Hive thermostat with hand

5 DIY Boiler Repair Tips to Help You Fix Your Own Boiler for Free

Here are 5 DIY boiler repair tips to help you try to fix your own boiler before having to call in a boiler repair engineer.

These are some of the most common simple boiler repairs I come across and that most people can do. Safe DIY boiler repair tips anyone can do.

These are totally safe repairs and do not require you to go inside your boiler, which you should not do if you’re not qualified or competent.

Low System Pressure

Low pressure in your heating system is a simple DIY boiler repair that’s often needed. You will need to repressurise the boiler.

If you have a gravity fed heating system, with a small header tank in the loft, then it won’t be a pressure problem you have as it’s not a pressurised system.

Find the Pressure Gauge

boiler repair pressure gauge

First, you will need to find the pressure gauge on your boiler, or it could be on the expansion vessel if you don’t have a combi boiler. 

The expansion vessel is normally located in the same cupboard as the hot water cylinder tank.

Once you have found the pressure gauge, you need to make sure it’s at between 1 and 1.5 bar.

Top That Pressure Up!

If it’s on less than one bar, you need to top the pressure up using the filling loop and then reset your boiler.

The filling loop will either be on the bottom of the boiler, the pipework underneath, or it could be in the hot water cylinder cupboard.

It is normally two black handles that you need to open, then close them both when you’ve reached the correct pressure on the gauge.

There might only be one handle, and they can be different colours, especially on newer boilers.

Topping the pressure up is one of the boiler repair tips that everyone should know.

Learning how to do it can save lots of money and time dealing with boiler repair engineers.

The Local Gas Engineer Might be Needed.

If your boiler keeps losing pressure regularly, then you most likely have a leak, an expansion vessel problem, or a pressure relief valve problem.

You should probably get it looked at and repaired off a Gas Safe registered engineer if this is the case.

Power Supply

If you are not getting any sign of life at your boiler, like no lights or screen working, then you should check you that are getting electrical power to the boiler.

boiler switched spur
Switched Spur

First place to check is the switched spur, which should be next to your boiler.

A quick fix could be as easy as flicking the switch back on as these can get knocked off accidentally. 

If all is good there, then you can check the electrical consumer unit, or fuse board, to make sure that hasn’t tripped your heating circuit.

It could also be the 3 amp fuse in the switched spur has blown, which can be replaced easily.

Check Your Thermostat

Is It Turned Up?

Room thermostats turn the boiler off when the room that the thermostat is in has reached the temperature you have it set at.

If the room temperature is 14 degrees and the thermostat is set to 13 degrees, then the boiler won’t come on.

Room Thermostat
Room Thermostat

Yes, this does happen…

So make sure it’s turned up!

This could save you from paying the boiler repairer a call-out fee for doing next to nothing, and also save you from looking silly.

Are the Thermostat Batteries Dead?

Wireless thermostats and programmers are powered by batteries, so you should always check them when you’re having boiler problems.

I have been called out to boiler breakdown repairs where the customer did not realise their thermostat was wireless and therefore didn’t know it needed batteries.

Some thinking they need a thermostat replacement.

This is a simple boiler repair tip for most people.

Hive Smart Thermostat
Hive Thermostat

Just open it up and replace with the same type of batteries, normally AA or AAA batteries.

Smart thermostats, like Hive, will email you when your batteries are running out, so you won’t need to worry about them running out fully if you have a smart thermostat.

Bleeding Radiators

Bleeding the air out of each radiator is a very important DIY boiler repair you should learn. Bleeding radiators is simple, all you need is a radiator bleed key.

You could have an airlock in your heating system which is causing your boiler to not work. Or, the boiler might be working, but the radiators are not getting hot because there isn’t any water in them.

brass radiator bleed key
Radiator Bleed Key

You should check all of your radiators for air by bleeding them at the bleed valve with a radiator bleed key. The bleed valve is normally at the top of the radiator on the right, but it could be on the left, or even on the back of the radiator panel.

You may also need to bleed the air from the vent in the hot water cylinder cupboard if you don’t have a combi boiler, you will probably need some pliers to do this.

If you bleed any air out, that means you’re releasing pressure from your heating system, so you will need to keep topping the pressure back up at the filling loop.

Always use a rag to catch the (possibly black sludgy) water when you are bleeding radiators, as you will need to keep bleeding the air out until water starts coming out.

Is The Gas On?

Check the Emergency Control Valve (ECV)

The ECV is the handle on the steel pipe next to the gas meter. Gas meters are sometimes located in cupboards under stairs and kitchen cupboards.

gas meter ecv
Gas Meter and ECV

They can (and do) get knocked off accidentally with coats, bags etc. Check this is turned on. The handle should be inline with the pipe when it’s turned on.

There should also be some yellow tape telling you which way is on and off. Make sure it’s turned on.

Prepayment Gas Meters

If you have a pay-as-you-go gas meter card or key to put money, make sure you have money on it.

Also, if you let them run out of money completely, it can sometimes be quite tricky to get the gas through again. So, you may need to call your gas supplier to get this sorted.


I hope these DIY boiler repair tips can help you in some way. Most of these checks will be included on a boiler service, but they are simple things you check for yourself.

You might have to bite the bullet and ring a local boiler repair engineer if you can’t fix your problem.

Feel free to ask any questions in the comments below about boiler repair tips, and I’ll try my best to help.

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