June 18, 2021

Reasons Why Your Boiler Might Not Be Working

After turning on your central heating, it takes around 15 minutes to notice that there is no heat or hot water. It’s more than simply bad luck on a freezing Monday morning if that happens. There’s something wrong with it. Although your boiler is definitely not starting up for central heating, attempt the following simple checks before calling a boiler repair. If there is no power or gas to the boiler, this seemingly inconvenient issue may require a quick DIY remedy. To avoid problems it’s best to always book your annual boiler service.

However, if the problem is with the boiler burner, fan, or pilot light, you should get it diagnosed and repaired by an expert. As you may be aware, boiler difficulties can result in life-threatening circumstances and carbon monoxide leaks, so act promptly and call a Gas Safe licenced engineer to repair your boiler for you.

This article is perfect if you’re a person who:

  • has moved into a new property but skipped the pre-purchase plumbing and gas check;
  • needs professional help from a trusted tradesman;
  • can’t get any heating or hot water due to boiler lockout;
  • has moved into a new property but skipped the pre-purchase plumbing and gas check;
  • wants professional help from a trusted tradesman;
  • has a boiler that is ancient and unreliable;

In this article, you’ll learn about the most common reasons for your boiler not starting, what the error code on your boiler display means, and how to fix it.


#1 – The boiler is ineffective

To fire your boiler, you’ll need a modest amount of electricity. Keeping that in mind, here are some potential reasons why your boiler isn’t working:

  • When there is heavy snow, lightning, strong winds, or other severe weather conditions, there is a power outage;
  • You’ve made manual adjustments to your thermostat’s settings;
  • You’ve unintentionally shut off your boiler;
  • The breaker tripped because the circuit was overloaded;
  • The temperature in your home has been set to the desired level.


  • Locate the reset button and hold it down for 10 seconds;
  • Allow time for the boiler to ignite, which could take several minutes. If the indicator light is green and the error code has vanished from the display, you’ll know it’s ready.
  • If the fuse box has tripped, turn it back on.
  • Make sure the boiler’s isolation switch is turned on.

#2 – Your home’s gas supply has been disrupted or is insufficient

Boiler ignition will be stymied if the gas supply is interrupted or insufficient. Your gas supply could be limited or non-existent for a variety of reasons.

First and foremost, there may be a problem with the supply to your property, but there is little you can do about it. It’s also possible that your gas metre is frozen, resulting in low gas pressure. Last but not least, your low gas supply issues could be caused by the gas valve, which would ordinarily open to offer more fuel. Because the gas cannot reach the chamber if it is faulty or broken, the boiler will not ignite.


Keep the number of outstanding payments to a bare minimum. Check to see if you have any outstanding invoices.

To prevent your gas metre from freezing, wrap it in insulation. The most effective method is to lag it.

Check to see if the gas supply has been switched off.

Did you replace your old boiler with a high-efficiency combi boiler recently? It’s possible that your gas provider is to blame. It’s possible that the gas supply is outdated and insufficient for the modern high-output combi boilers. The outlet gas pressure can be tested by a Gas Safe/Corgi registered plumber near you. If it’s low, you’ll need to speak with your gas provider directly.


#3 – The boiler timer is broken or the boiler isn’t responding to the thermostat

If you recently had a power outage or the clocks changed, your boiler may have been reset to its factory default settings, causing it to fire at the incorrect time.

Another culprit could be an old thermostat that incorrectly reads the temperature and produces an ignition problem. Your boiler will also not ignite if your thermostat is set too low or if it is too close to a heat source.

Solution: Make sure the boiler’s timing is right

Reset the timer – remember that the timer will reset to midnight once you do this, so make sure you modify it afterwards;

Raise the thermostat to see if the boiler comes on;

If the thermostat is located near a radiator, oven, towel rail, or other heat source, consider moving it.

Check to see if the heat has been turned down by you or someone else.


#4 – Excessive air in radiators

If you’ve observed that the tops of your radiators aren’t heating up as quickly as the bottoms, you’ve likely got air trapped in them. The pipes and radiators circulate hot water, which is how central heating works. Small pockets of air form over time, and because air is lighter than water, it climbs to the top of the radiator, making it inefficient to run. It’s possible that your boiler will stop working as a result of this.


Radiator bleeding, or releasing trapped air, will keep your house warm and cosy while also saving you money. Fortunately, bleeding the radiators is a simple do-it-yourself project.

If you’d prefer have a heating expert handle it for you, schedule a radiator bleeding service right away.


#5 – Boiler pilot light won’t light – flame failure

The pilot light is a little flame within the boiler that ignites the gas and boils the water as a result. There is no hot water and no warmth when it runs out. The most common cause is debris blocking the jet. A draught from a poorly sealed window or a defective thermocouple may be the cause of the light going out on rare instances.

You might be able to see the light through the framework on older boilers, but on modern models, the error code on the display will indicate if there is a problem with the pilot light.

Disclaimer: The light is crisp and blue in typical circumstances. However, if the light is yellow or orange instead of blue, switch off your boiler right away! This is a hint that carbon monoxide, a deadly, odourless gas that is lethal, is being generated.


We recommend that you use a qualified professional to complete the task:

Turn off all gas appliances, all faucets and showers, and the gas valve before lighting the pilot light.

Allow 10 minutes for the gas odours to disperse. As a safety measure, always keep a window open to allow fresh air to enter.

Locate the pilot light jet by removing the cover;

Hold a long candle or a barbecue lighter near to the pilot light tubing.

Make sure the gas valve is set to pilot. You have an automated ignition system if your gas valve only has two settings: on and off.

After the flame has been started, press and hold the reset switch for roughly 30 seconds.


#6: Boiler pressure is too low / high

When the heating is on, the boiler pressure is usually around 1.5-2 bar, and when it is off, it is approximately 1-1.5 bar. Any changes in the water pressure metre on the front of the boiler should be noted. If the pressure is greater than 2, it’s possible that your radiators require bleeding or that the pressure valve has become loose. If you have a boiler that is dropping pressure – less than one – you might have a leak. It’s also possible that it’s the result of recent radiator bleeding.

Disclaimer: Always consult your boiler manual to see what the best temperature range is for your particular unit.


In other words, when:

  • bleed the radiators if the boiler pressure is too high;
  • Repressurize your boiler if the pressure is too low.

#7 – A malfunctioning boiler burner

When gas is burned in a boiler, CO2 is produced, which can clog the burner, leading it to work infrequently or not at all. The burner will also deteriorate with time and may need to be replaced.


The carbon build-up can be cleaned out or the burner replaced by a competent boiler engineer. Having your boiler serviced at least once a year will save you time and money in the long run.

Heating and hot water aren’t working?

Any boiler brand and model can be repaired by a skilled team of Gas Safe Registered specialists, or an outdated and inefficient unit can be replaced with a new A-rated appliance.

Given the variety of repairs and replacement parts that may be required, it’s difficult to estimate how much a repair of a fire-up issue will cost.


There are several key reasons why your boiler will not fire for central heating or hot water, the most prevalent of which are:

  • The electricity supply
  • The supply of natural gas
  • The timer on the boiler
  • In the radiators, there is trapped air.
  • A frozen condensate pipe is a serious hazard.
  • A diverter valve that isn’t working properly
  • The pilot light is on.
  • The stress is mounting.
  • A malfunctioning boiler burner

Some of these difficulties can be resolved on your own, but if you are unsure, it ialways advisable to consult a boiler engineer to protect your family’s and home’s safety. Get a quote from Elite Group today.