it a little time..

Once you find it, you should follow the manual again for advice. If you can't find any information, try holding the button for around ten seconds: this is more than enough time for an average boiler to fully restart - then you just need to wait a few minutes for the system to re-ignite.

Avoid pressuring the button again unless you're absolutely sure it hasn't worked since this can break some of the important components inside.

Fixing a broken boiler

How do I know if my boiler is broken?

The easiest way to tell if a boiler has stopped working is to see if there's no hot water. A lack of central heating, radiators that don't provide heat or other obvious signs could hint that something is very wrong with the boiler in terms of its heating system - either the heating itself or the fuel/power that's needed.

If a boiler is still clearly showing that it's using power (this is most obvious on electrical ones, since they may have power gauges or digital displays), it's clear that the problem isn’t a lack of fuel. In these cases, simply restarting the boiler or re-connecting it to the electricity/gas mains won't be enough, since the issue is still in there somewhere.

The pilot light may be out

If you notice your gas boiler not working as it should be, you might have to look at the pilot light or the gas supply and figure out how much fuel is actually getting through.

All gas appliances need a near-constant gas supply to work correctly, and if none of it gets to the pilot light (or the pilot light isn't working), then it can't ignite and ensure that you get the temperature that you need.

These are only surface-level problems, though: there can be some much more serious issues that take a lot longer to fix. For example, if you notice that the boiler pressure gauge has dropped by a significant amount, then a pipe or valve has broken in a way that makes it hard for water to move around properly.

Frozen condensate pipe?

On the other hand, if it's too high, your condensate pipe might be broken or frozen instead, meaning that the water's not able to leave the system properly and is getting backed up.

Both of these can be dangerous if left unchecked, so you need to fix the pressure right away: for low boiler pressure, look for leaks in the pipes (both before and after the water passes through the boiler), and try to fix high-pressure problems by getting the condensate pipe or some key valves replaced.

Fix: You can often fix this yourself. Boil your kettle and top up in a jug with cold water until the temperature it hot but not boiling. Pour this over the condense pipe outside to clear any frozen blockage. Repeat the process if needed.

Preventing your pipes from freezing

Time to get a qualified engineer out

It's not always easy to tell if your entire boiler is broken, but if it is not working and doesn't seem to be turning back on even if you reset it, then there is likely a major issue with the entire system.

At this point, getting an gas safe registered engineer involved or potentially getting a new boiler is key: every second of a boiler not working is a second of wasted fuel, as well as potentially increased damages and repair costs.

Always make sure your engineer is Gas Safe registered, you can check this on the Gas Safe register list https://www.gassaferegister.co.uk

Boiler still broken?

Get a quick fixed price quote

Boiler Error Codes

Some boiler models have error codes to help you identify why they are not working. They can be a shorthand way of identifying many different boiler issues and might even give you some insight into how to fix the current problem.

Always be sure to check your boiler manual if you notice that it's started flashing or displaying digital codes since getting them wrong can be a massive problem in its own way. The boiler codes may vary slightly for new boilers.

Here are some of the most common: make sure you follow them as closely as possible if they apply to your boiler.

Viessmann Boiler Error Codes:

  • 5C/D/E/F = Communication fault with the boiler.
  • D4 = Faulty safety equipment or internal BUS.
  • 0C = No power/flame signal is still running, but boiler is turned off.
  • C1 = Lockout due to voltage fluctuations.
  • F5 = Problems with gas supply.
  • B4 = Major internal fault.
  • B5 = Caused by external safety equipment.
  • 0B = Wind damaging the vent system/water is flowing the wrong way.
  • FE4 = Undervoltage.
  • 0F = Maintenance needed.
  • A3/B0/F1/F-E1/F-E2 = Faulty programming (automatically switches back to factory default settings).
  • B1 = Internal electronics fault.

Alpha Boiler Error Codes:

  • 1 = Complete ignition failure.
  • 25 = Overheated.
  • 37 = Low voltage.
  • 24 = Boiler control panel jammed.
  • 44 = Safety lockout due to various issues.
  • 0E2 = Flame sensor not working.
  • 0E37 = Low boiler pressure.
  • No lights = Electrical fault.
  • Various combinations of flashing yellow and red lights = Severe fault.

Worcester Boiler Error Codes:

  • B7 = Replace boiler control board.
  • D1 = Boiler overheating and/or sensors are overheated.
  • E5 = Primary sensor has overheated.
  • A1 = Boiler contains no water.
  • C1 = Boiler fan has stopped.
  • 260 = Sensors are disconnected, and boiler contains no water.

    Selecting the right gas safe engineer

    How to ensure you select the right gas safe engineer

    Gas Safe Registered

    Always check the Gas Safe register to make sure any engineer that has been asked to work on your home is qualified.

    If you discover the engineer is not registered with Gas Safe then kindly ask them to leave your home, you can also report them to Gas Safe.


    Make sure the engineer understands your request.

    They can advise based on their experience but at the end of the day it it your home, and the job should be completed to your specification.

Get a fixed quote online

Get a fixed online quote today, installation as quick as tomorrow

Check Prices