Gas Boiler Not Working? Checklist to Consider Before Calling The Pros

By: John Garcia | Date Posted: November 24, 2022

If you’re like most people out there, then it’s very likely you own a boiler. Either in your home, your basement, or your garage, and it’s also likely that your boiler has successfully heated your water for decades. If so, then it’s not out of place for it to need maintenance.

However, most homeowners with a broken, inefficient, or leaking boiler tend to encounter a big dilemma – the uncertainty of either calling a professional to fix the problem or getting it done by themselves. Most people seek professional gas boiler repair in London which is understandable – not having hot water or heating is an issue people would like to resolve as soon as possible.

Do you have a boiler that is not working perfectly the way it should? The first thing to do is not to rush into a call for an expert, especially if the fault is minimal. The reason is that you or just any other person can get the problem fixed. So think about it, why spend more?

To guide you, this article has detailed a checklist of some Simple Do-It-Yourself checks and troubleshooting for faulty boilers. Most times, this is what a faulty boiler needs, not the service of a professional.

Simple Do-It-Yourself Troubleshooting Checklist for Boilers

Check your Gas supply.

Sometimes, the fault may not be on the boiler directly but on other equipment like your gas supply. Hence, you need to be sure that other appliances are working.

Also, check the emergency control valve. Is it open? If none of your Gas supply appliances are working, then call your gas supplier because the problem may likely be from the mains.

Check your Boiler’s Reset Button

Another checklist to consider is to check the buttons of the boiler, especially the reset button. Normally, a safety measure programmed on your boiler could have caused the reset button boiler to trip.

You can locate this button on the boiler’s front. But if you don’t find it there, check the manufacturer’s directions (manual). You should NOT have to remove the panel or other core component of your boiler to locate the reset button.

Check your Power Source

Check and ensure that no fuse in your fuse box has tripped. Sometimes it’s easy to overlook the obvious! However, a quick reset will resolve this.

Check whether your boiler pilot light is On.

Check whether your boiler pilot light is On

For old model boilers that have a pilot light, you may need to reignite (restart) it to get it operational. Follow your boiler’s manual for headway.

If it’s a more recent model, try deactivating the burner’s blockage with the deblocking button (Again, your boiler’s manual will help).

Take Heating controls into account.

Take Heating controls into account

Your boiler’s control needs to be checked, and that is the thermostat/programmer. Check whether you need to buy new batteries.

Usually, as your thermostat ages, it will become less accurate, necessitating replacement. Hence, you will need to verify its timer. Take a look at the handbook and confirm that they are configured properly.

Check for Strange Noises

Though boiler noises may seem typical, they can occasionally be inconvenient. The reason is that they play a part in the efficiency of the heat exchanger in your boiler, hence the noises need to be checked and eliminated as much as possible. Once checked and removed, your boiler will function more effectively.

Important to note also, is that even though the majority of noise problems don’t make a boiler abruptly stop heating, they can pose a serious issue later on that will reduce the boiler’s lifespan and obstruct its high-heating capacity.

Check the water level and Check your Boiler’s Pressure

Check the water level and Check your Boilers Pressure

Check the level of the water in the tank. If you see that it is getting low, supply nothing less than 5 feet of water to your tank. This is something you can do by turning on the tap or the supply of the tank.

Additionally, check the pressure in your boiler. To do this, turn on your water heater (if it’s a gas heater). Then raise the thermostat until your boiler’s pressure indicator reads 20 psi. Your boiler is not operating properly if the gauge does not read 20 psi.

Also, boilers must have their pressure checked frequently since low system pressure can cause them to operate less efficiently or even stop altogether. This happens especially in combi-boilers.

If your boiler’s system is working well, the pressure gauge ought to be at 1 bar. To learn how to repressurize a boiler, go online for instructional videos.

Check the Warranty on your Boiler

Before you rush to hire the services of a professional to repair or maintain your boilers, take a few minutes to read through the fine print on your insurance documents. If you do, you may discover that your boiler’s warranty is still active and valid. However, you must submit a claim before work can be kick-started on your boiler.

Check the Condensate pipe of your boiler for frozen conditions

Another checklist to consider is the state of your boiler’s condensate pipe. Check for the error codes or warning lights from the condensate pipe.

It may look a little too complicated for you. If it does, instructional DIY videos can help or wait for professionals.

Radiator controls

Also, check for the control of your boiler’s radiator as it can affect the functionality of boilers. For the radiator controls, try tinkering with them to see if you can warm them up.

However, to alter the setting on a normal lockshield valve, you’ll need to remove the plastic cover and use the proper tool (which can be purchased from a DIY store). When you are done, simply turn the thermostatic valve to the desired setting.

Final Note

A boiler is an essential component in the home responsible for heating water, and similar to other system components in the house, they can also develop faults and stop working anytime.

But instead of rushing to call and hire the service of a professional to check and fix your faulty boiler, this article gives you helpful simple do-it-yourself checks anyone can run for a boiler.

However, if after trying all of the troubleshooting checklists and still your boiler is not working, then, you’re left with no other option than to call an expert. One of the best companies that provide heating repair services in London is – Gas Boiler & Heating Repair LTD is a family-owned company, you can call them 24/7 with any heating issues you may have in South London and Kent by just calling +44 7795 034003. Their address is 49 Pendragon Rd, Bromley BR1 5JZ, United Kingdom, which makes it easy for them to respond to any call quickly and promptly.


  1. How Often Should I Replace My Boiler?

As long as you are taking proper care and maintenance of your boiler, it can last up to 10-15 years or even longer. The decision to replace your boiler, however, should be based on whether the boiler gets faulty consistently.

  1. How Often Should Boilers Be Serviced?

At least once a year. This will help to prolong the working life of the boiler.

Thank you for reading!


John is the founder and chief editor of Homienjoy. With over 15 years of experience in the home improvement industry, John is passionate about helping homeowners confidently tackle their projects. Holding a civil engineering degree and working as a contractor, project manager, and consultant, John brings a wealth of knowledge and expertise to the Homienjoy community.

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