Boiler Not Working? Steps to Take in an Emergency

When your boiler stops working, it can feel hard. You may feel worry, have trouble, and face costs that you did not plan for. To lose heating and hot water, especially in cold weather, is not easy. Families do not want that.

The first step you should take is to do some basic checks before you call a registered engineer. If you look into these things first, you could save both time and money. You will feel better and more in control during the cold weather. Some simple actions may help you get hot water and warmth back faster.

Boilers are gas appliances that help keep your home feel safe and warm. It is not good to take off the cover or try to handle boiler repairs inside by yourself. But, you can look at the front of your boiler and check around the system to spot simple problems. Sometimes, you find the problem to be a power cut, low water pressure, a frozen condensate pipe, wrong thermostat settings, or tripped consumer unit switches. If the boiler issue stays after you check these things, a qualified engineer can get started and fix it for you fast.

Before you do anything: quick safety triage (60–90 seconds)

• Smell gas or think there may be a gas leak? Turn off the gas supply at the meter right away. Open some windows to let the air out. Do not use any switches. Call the emergency number. Do not try to light the pilot light or press the reset button.
• Power out? Check if other lights or sockets near you work. A power cut in your area or a tripped switch in your consumer unit will stop your boiler working, even if you see no problems with other things.
• Prepayment meter users: Make sure you have enough money for both gas and electricity. A card or key with no power is one of the most common boiler problems.
• Water supply present? Turn on a cold tap. If no water comes out, your boiler might lock out and you may get low water pressure warnings.
• Ventilation and flue: Make sure the vents are open, and check the end of the flue is not blocked by ice or other bits during cold weather.

Quick wins most households can try (5–10 minutes)

1. Check the pressure gauge
   The pressure gauge on most combi boilers should read about 1.0 to 1.5 bar when the water is cold. If you look and the needle is low, check your boiler manual or the manufacturer’s guide. These can help you see how to top up the pressure by using the filling loop. If you do this but the boiler pressure drops quickly again, you may have a leak or there could be something wrong with the expansion vessel. A heating engineer or a registered engineer should look at this for you.
2. Verify thermostat and time settings
   A power cut can mess up the time settings on your boiler or your thermostat. Try turning up the temperature, look at any schedules that are set, and change the batteries if you have a wireless unit. A lot of people say they get “no heat” problems just because of wrong thermostat settings.
3. Look for error code / error message
   Many new gas boilers will show an error code or an error message right on the boiler control panel. Write down the error code you see and look out for any flashing lights too. This will help the heating engineer or the registered engineer to know what is wrong. It could be an ignition lockout, or even a frozen part.

What this guide covers (and how to use it fast)

• Common causes of boiler breakdowns and what to check.
  There are many common causes that can make your gas boiler stop working, such as low water pressure or a clogged condensate pipe. You can do a few simple checks on your own for these problems. Look at the pressure gauge, see if there is water, and check the outside pipe for any blocks. These steps help you find some common causes fast and get your central heating or hot water running again.
• Immediate safety steps to protect your home.
  If you think there is a gas leak or if you feel something is wrong with how your boiler burns gas, stop what you are doing. Open the windows to let in some air, leave the area, and call for help right away. These steps can help you and your family stay safe. Always take a gas leak seriously—do not wait.
• How to carry out basic troubleshooting using your boiler manual.
  Open your boiler manual if something is not right. Find the error codes that show on the front. Press the reset button if you have to. You should also check the pressure gauge and set the thermostat if you feel cold. These basic steps work for both central heating and hot water problems. A boiler manual explains these steps in detail.
• The cost of boiler repairs in 2025 without cover.
  It helps to know the normal call-out price and the cost for parts for your gas boiler. This

Who this is for (and what type of boiler you have)

• If you stay in a house that has a combi boiler and don’t use a separate cylinder, you should first look at the boiler pressure, the thermostat, and any error codes.
• If there is a system or conventional setup in the home with a hot water cylinder or with tanks in the loft, you need to check the cylinder immersion, the motorised valves, and the programmer, too.
• If you have a heat pump at home, the checks for control are about the same. But if the issue is with the compressor or with any sensors, you will need a qualified engineer to handle it.

Things you should not do

• Don’t open the boiler case or touch what’s inside, since this is about gas safety.
• Don’t pour boiling water on a frozen condensate pipe. It’s better to use warm water for this problem.
• Don’t keep pressing reset on a boiler if it locks up right away. If this happens, you might have a more complex issue.
• Don’t block the vents or flues. A boiler needs air to burn and work safely.
• Don’t try to relight the pilot light if you smell gas.

Information to gather before you call

Having these things with you helps you check what is wrong faster and saves money at the same time.

• Tell what the boiler brand is, plus the model. Let people know the age. Say the types of boilers that you have. Is it combi, system, or a regular one?
• Share the real error code or error message that you can read on it.
• Look right at the pressure gauge and tell what the boiler pressure shows.
• Say what you already tried. Did you use the reset button, try to add more pressure, or sort out the condensate pipe if it got frozen?
• Tell if someone worked on the heating system lately. Was there a brand new thermostat, did anyone bleed a radiator, or did any electric work happen?
• If you want to compare boiler cover, let people know if it is under warranty or has a cover. Don’t forget to check if the boiler brand or age has rules about getting cover.

A quick call with this info can help the heating engineer know what they need to bring. This means you may not have to wait as long, and it can also lower the work hours you need to pay for.

What are the most common reasons a boiler stops working?

The most common reasons a boiler stops working include low pressure, a frozen condensate pipe, faulty thermostat settings, ignition or pilot light issues, and electrical faults such as a tripped consumer unit. Some problems can be fixed with basic checks, but others require a Gas Safe registered engineer.

The four systems that must all work together

1. Fuel & combustion (gas valve, ignition, pilot light, flame sensing, flue, condensate pipe).

• The gas valve, ignition, pilot light, flame sensing, flue, and condensate pipe all play their part with fuel and burning. You will find that the gas valve and ignition help start the flame. The pilot light and flame sensing make sure the fire stays on. The flue and condensate pipe get rid of fumes.

2. Water circulation & pressure (pump, expansion vessel, pressure gauge, pipework, radiators).

• The pump, expansion vessel, pressure gauge, pipework, and radiators move water in the system. They keep the pressure as it should be. These all work together to make your rooms feel warm.

3. Controls & safety (boiler control panel, thermostats, programmers, sensors, overheat stats).

• The boiler control panel, thermostats, programmers, sensors, and overheat stats let you set the heat. They let you pick when to turn the heating on and off. These parts also help to keep you safe.

4. Electrics & power supply (mains supply, consumer unit, fuses, circuit board/PCB).

• The mains power, consumer unit, fuses, and circuit board give the boiler its power supply. These move the electricity to the right parts. They help it keep working without trouble.

If any of these things are not right, the boiler may not start. It can also turn off on its own to keep itself safe.

Common causes, symptoms, and safe checks

Seasonal patterns (why winter finds weak points)

• Freezing temperatures: The condensate lines can freeze when it is very cold. The outside sensors might stop working if they go out of their range.
• Autumn restarts: After summer, air often gets stuck in the radiators. Valves might stick, and the system could be left with low pressure.
• Storms/power blips: A storm or quick power drop can make the RCDs trip. This messes up the heating schedules and people call in to say their heating will not start.

By boiler type: what fails most often

• Combi boiler (in most UK homes): You might get things like low boiler pressure. A frozen condensate pipe can be one issue. Sometimes, it does not start as it should. If the diverter valve wears out, your hot water can turn into cold water during a shower.
• System boiler (with a hot water cylinder): You can have expansion vessel pressure trouble. A motorised valve can be an issue. A faulty cylinder stat also happens now and then.
• Conventional/regular: The pilot light can go out. Your pump or timer might stop working if the control gear gets old.
• Heat pump: A control sensor may not work well. It can have issues during the defrost cycle. There might be an electrical problem. In this case, call a qualified engineer to look at it.

Early warning signs you shouldn’t ignore

• A new error message sometimes shows up on the boiler control panel.
• You can hear “kettling” sounds from the heat exchanger. The boiler might lock out again and again, or you may need to hit the reset button a lot.
• The pressure in the boiler keeps dropping every week. Take a look and see if there are any small leaks.
• The hot water starts out hot, but then turns into cold water all of a sudden. This could be a problem with the diverter or a sensor.
• Even if you put the thermostat settings up high, the radiators feel only kind of warm. This may mean there is a problem with how the water is moving or with the controls.

Costs at a glance (typical 2025 UK ranges)

• A visit to check for problems will cost you £50–£100.
• A quick fix to a small sensor or the thermostat is often £80–£150.
• A pump that needs to be replaced with a new one is £200–£300.
• A fan or the circuit board will be £250–£400.
• A heat exchanger usually costs £450–£600.
• The new boiler cost, for supply and fitting, is £2,000–£4,500. This does go up or down depending on the size and brand of the new boiler you choose.

If your boiler is out of warranty and getting old, you should look at pay-as-you-go repairs and a cover plan. A lot of people get boiler cover. This can help to lower what they may have to pay if a big part stops working. If you choose to buy a new one, compare energy prices too. A more efficient boiler helps lower costs, but the plan you pick for your energy can change what you pay even more.

Useful vocabulary (so you and your engineer speak the same language)

• Pressure gauge: the dial shows the pressure in the system.
• Expansion vessel: it keeps the pressure steady when water gets hot.
• Condensate pipe: this pipe drains off acidic water. It can freeze in cold weather.
• Diverter valve (combi): this part makes heat go to the taps or the central heating.
• PCB/Control board: it is the “brain” of the boiler.
• Heat exchanger: it moves heat from the flame to the water.
• Programmer/Stat: here you set your time settings and pick the temperature you want.

Most Common Boiler Problems and Causes

These common boiler issues are the reason for almost 80% of all emergency callouts in the UK (Gas Safe Register 2024).

First Step: Stay Safe and Check Power Supply

When your boiler stops working, you need to think about safety first. A boiler has gas, water, and electricity in it. If you rush and press the reset button or try to light the pilot light without doing some basic checks, it may not be safe for you or other people. It is smart to do some basic checks before you fix the boiler or call a heating engineer for help. Always use these steps, so you stay safe.

Gas Safety

Gas is good to use when all appliances are looked after well. If there is a leak or a problem, it can be very dangerous.

• Smell gas? This is the biggest warning sign you can get. If there is even a small smell that you notice when around gas, or if you hear a hissing sound close to your gas supply, turn it off right away at the meter.
• Do not attempt DIY fixes. Do not try to light the pilot light. Do not touch the boiler control panel. Do not reset any part of the system when you think there might be a leak.
• Call the experts. You should call the National Gas Emergency Service on 0800 111 999. A qualified engineer will come to your property so it can be made safe again.
• Ventilation is crucial. It is important to open some windows and doors. This will let in fresh air. Do not switch on any electrical appliance, like a light, because it may make sparks.
• Check other gas appliances. Try to use your gas hob or fire for a short time if you feel safe to do so. If none of the gas appliances work, then the problem might be your gas supplier and not the boiler itself.

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Electrical Checks

Your boiler needs a steady power supply to work. This is true even if it is a gas model. A sudden power cut or a switch that gets flipped can cause the boiler to stop working. This is one common reason why the boiler might not turn on.

• Consumer unit: Go to your fuse box and look to see if any switches are off. A power cut or a problem with something else in your house could make the RCD turn off and this will stop power to your boiler.
• Reset the fuse: Turn the fuse back on. Wait for about one minute. If your boiler works after you do this, the fuse was the thing stopping it.
• Is it just the boiler? Look and see if your lights and other things work. If only the boiler is not working, the real problem might be in the circuit board or you may have a blown fuse in the boiler. A registered engineer will need to check and fix this.
• Display lights and error codes: A blank boiler control panel means there is no power at all. If you notice flashing lights or an error message on the control panel, there is an issue inside the boiler.
• External controls: Look at the programmer or smart thermostat. If the batteries are out or if the time settings have changed after a power cut, then your boiler does not get the signal to turn on.

Tip: Quick power test

Plug a lamp or a phone charger into the same socket as your boiler. If it does not work, the problem is with your power supply, not the boiler.

Water Supply

Your boiler needs to have a steady water supply to work as it should. If the water supply gets cut off or if you have low water pressure, your boiler will not work.

• Test a tap: Turn on the cold tap in your kitchen or bathroom. If you do not have cold water, the main supply may be off. You can check with your water supplier to see if they are doing any work in the area.
• Low pressure: When water comes out but the pressure gauge on your boiler shows low boiler pressure, there may be a leak or a problem with the expansion vessel. A low pressure can make an error code show up. This could make your boiler stop working.
• Hot water cylinder users: If you use a system or regular boiler, you should check your immersion heaters and cylinder thermostats as well. A hot water cylinder may still give you heat if the boiler is not working.

Prepayment Meter Users

If you use a prepayment meter, check your balance first before you feel worried.

• Out of credit = no boiler. If you run out of gas or electricity credit on your prepayment meter, the boiler will stop right away. You will not get hot water or heat after that.
• Top up and reset. When you add more credit, you might have to use the reset button on your boiler or on the meter. This makes the hot water and heating work again.
• Faulty meters. At times, the prepayment meter or card does not work as it should, and this keeps gas or electricity from reaching your home. If topping up and using the reset button does not work, get help from your supplier.

Why These Checks Matter

Taking these early steps gives you three big benefits:

1. Safety: You do not play with gas leaks, bad wires, or trouble in the water system.
2. Speed: When there is a power cut, a frozen condensate pipe, or no credit on your meter, you can sort it out in a few minutes.
3. Saving money: If you call a heating engineer, you can tell them things like, “Power supply is fine, water is coming, pressure is okay, but I see error code E133.” This helps you spend less time and money to get it fixed.

Basic Checks Before Calling a Heating Engineer

You can do some basic checks yourself with no risk.

Reset Button

• Press the reset button on the boiler.
• Wait for about 2 or 3 minutes. See if it starts working again.

Boiler Pressure

• Look at the pressure gauge. It needs to be between 1.0 and 1.5 bar.
• If it is too low, use the manufacturer’s guide to add more pressure.

Thermostat Settings

• After a power cut, make sure that the time settings are right.
• Turn up the temperature and see if the heating will start.

Error Codes and Messages

• Most new boilers will give you boiler error codes.
• Make sure to write these down so your heating engineer can see them.

Condensate Pipe

• If it is winter, the condensate pipe might be frozen.
• Pour warm water on it and then reset the boiler.

If these basic checks do not help fix the problem, then it is time to call a professional.

When to Call a Heating Engineer

A Gas Safe registered engineer should be the person to work on gas boilers. You should not try to fix the heat exchanger, circuit board, or expansion vessel if you do not have the right training. A registered engineer is there to do these jobs. You will be safe if you let them handle it.

Typical Call-Out Fees in 2025

Temporary Heating and Hot Water Solutions

A broken boiler doesn’t mean you have to be cold.

Heating Alternatives

• Portable oil-filled radiators – these usually cost about 30p to 40p for every hour you use them.
• Fan heaters – they warm up a room fast, but they can be expensive to run.
• Gas fire (if safe) – this might be a good backup if it is working well and safe to use.

Hot Water Workarounds

• Boil kettles to get warm water that you can use for washing.
• Use electric showers if they are not hooked up to the boiler.
• Turn on the immersion heater in the hot water cylinder.

Cost of Boiler Repairs Without Cover in 2025

If you do not have cover, you will need to pay for all the repair costs on your own.

This is why a lot of families think that having boiler cover is the best way to feel safe for a long time. When they compare boiler cover, they want to find the one that keeps them and their homes safe. This can help give peace of mind. It also makes sure they feel good about what is ahead.

Should You Buy Boiler Cover After a Breakdown?

After spending a lot of money on one service call, many people start to ask if going for a plan would be better. They want to know if having a plan can help them save money and feel more at ease. A plan may feel like a good idea, because it gives them coverage for more things over time. Many people like to feel sure they’re taken care of the whole year, not just for one problem. This makes them look into what’s the best way to use their money and feel safe with their choice.

• Boiler cover prices are usually from £8 to £20 each month.
• Some plans give you a yearly service. These may also cover gas appliances.
• Plans with no excess could be higher at first, but you may save money later.

👉 You need to always look at and compare boiler cover policies. This will help you get the best cost and the right cover for your needs.

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How Energy Prices Impact Boiler Costs

Even when the boiler works, the energy bills can still be high. This means you may pay a lot for heat even if the system is fine. Many people find that their bills go up at this time, and they want to know what they can do to bring the cost down.

• Old boilers use more gas and this will make your bills go up.
• A new A-rated combi boiler or heat pump can help you save about £300 to £400 every year, says the Energy Saving Trust.
• If you get your boiler checked and serviced on a regular basis, it will keep working well.

Why Comparing Energy Prices Matters for Home Heating

While fixing or servicing your boiler is important for keeping your home warm, the cost of running it is just as critical. Energy prices can make a huge difference to your monthly bills, especially in the colder months. That’s why it pays to regularly compare energy prices — switching to a cheaper or fixed deal can reduce the long-term cost of your heating and hot water.

👉 You can use our tools to compare energy prices. A lot of people save more money when they change their supplier, instead of just getting a new boiler.

Types of Boilers and Common Issues

When a Broken Boiler Means a New Boiler

Sometimes repairs aren’t worth it.

• Boilers that are over 15 years old can often have more big problems.
• If the cost to repair your boiler is more than £600, it may be better to get a new boiler.
• A new boiler can cost you from £2,000 to £4,500. The price can change based on its size and the brand you choose.

Government programs can lower the new boiler cost if you pick something better for the environment. If you choose a heat pump instead of a regular boiler, you may pay less. This is because the government is asking people to use cleaner energy. A new boiler or a heat pump can make you use less energy. Over time, this will help you save money.

How Do I Find Out If My Boiler Is Still Under Warranty or Service Cover?

Before you spend money on repairs, see if you already have coverage.

1. Manufacturer’s Warranty

• Most boiler brands will give you cover for about 2 to 10 years.
• You need to have the boiler checked every year by a registered engineer.

2. Boiler Manual & Stickers

• Look at the front of your boiler. There might be some service stickers on it.

3. Contact Boiler Brand

• Give the serial number to check if you still have coverage.

4. Existing Boiler Cover

• Take a look at your home insurance or boiler cover plan. Some of these might help pay when there is a need for repairs.

👉 Even if there is no boiler cover for you now, you can still compare boiler cover. This lets you protect your boiler later if it breaks down.

FAQs About Emergency Boiler Breakdowns