When your boiler does not keep going, it may be a cause of concern. There may not be any heating or hot water, and you will desire a fast and safe solution. This guide presents simple steps that are easy to follow by the majority of people.
It remains oriented towards the usual ignition issues in gas and combi boilers. You will get safety Inspections, quick repairs, what to do in case there is no error code, Worcester and Vaillant brand tips.
The Preparation Before You Start
- Switch Off Electrical Supply
To ensure that you do not touch any wiring or open a panel, you must switch off the boiler at the isolator, and where necessary, at the mains fuse.
- Smell Gas? Evacuate
In case you smell gas, evacuate the area and do not use any switches and phones in the area of leakage and call the gas engineer..
- Small Checks
Small checks are alright with the majority. In case there are tests where shots are required, involve an expert.
Quick Checks You Can Do Now
The problem is often resolved by following checks;
1. Check Display and Error Codes
Search Error Codes or a Lock out Interpretation. Note the code. A blank display provides a hint even when there is no code regarding a power or PCB problem.
Note: In case you are unable to find a code and a display, verify the power and fuse.
2. Check the Power and Timer
Boiler Is On? Ensure that The Boiler Switch is projected and the timer / programmer is energised. Check to see whether yours has a smart thermostat or timer and make sure it is on heat call.
3. Reset the Boiler
Lockout can be cleared by simply pressing a few keys. Press the reset button once, and wait until the boiler tries starting up again. Read our Step-by-Step Guide to Safely Reset Your Boiler in the UK
4. Check Pressure Gauge
Depending on most combi boilers, stability of pressure should be in the range of 1 – 1.5 bar when cold. At low pressure (lower than 0.8 bar), the boiler might not start igniting.
5. Re-Pressurising
Add the filling loop to get the pressure up. Take the instructions of the manufacturer or contact an engineer in case of doubt.
6. Check the thermostat and Room Controls
Thermostat Set Correctly? Ensure that the temperature of the thermostat is higher than the room temperature.
7. TRVs or Zoned Controls
Compare thermostatic radiator valves or zone controls in case only part of the radiators are cold.
Fire-Ignition Trouble and Troubleshooting
The most common situations that lead to a boiler failing to start are listed below in the easiest to most complex order;
Issue: No Power / Dead Display
What Happens: Makes no display, no fans and no pumps.
Steps
- Test the mains switch of the boiler and the fuse of the house.
- Check the internal fuse of the boiler (it is usually 35A), and must be of the same type only.
- In case the mains are operating but there is no display, the PCB can be defective. Call an engineer.
Issue: Pilot light not turning on (Boilers of older age)
What Happens: You have an older boiler that is lit with a visible pilot flame which fails to light.
Steps
- Make sure the gas is turned on.
- Observing the lighting instructions of the manufacturer.
- The pilot will not remain lit, it is possible that there is a problem with a thermo-couple or gas valve, anyway call an engineer.
Issue: Problem with Electronic Ignition (Modern Boilers)
What Happens: The boiler attempts to light on fire but it gets locked out. You will smell gas that has not been burned.
Steps
- Check with error codes and reset.
- Check exterior pipes concerning condensed frozen pipe (see later) in case of cold out.
- When the ignition electrode or ignition lead is faulty, then the combustion will not start – an engineer will test and replace.
Issue: Non-firing Boiler with a power failure.
What Happens: After power is restored Boiler will not restart.
Steps
- Once again reset the boiler to clear lockout.
- In the event that it attempts and fails, examine the fuse and exhibit.
- In case it is not working, it can have an issue with the ignition module or PCB.
Issue: Flue or Air Combustion Blockage.
What Happens: The Boiler starts but the flame is not lit or flame put out.
Steps
- Look outside the terminal to confirm that there are no blockages such as leaves or nests.
- In case you have a condensing boiler you should ensure that the condensate tap is not blocked.
- Flush all obstructions at a safe distance or seek advice from an engineer.
Issue: Frozen Condensate Pipe.
What Occurs: Condensate will freeze in the winter pipe creating a pressure switch lockout. Boilers can indicate an F1 or lock out or even fail to start.
Steps
- Warm (not boil) water or a hot towel should be used to warm the condensate pipe that is exposed.
- Once thawed, reset the boiler.
- There should be a layer of insulation in order to ensure the future freezing of the pipe.
Issue: Reduced Gas Pressure
What Happens: Due to the presence of power, the boiler attempts to initiate ignition but without success.
Steps
- Get neighbours to check whether they have gas, if not, then yours is likely to be isolated.
- Check the gas meter so that it is turned on.
- In case you think there is a problem in the supply of gas, contact the gas supplier. Do not make an attempt to repair gas supply. It can be dangerous.
Issue: Flame Detection Or Flame Sensor Fault.
What Happens: Sparks get in the flame initiated by a boiler, but the sensor fails to observe, and it lock-outs.
Steps
- The sensor can either be contaminated or defective.
- The flame sensor or ionisation probe will either be cleaned by an engineer or replaced.
Problem: Air Pressure Switch / Fan Fault.
What Does it Do: The boiler is turned off before the ignition since the fan or pressure switch is not on.
Steps
- Hear the fan as the boiler tries to kick-off.
- In case there are no sounds of the fans, the fan can be defective or the pressure switches may be clogged.
Pro Tip: Contact an engineer, these components must be tested.
Problem: Electricity Malfunctioning Gas Valve or Ignition Module.
What Happens: Boiler does not start correctly, gas is not flowing.
Steps
- This is the repair specialists’ work. Do not endeavour to strip the gas valve.
- Get a Gas safe-registered engineer.
What to Do In Case of the Absence of an Error Code
The boiler may sometimes fail to display any error and will also fail to start up. Follow these checks:
- Check the power supply, boiler, switch and fuses.
- Check pressure and thermostat: frequently it is these.
- Do not repeatedly reset it can be an indicator of a fault that cannot be resolved.
- Listen and smell a buzz, a click or even a gas that smells is a story.
Note: In case these measures are not effective it is time to call an engineer. In case of older boilers or frequently failed, it is best to read about replacing your boiler at the right time and see what grants are available to assist you.
Model-Specific Advice (Worcester And Vaillant)
Worcester Boiler Not Firing Up
- The Worcester Greenstar boilers are prevalent. In case yours is not firing, check display codes and pressure.
- Worcester manuals typically display the process of resetting and re-pressurising. In case a particular fault in ignition is observed, it could be a fan, PCB or diaphragm fault in the gas valve. Diagnosis will be done by a Gas Safe engineer.
- This is due to the fact that the cold water supply matches both the supply and demand of boiler heat.
Vaillant Boiler Ignition Fault
- Vaillant boilers have certain ignition fault codes. Record the fault code and find instructions.
- The ignition module and the flame sensor of Vaillant can malfunction with time.
- Once power, pressure and reset have been checked, get a registered engineer in case of persistence of code.
Combi Boiler Not Firing Up - Extra Checks
- Combi boilers are dependent on the tap water flow to initiate heating. In case the combi boiler fails to start with the activation of a tap, examine the flow and pressure.
- Combination boilers have blocked filters which may prevent the flow sensor from sensing water.
- Wipe off the filter or get an engineer.
- It is important to note that some types of boilers are ineffective because they are affected by chemical corrosion that damages the heat exchanger.
Electric Boilers and Ignition Problems
- Electric boilers do not have a gas ignition, therefore, not firing up indicates no supply of power to heating elements.
- Check electric supply, fuses and the inverter/PCB.
- In case you doubt electric faults, seek the services of a professional electrician.
- Furthermore, compressing the air supply system or pipe with alternative compressed air results in a vacuum that causes entrapment.When To Call An Engineer
Call an Engineer if
- You smell gas or feel that there is a gas leakage.
- The boiler locks itself out many times over following a reset.
- It has indicators of a damaged gas valve, charred PCB, or ignition module.
- You are not sure that you can perform the checks safely.
Employ an engineer who is registered on the Gas Safe list. In case the boiler is old, read Right Time To Replace Boiler and Boiler Upgrade Tips for First-Time Homeowners.
Troubleshooting (One Page Summary)
- Is the fire to the boiler on and the show on?
- Is there a request to have the heat by the programmer/thermostat?
- Is the pressure 1–1.5 bar (cold)?
- Frozen condensate pipe? Blocked condensate pipe?
- Is the gas supply active?
- Does it have error codes or lockout?
- Have you tried a single reset?
- Was the boiler not making a strange noise then it stopped?
Important: In case the response to the last three is yes, write down information and summon an engineer.
Engine Preventive Ignition Problems
- Annual Boiler Service
Have the boiler serviced once every year. This maintains the ignition parts hygienic. Also check Ensuring Boiler Safety and Efficiency in The UK guide.
- Insulate Pipes Condensing
Only insulate these during the winter.
- Install a Carbon Alarm
It is good to have a carbon monoxide fume alarm around sleeping areas like your bedroom.
- Replacement of Old Boilers
In case the boiler is old or has failed over and over again, refer to either New Boiler Cost or Best Boilers UK.
When Replacement Makes Sense
In case your boiler has ignition failures repeatedly, there is a risk of parts breaking down and safety is at risk. In case you want something green, take a comparison between gas and electric one and Air Source Heat Pump Vs Gas Boiler.
What Home Energy Guide Can Do
Home Energy Guide concentrates on grants, schemes and upgrades that have the potential of reducing your long time costs. You may get schemes of subsidised or free replacement of your boiler as it gets old or cannot be repaired.
Your New Boiler Could Be Free – Check Eligibility!
Frequently Asked Questions (FAQs)
When the boiler does not start to fire, usually another person will find that the pressure is low or the ignition is locked out, the flame sensor failed or there is a blockage of the condensate pipe. Attempt to check pressure, reset and thaw any condensate pipe. In case of the persistence of the issue, invite a Gas Safe engineer.
In the case of combi boilers, the flow of water and pressure should be checked initially. The boiler can be prevented to detect demand by a blocked flow sensor or filter. Also make sure that the cold water is turned on to the combi. Assuming that they are okay, the problem can be that there is a pump or sensor, which needs the attention of a professional.
There is a common mistake code that refers to the problem of power or display. Check Mains supply, boiler switch, internal fuse and pressure. Reset the boiler once. In case there is still no indication of the ignition and the display is clean, it could be that the PCB is defective and you need to call an engineer.
An iced discharge is usually observed at the exterior of the pipe which is frozen in condensate. To repair, place the pipe in some warm water, or a hot towel to warm it up, and reset the boiler. Wrap the pipe in order to avoid future freezing.
In the case of Worcester boilers it will begin with the display, pressure, and reset. Look at similar lock out codes. When such a step cannot work, it is probably an internal cause of the problem that refers to the fan, gas valve or PCB and you have to call a Gas Safe engineer.
Basic check-ins (power, pressure, reset) are secure. Do not strive to modify gas valves, ignition modules and internal gas parts. In case of smelling the gas or in lack of confidence evacuate and call on the certified engineer.
Possibly. Home Energy Guide assists with free boiler grants as well as the upgrade schemes to those who meet the criteria. Check your eligibility now!
If there is a power outage, you have to restart the boiler after checking the fuse and screen once after the outage. In case the boiler attempts and shuts off, the ignition module or PCB might be broken. Call a Gas safe engineer in case a reset is required and can restart normal functioning.
