Consumer Units. What you need to know.

Consumer Units. What you need to know.

by | Aug 24, 2024 | DIY Advice, DIY Electrical Advice, Practical DIY Advice

Consumer Units. What you need to know.

What is a Consumer Unit?

You might hear a Consumer Unit called different things: a Distribution Board, a Fuse Box—whatever. In the trade, it’s mostly called a Consumer Unit, or just CU for short, so let’s stick with that to keep it simple.

I’ll try not to bore you to sleep here, because this stuff matters, but I get it—electrics aren’t exactly thrilling.

No matter what you call it, a CU is what distributes electricity around your home. At its core, a CU should have a Main Switch, which lets you shut everything off if needed. You’ll also find various fuses or MCBs (Miniature Circuit Breakers) that control each circuit in your home.

If you’re lucky (and lots of people are these days), you might also have an RCD. If you’ve got two, great. If each circuit has its own, you’ve hit the jackpot.

Consumer Units come in all sorts of shapes, sizes, and safety levels. We’ll run through some of them below.

Keep reading…

1. Consumer Unit with Ceramic Rewireable Fuses

Consumer Unit with Individual RCBOs

These are old-school and, honestly, look pretty cool (if you’re into that sort of thing). But they belong in a museum, not in your home. If you have one, it’s a good sign that you haven’t had certified electrical work done in ages, so call an electrician.

What it does:

This CU protects against circuit overloads—the fuse wire inside will break if there’s too much demand.

What it doesn’t do:

It won’t protect you from getting shocked or seriously hurt if there’s an earth fault.

What’s an Earth Fault?

It’s when an electrical current tries to escape to the ground (Earth). It is often caused by cutting a cable (e.g. by drilling into it) or a sudden appliance fault.

2. Consumer Unit with Rewireable Fuses

Consumer Unit with Individual RCBOs

These are still fairly common and do the basics.

What it does:

It stops you from overloading circuits by tripping a fuse. You can reset it by pressing a button or flipping a switch—way easier than the older CUs.

What it doesn’t do:

Like the older ones, it won’t protect against electrocution from an earth fault. If you’ve got one, you might need an upgrade if you’re getting electrical work done, since newer regulations prioritise safety and require RCDs.

What is an RCD?

An RCD (Residual Current Device) is a nifty safety gadget that trips when it detects an earth fault. Potentially it will save your life.

At its most basic level, it constantly monitors the current in your house. If it detects an imbalance, it assumes that the current has gone into something it shouldn’t have  – you. It  should trip within milliseconds. This will save your life.

3. Consumer Unit with an RCD as Main Switch

Consumer Unit with Individual RCBOs

This setup has an RCD that acts as the main switch. It’s better than nothing, but if there’s a fault on any circuit, the whole thing shuts down. Not ideal if you’re halfway through cooking dinner.

What it does:

It gives you some protection against earth faults, which is a step up from the older units.

4. Consumer Unit with Two/Dual RCDs

Consumer Unit with Individual RCBOs

For a while, this was the go-to upgrade. These CUs usually have a plastic casing (newer ones are metal for better fire protection) and split your circuits into two groups, each with its own RCD.

What it does:
If one circuit trips an RCD, only half your house goes down. The other RCD keeps things running, which is more convenient but still a bit of a hassle.

You can find these CUs sold cheap in DIY stores because they don’t meet current regulations any more. Don’t be tempted—it’s not a bargain.

And you shouldn’t even be thinking abut carrying out that kind of electrical work anyway. 

5. Consumer Unit with Individual RCBOs

Consumer Unit with Individual RCBOs

This is what electricians install nowadays to meet the latest safety standards.

What it does:

This setup has a metal casing and a Main Switch, with each circuit controlled by its own RCBO (a combined fuse and RCD). If a fault occurs, only the affected circuit is shut down, so the rest of your home stays powered. It also likely includes a Surge Protection Device (SPD) to shield sensitive electronics like TVs and computers.

It’s more expensive but offers way better protection and convenience, especially in older homes where wiring can be dodgy.

Labelling

You’ll notice that labelling on CUs can be hit or miss. It’s really handy to know which fuse or RCBO controls which circuit, especially in an emergency.

If your CU isn’t well labelled, you can fix that yourself in about an hour. Grab some clean labels and a fine-tip pen. Go through each MCB one by one—switch it off and see what stops working. Jot down what each circuit controls and label accordingly.

Keep a record of this info near the CU; it could save you a lot of hassle (or even your life) later.
Plus, it’ll make things easier for any electrician working in your home.

If you have issues with your RCD not resetting after it has tripped, check out our handy post: Help, I have no Power

Electrical Safe Zones

Electrical Safe Zones

by | Aug 20, 2024 | DIY Electrical Advice, Practical DIY Advice

Electrical Safe Zones

Where is it SAFE to drill in a Wall?

This is a question we asked all the time on our DIY Courses.

Understandably, many people are worried about this. It stops them even picking up a drill.

So here’s what you need to know……..

There are 3 MAIN AREAS where you can definitely expect cables to have been run……

These areas are rather strangely called “SAFE ZONES” even though there is very little safe about them.

Image provided by Elecsa

1. Where two walls meet

An area 150mm (6 inches) wide along the top of the wall where it meets the ceiling.

2. Horizontally either side of an Electrical Accessory

Basically this means in a straight line either side of a socket/switch/fused spur/light fitting etc. The line is the height of the socket/switch.

It runs all the way to the adjoining walls, or an obstacle, such as door or window.

Its important to note that an electrical accessory can be a lot of things, including a Consumer Unit (Fuse Box)

Its very safe to assume that there will be lots of cables running up, down and sideways around a Consumer Unit, so think very hard before you bang a nail in to put a lovely picture above the Consumer Unit. 

3. Vertically above and below an Electrical Accessory

In a straight line above and below a socket/switch/fused spur/light fitting etc. The line is the width of the socket/switch/fitting. It runs all the way to the floor and ceiling.

Again the same applies to a Consumer Unit, so be very wary.

Very Important: 

If the wall is less than 100mm (4 inches) thick, then the safe zones operate on both sides of the wall. Bear this in mind when you are drilling from a different room!

Very Very Important:

Electricians have very strict rules about where they can run their cables, and have to document if they haven’t been able to stick to the rules.

If you have had some electrical work carried out, it is worth checking the Electrical Certificate (if you were issued with one) as it may have some information about any deviations from the rules. 

Electricians in the past did not have these rules. Cables could be, and were run in all sorts of odd places.

We have found cables run diagonally across walls, doing sudden 90 degree bends and all sorts, so beware. 

If you suspect that someone in the past has carried out some electrical DIY work in your house, it is quite possible that they did not know about Safe Zones. They may have run cables wherever was most convenient for them, not always in the safest place.

If your current consumer unit does not have a functioning, healthy RCD, in fact, if you have any doubts at all,

TURN OFF THE CONSUMER UNIT BEFORE YOU DRILL

Where is it safe to drill in a Ceiling?

The rule that electricians should follow is to run the cables through the joists, as close to the centre of the joist as possible, at a depth of at least 50mm from the top and bottom of the joist. i.e 50mm from the ceiling/floor.

It is not always possible to follow this rule. There are often existing holes and notches in a joist. It is extremely likely that in the past, cables will have been run all over the place.

It is also quite possible that cables can be lying on top of plasterboard ceilings.

Because it is not always possible to run cables this way, the current electrical regulations allow cables to be run outside the zones, provided they are protected by an RCD..

If the wiring in your house is old and/or you have a Consumer Unit which does not have an RCD, then you should be even more cautious. 

If you have any doubts…..

TURN OFF THE CONSUMER UNIT BEFORE YOU DRILL

Where is it safe to drill in a Floor?

As with ceilings, the rule that electricians should follow is to run the cables through the joists, as close to the centre of the joist as possible, at a depth of at least 50mm from the top and bottom of the joist. i.e 50mm from the floor.

It is not always possible to follow this rule. There are often existing holes and notches in joist, and it is extremely likely that in times past, cables have been run all over the place. It is also extremely likely that gas & water pipes have also been run under the floorboards through notches in the joists, (in which case, it is worth checking very very carefully first) 

Because it is not always possible to run cables this way, the current electrical regulations allow cables to be run outside the zones, provided they are protected by an RCD.

If the wiring in your house is old and you have a Consumer Unit which does not have an RCD., then you should be even more cautious

If you have any doubts…..

TURN OFF THE CONSUMER UNIT BEFORE YOU DRILL

How do I cut Copper & Plastic Pipe?

How do I cut Copper & Plastic Pipe?

by | Aug 10, 2024 | DIY Course

How do I cut Copper & Plastic Pipe?

Cutting Copper & Plastic Pipe

How do I cut copper pipe? is a question we are asked early on in our DIY Plumbing Courses

As those of you who have been on our Essential Home Plumbing Course will know, cutting copper & plastic pipe is pretty straightforward, once you know the technique.

We thought it would help to make a quick video to remind you of a couple of important tips whencutting pipe, and the differnt tools you can use.

If you still feel a bit wary about doing this, or would like a bit more practice, why not sign up for one of our DIY Plumbing Courses, or check out our DIY Assist Service (we come to your home and support you with your DIY projects)

Essential Home PlumbingDIY Assist

Using Compression Joints

by | Aug 10, 2024 | DIY Course

Compression Plumbing Fittings

As those of you who have been on our Essential Home Plumbing Course will know, Compression fittings can be a joy to use

They are great for DIY plumbing. We thought it would help to make a quick video to remind you of a couple of important tips when using the fittings.

If you still feel a bit wary about using them, or would like a bit more practice, why not sign up for one of our DIY Plumbing Courses, or check out our DIY Assist Service (we come to your home and support you with your DIY projects)

Essential Home PlumbingDIY Assist
Using Push-fit Fittings

Using Push-fit Fittings

by | Jul 28, 2024 | DIY Course, DIY Plumbing, DIY Plumbing Advice

Speedfit Pushfit Plumbing Fittings

As those of you who have been on our Essential Home Plumbing Course will know, these Speedfit fittings are really straightforward to use.

They are great for DIY plumbing. We thought it would help to make a quick video to remind you of a couple of important tips when using the fittings.

If you still feel a bit wary about using them, or would like a bit more practice, why not sign up for one of our DIY Plumbing Courses, or check out our DIY Assist Service (we come to your home and support you with your DIY projects)

Essential Home PlumbingDIY Assist
Choosing the Right Drill Bit

Choosing the Right Drill Bit

by | Apr 23, 2024 | DIY Advice, Practical DIY Advice

The whole issue of choosing a drill bit feels a bit of minefield. It doesn’t need to be.

We cover it on lots of our courses, so that you feel confident choosing the right drill bit for the right material.

Drilling into Wood

If you are just drilling into wood, you have a couple of choices…..

High Speed Steel (HSS)

HSS Drill bits

HSS Drill bits (High Speed Steel) are usually a gold colour or black.

The point should feel a bit sharp, but not painfully so. 

These are actually designed for metal, and they are great at drilling into metal, but they are also great for everyday drilling into wood, and can be used for plastics, as well.

They’re a great all-rounder. I generally buy them in packs of 5 from Screwfix, (in my favourite sizes). This makes them pretty economical to use. When they go blunt, I mark them up, and hang onto them to mark drill holes on plaster & masonry walls. 

If you’re using them in metal, then drill slowly and steadily. If you need to drill a large hold, start with a small hole, and gradually move up through the sizes. This gives you, the drill and the drill bits a fighting chance. 

 

Brad point Drill Bits

Brad Point Bits

You can also use a Brad Point Drill bit in wood. 

These have a really sharp point, which hurts when you press it into your finger (no need to try it, just take my word for it). They can only be used on wood, and possibly plastic, but use them on metal or masonry, they will go blunt immediately.

Image of Masonry Drill Bits

Drilling into Walls

When you’re drilling into walls, you will need Masonry Drill bits. 

These are often Silver-coloured or Gunmetal Grey. 

They don’t feel sharp to the touch, but have what looks like a reinforced point. This is because they will be drilling into a hard material, and can be used with a Hammer Drill. Basically they use both blunt force trauma & a cutting action at the same time, so need to be very robust. 

They’re not designed for using on soft materials like wood or plastic. If you do, you will probably just create an unpleasant burning smell. You can use them on plaster and plasterboard.

Drilling into Metal

Use HSS drill bits when drilling into metal  (that’s what they’re designed for).
Drill slowly, and don’t try using a blunt drill bit.
For larger holes, start by drilling a small hole, then slowly increase the size of the drill bit until you reach the right size.  Trust me, this may sound a bit slow and laborious, but it will be more successful more quickly.

Drilling into Plastic

For drilling into plastic, I generally use an HSS Drill bit (see how versatile they are). Plastic can get hot and melt, so make sure the drill bit is sharp, and don’t drill to fast.

Get more Practice…..

If you want to get some practice using Drills and choosing Drill bits, then why not try one of our Beginners DIY Courses. We will take you through the process slowly and clearly. You can have as much hands-on practice as you need …

Nailing it! DIY Beginners
DIY "Next Steps"
Drill Down into Drilling
Electric Showers – what you need to know

Electric Showers – what you need to know

by | Feb 2, 2024 | DIY Electrical Advice, Practical DIY Advice

Electric Showers – what you need to know

What is an Electric Shower?

Unlike traditional “Mixer” showers, electric showers only require a cold water supply, which they heat up instantly as you stand beneath the spray.

With a safety cut-out feature, you can enjoy your shower without worrying about getting scalded if the water supply suddenly drops.

Why choose an Electric shower?

Sometimes, a balanced supply of hot and cold water from a boiler may not be available in your home. In such cases, an electric shower is the ideal solution. It ensures that you always have a refreshing shower, regardless of the water pressure in your house.

So how do Electric Showers work?

Electric Showers  are directly connected to your cold mains supply and contain a heating element that warms up the water as it flows through, a bit like a sophisticated kettle.

The faster the water flow, the more power the shower needs to heat the water up. This is why it’s essential to have a properly installed electric shower with the correct cable size to prevent overheating and potential hazards.

This is where one of the main safety issues surrounding Electric Showers becomes apparent.

Fitting an Electric Shower is NOT a DIY project

We’re going to keep saying this….

Who should fit an Electric Shower?

*When it comes to fitting an electric shower, it’s crucial to seek the expertise of an Electrically Competent Person*. 

(*This is actually a defined term, which means someone who has sufficient knowledge and training to comply with Part P of the Building Regulations.)

With their knowledge and training in compliance with building regulations, they will ensure a safe and efficient installation.

Should an electric shower be installed by a Plumber, an Electrician or maybe a Handyperson? 

There’s no easy answer. Water and Electricity mixed together can be very dangerous. Because of this, Bathrooms are regarded as “Special Locations” for electrical work. What we can definitively say, is that an electric shower must be installed by an Electrically Competent Person. 

Fitting an Electric Shower is NOT a DIY Project

….nor is it a job for an unqualified Handyperson….

What size Electric Shower should I choose?

So, there you are shopping in one of those lovely DIY stores, where there is a range of shiny new electric showers on display.

You need to replace your shower; its got a bit drippy, is looking a bit limescaly, or has gone that lovely yellow-plastic colour through age.

Time for an upgrade!

So many different sizes to choose though. Surely the more powerful the shower, the better showering experience you’re going to have. 

This is where the DIYer can come seriously unstuck & put themselves & others in Danger

However the choice may not be down to you. The decision will be dictated by several things:

  • The size & quality of the cable supplying the electric shower
  • The length of the Cable run from your Consumer Unit (Fuse box)
  • The material through which the Cable runs.
  • (I have seen cables melted because they are running through newly-installed Loft Insulation)

These are all questions which an Electrically Competent Person is going to consider, before advising you which size shower to choose.

You may not even know that you should be asking these questions, let alone how to find out the answers.

The most powerful electric shower will generally need a very big cable. This will increase in size, as the length of the cable increases.

As a rule of thumb, Big Cables are much more expensive than smaller Cables!

If your existing electric shower has been there for a long time, the chances are that it may only be supplied by relatively small cable, which will not cope with the demands of a more powerful shower. You may need a whole new, much larger cable, to be installed. 

Installing new cables can be disruptive, messy & expensive.

Does the person installing your Electric Shower know this?

The Dangers of Loft Insulation

Loft Insulation is generally a very good thing. We should all be making sure that we insulate our lofts. It will keep heat in, make our houses more thermally efficient and save us money.

However, electrical cable and insulation need to be thought about carefully. If you cover all the electrical cables in your loft with insulation, this may affect the cable’s ability to carry current.

When the cables were originally installed, there may not have been very much insulation in your loft, so the cables were fine.

Now that your loft has 150 or 200mm of lovely warm insulation lying over the top of it, the cable is no longer able to do its job properly.

Cables supplying Showers are particularly at risk. On several ocasions I have found shower cables in lofts showing signs that they are melting. Even the cable clips have begun to melt.

This is very dangerous. I have spoken to people who install insulation in loft spaces for a living, who were unaware that this is an issue that they should be aware of, and taking into account during their insualtion.

I’m sure many of us have seen the Loft Insulation Installations carried out “under grant” where it looks as though the loft insulation was installed, by throwing it liberally  about the loft from the loft hatch. I’m prettty confident that the well-being of any cables being covered by the loft inulation was not a consideration.

Important Messages

  • Seek advice from an Electrically Competent Person before replacing an electric shower.
  • Make sure you choose the correct person to install an Electric Shower. If you ask for a quote from an Electrically Competent Person, and then find someone who "can do it cheaper," please make sure that they are competent.
  • If you are insulating your loft, please make sure that you are not covering up cables and creating a potential fire-hazard
  • Installing an Electric Shower is NOT A DIY PROJECT

Fitting an Electric Shower is NOT a DIY Project

How old are your Smoke Detectors?

How old are your Smoke Detectors?

by | Jan 20, 2024 | DIY Electrical Advice

Which Birthday will your Smoke Detectors be celebrating this year?

Are your Smoke Detectors still looking gleaming white?

If they are beginning to take on that yellowing plastic look, it may be that they are approaching, or possibly have already celebrated, their 10th Birthday without you even noticing.

I know, I know, another one of those things that you need to check. There seem to be so many these days.

Anyway, back to the Smoke Detectors….

Generally Smoke & Heat Detectors are regarded as a “Good thing.”

You may not feel quite so well-disposed towards them when they start chirruping at you at 3 o’clock in the morning to tell you that their back-up battery is flat, but when they are just getting on with their job, they’re definitely a good thing.

In fact they’re such a good thing, that we electricians are required to install them a lot more often these days.

Very importantly, Landlords are required to make sure that they are installed and working properly in their rental properties.

This is probably something to do with the fact that they save lives.

Inter-connected Smoke Detectors

Nowadays, we encourage people to install inter-connected mains-operated detectors with a back-up battery.

Inter-connected means that if one detector is activated, the rest of them all join in and make sure that there’s absolutely no way that you can sleep through the issue.

Mains-operated means that they aren’t going to stop working, just because the battery has gone flat, or you’ve removed the battery in a rage in the middle of the night, and forgotten to put it back.

Why replace Smoke detectors?

Unfortunately, like a lot of good things, Smoke Detectors have a shelf life. In the case of Smoke & Heat Detectors, this is about 10 years, but can be as low as 7 years. They should have a date of manufacture and Expiry Date somewhere nice and visible.

It may be time to get a step ladder out just to check.

If the expiry date is in the past, then it’s time to replace your Smoke & Heat Detectors.

Many of the quality makes of Smoke & Heat Detectors allow you to retro-fit with very little effort.

Basically you can leave the base connected in the ceiling, so don’t have to touch the wiring, then slide or twist the detector off the base, and replace it with a new one.

Job done! No electrician required.

 

Why are there different types of Detector?

It can be a bit confusing, but here’s a quick summary….

Heat Detectors

Heat Detectors are designed to go in your Kitchen, Garage, or dusty areas. As the name suggests, they wil be triggered by an increase in heat, approx 55 degrees. They are not going to be set off by you burning the toast, or your Sunday Roast. They are less susceptible to dust than Optical and Ionisation Smoke Detectors.

Ionisation Smoke Detectors

Ionisation Smoke Detectors are the old style smoke detectors. They are being phased out and replaced by Optical Smoke Detectors. They are most sensitive, and are a bit more prone to false alarms.

Optical Smoke Detectors

Optical Smoke detectors  are replacing the old Ionisation Smoke Detectors.

Ideally they should be installed in Bedrooms, Hallways, Living spaces (except Kitchens).

They will detect smouldering smoke, but are sensitive to dust, so if you need to install a detector in a dusty area, then you should use a Heat Detector instead.

Replacing old Smoke Detectors

Some makes and models of smoke detector have stopped being manufactured. This can be annoying  if you want to leave the base in position and just replace the detector itself, without calling in an electrician.
Safelincs have a useful guide to compatible makes and models on their website.
Not all makes and models are replaceable, but some are, so its worth checking, just in case. It could save you some money.

Upgrading yor Smoke Detectors

If you need to upgrade your Mains-operated Smoke detectors, you will need to call an electrician in. 

We often fit AICO Detectors, because AICO make it easy for customers to retrofit detectors in the future.  They also make it easier to add additional Detectors in areas where it would be awkward or expensive to run new wiring.

Basically they allow you to create hybrid systems with mains and battery-operated detectors talking to each other.

They also have a range of Smart Detectors for those of us who like our doorbells and washing machines to chat to us on our mobile phones while we’re away from home. An exciting world of conversations with your smoke detectors awaits you, if you decide to go down that route.

Anyway, back to the point. Please check your Smoke Detectors and make sure that they are still in date. If they aren’t, please do something about it. Don’t leave it until it’s too late.

At the risk of sounding a bit doom laden, anyone who charges a battery in their home, particularly a larger battery for a bike or scooter, has the potential for an issue, so please…

MAKE SURE YOU ARE PROTECTED

Boiler Condensate Pipes

Boiler Condensate Pipes

by | Dec 1, 2023 | DIY Plumbing Advice, Practical DIY Advice

Protect your Boiler from Freezing

As we approach the end of Autumn the air of late is definitely feeling chilly! Jack Frost had well and truly put his stamp on the grass this Saturday morning at my local park.

With this change in the weather most of us will by now been getting used to putting the heating on. Now is the time to get your boiler serviced as it approaches its most hard working period of the year to check everything is in tip top condition when you need it most. Before we get too close to the festivities get your boiler service booked with a reliable Gas-Safe registered engineer.

 

There is something YOU can do…… 

……… particularly if you have any crazy pipework like that shown in the picture above.

Most modern combi boilers have a small plastic pipe that carries waste water away from the boiler. Ideally, this should terminate internally, but if it does run outside, there are 3 things which should be done:

  • The pipework needs to be lagged
  • The pipe diameter needs to be upgraded by at least one size. (i.e the  condensate pipe needs to be upgraded to at least 32mm waste pipe)
  • The overall pipe run should be as short as possible.

If this pipework freezes and your boiler can’t get rid of this water it will stop working probably at the most inconvenient time.

Limit the chances of this happening by getting busy with some lagging and plastic cable ties.

Armaflex (black coloured) lagging is recommended as it is designed for outdoor installations.

What to do if your Condensate Pipe freezes

1. Pour Warm water over the Pipe

This is easier to do, if the pipe is outside.
Be careful that the water which lands on the ground doesn’t freeze and cause a dangerous slip hazard

2. Use a Hot Water Bottle or Hairdryer (on low heat)

This is easier to do, if the pipe is inside.

So, before you suddenly discover that your boiler isn’t working properly, and your home is getting very cold, go and check that your condensate pipe is Cold Weather Ready

How to re-pressurise a Boiler

How to re-pressurise a Boiler

by | Jul 5, 2023 | DIY Plumbing Advice, Practical DIY Advice

How do I know my Boiler needs re-pressurising?

In most cases, you will suddenly discover that you have no hot water or heating, and your boiler is not working.

There are many things that cause a Boiler to stop working. Many of them will require an engineer to come out and repair the fault. However, by far the most common issue to stop a boiler working is a drop in boiler pressure. This is something that you can rectify yourself. (If there has been a suddent drop in temperature outside and the weather is freezing, check out our advice on Freezing Condensate Pipes as well)

In fact the pressure on your boiler is something that you really should be aware of and check on a regular basis. If the pressure is constantly dropping and you are regularly having to re-pressurise your boiler, that indicates that there is an underlying problem, and you should call in a Gas-Safe Engineer to investigate and rectify the problem.

Most Boilers have some kind of pressure gauge on them, which gives you an indication of the boiler pressure. They usually have a helpful Green section which indicates a safe operating pressure, and a  Red section, which indicates that the pressure is too high or too low.

They also often have some lines, to indicate a normal pressure. The needle should be slightly above this normal level, or, on some dials, between 1 & 2.

If the needle has fallen below 1, (or the line),  then the boiler pressure is too low and needs to be increased.

 

If the needle is in the high Red section, your pressure is too high. The boiler should rectify this problem itself by dumping (usually very hot) water out of the system through a Pressure Relief Valve. You may see this happening on an outside wall of your house. If this does happen, turn the boiler off and call an engineer.

How do I re-pressurise my Boiler?

If you’re lucky (organised) enough to still have the manual that came with your boiler, the instructions will be found there.

Failing that, there is a lot of information on the web to help with re-pressurising your boiler. Each make (and sometimes model) of boiler is different, so it is not possible to give a one-size-fits-all explanation.