Gas Safe 400km Cycle Challenge Helps Raise Over £34,000 for Charity

On 19th September 2019, Richard and Adam of Gas Safe Bristol joined a team of 20 riders embarking on a 400km bike ride between two of Europe’s most iconic landmarks – the Clifton Suspension Bridge in Bristol and the Eiffel Tower in France.

4 days of battling with unpredictable weather, punctures, saddle rash and angry wasps sure took its toll, but was worth the pain with the two Gas Safe riders raising £2,000+ towards a huge £34,000+ total donation to a charity close to their hearts.

Find out more about the ride, the route and the very deserving cause the money went to.


Recent Gas Combi Boiler Installation

New Gas Boiler installation
All Our engineers are highly trained and Gas Safe Registered. The picture attached is from one of our recent Gas Combination (Combi) boiler replacements. As you can see the new Vaillant gas boiler looks more modern than the old one adding to the modern look of the kitchen. Our client was very happy with work carried out and the improvement of hot water pressure the new Vaillant gas boiler has given them. This job was completed in just one day and the system was Chemically Power Flushed. Our gas safe registered engineer removed the old boiler from the property along with all the packaging from the new gas boiler. Inhibitor was added to the system water to help prevent corrosion inside the pipework, boiler and radiators. New thermostatic radiator valves were installed to the radiators to help control the temperature in each room. A programmable room thermostat was installed in the hallway to help prevent the house from over heating. All controls were shown and demonstrated to our client so they know how it use them.

This boiler comes with a 7 year warranty that covers parts and labour.

boiler being serviced by gas safe engineer

Why Should You Have Your Gas Boiler Serviced?

Having your Gas boiler serviced annually is essential to guaranty the safe and efficient operation of your appliance. Your boilers warranty may also be void if the appliance is not serviced each year. Here at Gas Safe our engineers are trained to maintain all different makes of boiler. Valliant, Worcester, Baxi, Ideal, Potterton, Viessmann, Vokera, Glow-worm – are all makes of boiler we work on.


Combi boiler situated in family kitchen

What Is a Combi Boiler?

A combination boiler or combi boiler is a gas central heating boiler that is also an instantaneous water heater. A combi boiler is an ingenious space-saving idea, and an increasingly popular choice in UK homes. In fact, combi boilers now account for well over half of all the new domestic boilers installed in Britain every year.

A combi boiler is both a high-efficiency water heater and a central heating boiler, combined (hence the name) within one compact unit. Therefore, no separate hot water cylinder is required, offering space saving within the property.

Further benefits of a combi boiler includes hot water being delivered through your taps or shower at mains pressure. So you can enjoy powerful showering* without the need for a pump.

Another combi boiler benefit is that it can generally save you money on installation time and costs, since no tank in the roof space means less pipe work and a shorter installation time.

How Does a Combi Boiler Work?

A Combi boilers works the same as a standard boiler by burning gas and producing heat. This heat is then used to warm the water passing through the boiler using a heat exchanger. With a standard boiler that water would then flow through your radiators or hot-water cylinder. A Combi boiler works differently by having a second heat exchanger that transfers heat from the main heat exchanager to the mains cold water passing through the boiler when a hot tap is tuned on.

What Are The Benefits of a Combi Boiler?

  • Lower Energy Bills – With efficiency of 90%, for every £1 you spend on energy, only 10p is wasted. When you consider that some of the older non-condensing boilers only reached 55% efficiency, it represents a significant saving. For example, when replacing a boiler with less than 70% efficiency with one of the most efficient condensing units you could save up to £305 on your heating bills in one year.*
  • Compact Size – Imagine finally being able to get rid of that bulky water tank and / or storage cylinder that sits in your attic or airing cupboard. A Combi boiler is just one simple unit and some are small enough to be concealed in a kitchen cupboard. This is particularly great news for those living in small homes or flats.
  • High Energy Efficiency – A Combi boiler is typically over 90% efficient which is the highest level of efficiency on the market, helping you to reduce your carbon footprint.
  • Hot Water On Demand – There is no need to store hot water which means less energy used and none of that inconvenient waiting around for a hot water tank to refill.
  • Mains Pressure – A Combi boiler takes its water supply directly from the mains which can often mean you get a much stronger pressure of hot water through your taps and showers.
  • Easy To Install – As there’s no need for multiple elements a Combi boiler is usually simple to install and, unlike system or conventional boilers, it can be fitted anywhere in the home.

What To Consider

Make sure you have an adequate supply of water coming from the mains. If the mains pressure is weak or inconsistent, your showers and taps will be too. This single flow of water is also a problem if you have several showers, baths and sinks that need to be used simultaneously as the flow will try to split between them all and weaken as a result.

If you have a higher demand for hot water then a high efficiency, condensing system or conventional boiler may be the answer.

All condensing boilers require a condensing pipe to drain the condensed vapour and dispose of it down a drain. If the installer can’t add a pipe where the existing boiler is positioned then it may need to be relocated; this may add to the cost of installation.

Who Are The Leading Manufacturers of Combi Boiler?

The main manufactures of combi boilers in order of our own recommendation are:

  • Vaillant
  • Worcester
  • Viessmann
  • Ideal
  • Baxi
  • Vokera
  • Potterton
  • Glowworm
  • Biasi
  • Ferroli

The Drawbacks of Combi Boilers

Despite the popularity of combi boilers, there are several issues that you should bear in mind when considering replacing your boiler.

The disadvantages of combi boilers include:

  • Dependence on Mains Pressure – To ensure that your combi boiler is working properly, you need good mains pressure. If you are having a new boiler fitted, you should check what the mains pressure in your area is before you go ahead with the installation.
  • Limited Use – With a combi boiler it is not possible to run more than one shower or bath at a time, or to turn on the hot tap while showering. This may be an issue if you live in a large house with a number of bathrooms and en suites, or with lots of people.
  • No Immersion Heater – As there is no water tank, if your combi boiler breaks down then you will be left without hot water as well as central heating (unless you install an electric shower).
  • No Power Shower – You can’t have a power shower with a combi boiler, as the water pressure is set by the pressure level at the water mains.

Combi Boiler Installation Bristol

At Gas Safe Bristol, we provide a complete combi boiler service including installation, emergency repairs and servicing. If you need a combi boiler installed, or aren’t sure which boiler to go for, we can help. Call one of our team today on Bristol: 0117 964 0078 , Somerset: 01934 811 566 or fill out a contact form and we’ll get back to you.

Woman using central heating system

New Gas Boiler Needed?

Buying a new boiler tends to be a decision that most people need to make in a hurry. Usually, your old boiler has broken down, it’s the depths of winter and you need to get your hot water and central heating restored to its former working glory.


Landlord Safety Testing

Boiler servicing for landlords

As a landlord you should be aware that you are responsible for the safety of your tenants. Your legal duties apply to a wide range of accommodation occupied under a lease or licence, including (but not limited to):

  • Residential premises provided for rent by local authorities, housing associations, private sector landlords, co-operatives, hostels.
  • Rooms, let in bed-sit accommodation, private households, bed and breakfast accommodation and hotels.
  • Rented holiday accommodation such as chalets, cottages, flats, caravans and narrow boats on inland waterways.

The Gas Safety (Installation and Use) Regulations 1998 outline the duties of landlords to ensure gas appliances, fittings and chimneys/flues provided for tenants are safe.


Your responsibilities

If you let a property equipped with gas appliances, you have three main responsibilities under UK law:

  1. Maintenance: gas pipework, appliances and chimney/flues need to be maintained in a safe condition. Gas appliances should be serviced in accordance with the frequency given in the manufacturer’s instructions. If these are not available, annual servicing is recommended unless advised otherwise by a Gas Safe registered engineer. Any gas appliances owned by tenants are not the landlord’s responsibility, however the connecting pipework and flue (if not solely connected to the tenant’s appliance) remains the responsibility of the landlord to maintain.
  2. Gas safety checks: gas appliances and flues must be safety checked annually by a qualified Gas Safe registered engineer. New regulations introduced in April 2018 allow a landlord to arrange for a gas safety check to be carried out any time from 10-12 calendar months after the previous check whilst still preserving the original check expiry date. Where a gas safety check is carried out less than 10 months or more than 12 months after the previous gas safety check this will have the effect of ‘resetting the clock’ and the new deadline date will now be 12 months from the date of this latest gas safety check. Landlords are not responsible for safety checks on gas appliances owned by the tenant or any flues that solely connects to tenants own gas appliances.
  3. Recorda record of the annual gas safety check should be provided to your existing tenants within 28 days of completion, or to new tenants upon the start of their tenancy. If the rental period is less than 28 days at a time you may display a copy of the record in a prominent position within the dwelling. You’ll need to keep copies of the record for at least 2 years. If you have benefited from the new regulations allowing flexibility in timing of gas safety checks, records must be kept until two further gas safety checks have been carried out.

Additional info: It’s a good idea to ensure that your tenants know where/how to turn the gas off and what to do in the event of a gas emergency. Last, but certainly not least, make sure anyone carrying out gas work on your property is Gas Safe registered and qualified to work on the type of gas and appliances provided – this is not only the law, but the most important step to ensuring the safety of your tenants.


Any issues?

Some landlord/tenant relationships can become problematic. The tenancy agreement should allow access for any maintenance or safety check work that needs to be carried out. However, if your tenant refuses to give you access to the property you must show that you’ve taken all ‘reasonable steps’ to comply with the law – such as repeating attempts to carry out the safety check and writing to the tenant explaining that a safety check is a legal requirement that is in place for their own safety. Be sure to keep a record of any action taken as you may need this at a later date. The Gas Safety (Installation and Use) Regulations do not give powers to ‘force disconnection’ of the gas supply in these circumstances and you may need to seek legal advice.


Short term lets

If you let a property for a short period of time (e.g. a holiday home for a week) you still have gas safety duties as a landlord. 

Why do we use thermostatic radiator valves

Thermostatic Radiator Valves (TRVs)

What are thermostatic radiator valves (TRVs)?

Thermostatic radiator valves are commonly referred to as TRVs and are used to control the air temperature of different rooms – you will normally find them on the side of your radiators.

TRVs are just one of a number of heating controls, which allow homeowners to heat their homes more efficiently. If set up correctly, they allow you to have different heating zones throughout the house, despite only one centralised boiler providing the heat.

How does a TRV work?

The TRV is a self-regulating valve that works by changing the flow of hot water into a radiator. It consists of two parts, the valve head and the valve body, with the head sitting atop the body. Myson TRV bodyWhen the room temperature changes, a capsule in the valve head contracts or expands, which moves a pin in the valve body causing it either to open or close.

If it gets too warm in the room, expansion of the capsule will cause the pin to close the valve – slowing the movement of hot water into the radiator. Likewise, if the room drops in temperature, contraction of the capsule in the valve head pulls the pin out, allowing hot water to enter the radiator once more.

There tends to be two materials used in the TRV capsules – wax or liquid. On the whole, liquid models are generally considered to be better and their price reflects this. One of their advantages is their responsiveness to changes in temperature – while the wax one is relatively slow to expand or contract, the liquid capsule will change the flow of water into the radiator far more quickly.

Costs of TRVs

A TRV will cost you about £10 – 30 each. The Drayton TRV4 for example, which is a liquid capsule TRV and is considered one of the best costs £20 from Screwfix. Installation cost will very depending the system. A full drain down is usually needed and can take some time. Inhibitor is then needed when filling the system back up.

Where not to use a TRV

There are two places that you really shouldn’t install TRVs on the radiators – the first is in bathrooms. This is because the heat produced by the bath/shower will cause the TRV to shut off (it will cause the capsule to expand), just when you need the heat from the radiator to fight off condensation.

We also don’t advise installing a TRV in the same room as your main heating thermostat. The main thermostat will link directly to the boiler, firing it up or turning it down, so by having a TRV in that room they will fight for control – if the TRV wins, the heating in your house will go off!

Newer electronic TRVs

electronic TRVNowadays you can take zonal heating control a step further with electronic TRVs (for example Honeywell’s Evohome system). These electronic TRVs use batteries and electronic thermostats to constantly monitor the temperature of the room and move the pin up and down accordingly.

They can also be used with the other heating control components to create an intelligent heating system like the Heat Genius system. This obviously adds significant cost to the system, but allows you to accurately monitor and control the temperature of individual rooms in the home all from the touch of the button on your tablet computer or phone.

Are TRVs a good idea?

In properties with a decent number of different rooms, then TRVs are definitely worth considering, especially if there are rooms that are unused and therefore not worth heating in the first instance.

They can produce decent energy savings especially when part of an intelligent heating system.

It is important to maintain them though; many clients we see have non-functioning TRVs.

It is important to ensure that the valve head vents don’t get clogged by dust and other objects since this can obstruct air hitting the liquid or wax capsules that control how the TRV functions. It is also worth checking once a year that the pin in the valve body is still moving freely (these sometimes get stuck).

To do this, unscrew the valve head off the body – this should reveal the pin that moves up and down controlling the flow of water into the radiator. A spring should hold the pin fully extended above the valve – if the pin doesn’t move when you push it, you may need to replace the whole valve assembly.

Save money by installing a programmable room thermostats

The average household spends more than £1,200 a year on energy bills – nearly half of which goes to heating. Homeowners can save about £120 a year by properly setting their programmable thermostats and maintaining those settings

A programmable thermostat helps make it easy for you to save by offering four pre-programmed settings to regulate your home’s temperature in both summer and winter – when you are home, asleep, or away.


Programmable thermostats have become hugely popular due to their energy saving benefits, improved comfort, convenience and cost – effective savings. These thermostats save energy and money on utility bills by allowing residents to set home temperatures according to various different factors.

Programmable thermostats supply personal comfort through pre-set temperature levels and are generally more convenient and accurate than manual thermostats.

Programmable thermostats are also a plus for the environmentally conscious because they contain no mercury and are eco-friendly. Using less energy helps to reduce greenhouse gas emissions associated with energy production.

For homeowners who work outside the home during the day and have a different schedule on the weekend, a programmable thermostat can offer many benefits. On the other hand, if you are home throughout the day, seven days a week, then a programmable thermostat will offer more limited benefits.

  • The pre-programmed settings that come with programmable thermostats are intended to deliver savings without sacrificing comfort. Depending on your family’s schedule, you can see significant savings by sticking with those settings or adjust them as appropriate for your family.
  • The key is to establish a program that automatically reduces heating and cooling in your home when you don’t need as much. Use the programmable thermostat calculator to see what you can save with set-back temperatures that work for your family. The pre-programmed settings for a programmable thermostat are:

SettingTimeSetpoint Temperature (Heat)Setpoint Temperature (Cool)
Wake6:00 a.m.≤ 70° F≥ 78° F
Day8:00 a.m.Setback at least 8° FSetup at least 7° F
Evening6:00 p.m.≤ 70° F≥ 78° F
Sleep10:00 p.m.Setback at least 8° FSetup at least 4° F

Programmable thermostats can be set to adjust the temperature of a home according to a user’s schedule. The temperature on programmable thermostats can be set to change based on whether or not the home is occupied or whether residents are asleep or awake. For example, in the morning before occupants wake up, the thermostat can be preset for a slightly warmer temperature. As well, the thermostat can be adjusted for both heating and cooling seasons.

Programmable thermostats can automatically store settings and repeat those settings each day. However, they can still be manually set, overriding the programming when desired. A programmable thermostat generally allows more precise temperature management and a wider range of selections, offering a number of programming choices.

Most conveniently, it provides daily programming that allows one schedule to be used each day. Additionally, you can program your thermostat with different settings for the weekend. In fact, most programmable thermostats have a full seven-day programming ability, allowing for a different temperature schedule for every day of the week.

Contact Gas Safe if you are interested in having a digital programmable thermostat installed in your home today.

A Guide to choosing a new gas boiler

The first step is to decide which boiler is best for you: combi (short for combination) or system? Combi boilers – Britain’s best-selling type of boiler, as they are compact and quick to install – provide heat for your radiators and hot running water on demand. They don’t need a water storage cylinder and so take up less space, making them ideal for smaller properties.

For larger households, however, system boilers will be the answer, or for those seeking the convenience of being able to run hot water from more than one tap at a time.

To ensure you have enough hot water for your family from a standard single-coil cylinder, the rule of thumb is to allow 25 litres per person per day. We do, however, recommend that all new installations have a twin-coil cylinder instead, to futureproof the home for the potential retrofitting of a solar thermal or renewable heating system.

It’s also worth considering upgrading from a gravity-fed system (where pressure is generated from a cold water tank, often placed in the loft) to a four-pipe system. While most boilers in the UK have two pipes, which provide hot water and heating concurrently, Worcester and Vaillant set-up uses four pipes to deliver hot water separately to both heating and hot water circuits. In doing so, the boiler prioritieses hot water to ensure its immediate availability and heating water temperature is reduced so the boiler fully condenses most of the time. As a result, a lower output, more affordable boiler can be installed that uses less energy.

Types of Boiler

Combi Boiler

How they work:

Combis work as sealed systems, providing hot water for both the taps and central heating system, heating the water directly from the mains as and when it is needed — meaning there is no need for a hot water storage cylinder, or a cistern in the roof space.

Advantages: Combis are quicker, easier and cheaper to fit than system boilers, as well as space saving due to the lack of a cylinder or cistern. Water is delivered at mains pressure, so you can enjoy a more powerful (although not ‘power’) shower.

Disadvantages: It’s a priority system, so it only satisfactorily deals with one heating need at a time. While fine for small families with one bathroom, larger families will experience poor flow rates when multiple outlets are used at once. Performance is also dependant on the diameter of the pipe entering the property: if it’s less than 22mm, then a combi is a bad choice.

System Boiler

How they work:

System boilers are fitted to sealed heating systems, but unlike combis work on the principle of storing hot water in a cylinder, so they can feed several outlets at once at mains pressure. There’s no need for a cistern in the loft and the expansion vessel is built in.

Advantages: Ideal for larger homes with higher demands, and as they have most of their major components built in (i.e. expansion vessel and pump), installation is quicker, cheaper and neater. Flow rates are usually high as water is delivered at mains pressure, and hot water is instantaneous.

Disadvantages: Will run out of hot water if overused. Some installers claim they are more complex and prone to problems than regular boilers, such as pressure loss.

Regular/Conventional Boiler

How they work:

Regular boilers are now largely bought as replacements for homes with an open-vented heating system (i.e. supplied by means of a feed and expansion cistern in the roof space, meaning the system is open to air). Like system boilers, they work on the principle of stored water and require a separate hot water cylinder.

Advantages: The water out of the taps will be at a good flow rate (not to be confused with pressure) and hot water can be supplied instantaneously. This is the ideal setup for a ‘power’ shower, which requires a cold water feed from the cistern and a separate electric pump.

Disadvantages: They’re more expensive to install, needing more components and pipework, and also take up more space. They can suffer from low pressure if the cistern is not located high enough, meaning additional shower boosters may be required. Hot water can run out.

Note: Sealed or Open? In a sealed circuit, the system is filled to approx 1 bar pressure and then sealed. Unlike an open-vented system, there is no cistern, so an expansion vessel handles excess water. Sealed systems are more efficient.

Shop the selection of boilers in our product directory

Heating Controls

Improvements to boilers have been matched by advances in their controls. Rather than the traditional single thermostat in the hallway, intelligent zoning controls enable different temperatures and timing programmes to be set around the house, avoiding heating empty rooms. You can also remotely control and monitor energy usage using a smartphone app.

Weather compensation controls can boost the efficiency of a condensing boiler by as much as 15 per cent. Thanks to a small sensor on the exterior of the building, the boiler increases or decreases the radiator temperature to compensate for outdoor temperature changes. These small adjustments consistently maintain the room at your chosen temperature, regardless of a temperature drop or rise outside.

There is a common misconception that weather compensation controls can’t be fitted on old properties in order to boost the boiler’s efficiency. Actually they can, as long as the installer has correctly set the boiler’s operating gradient. This is largely determined by how well the property is insulated.

We take our time choosing a new car, considering which will be most economical to run or comfortable. We live with our boiler for much longer — so it pays to invest the same efforts in your heating system.

An important footnote: Make sure you use an installer on the Gas Safe register

Getting the Right Size of Boiler

It was once common practice to oversize boilers by around 30%, but nowadays this is considered wasteful, making it important to specify the right size for your home. This is decided by means of a heat loss calculation and will be affected by the house’s size, the materials used and the level of insulation and airtightness, as well as your hot water requirements, i.e. how many bathrooms are there? A heating engineer can work this out for you, but you can also use a free online calculator — try the one at

Once you know the heating requirements of each room in kilowatts, you can size your heating emitters – i.e. radiators or underfloor heating – then you will know the boiler you buy will be big enough to heat the whole system efficiently.

Condensing Boilers

Before the advent of the condensing boiler, the heat contained within the combustion products that were discharged from the boiler – which could be anything up to around 180°C – were simply wasted.

Condensing boilers were designed with the purpose of extracting as much of the heat energy in the fuel as possible, and turning it into useable heat to warm the house. This means they burn less fuel for the same amount of heating.?Since 2005, condensing boilers have been made compulsory by the Building Regulations for new domestic central heating boilers.

Where to Position it

Boilers are ideally positioned on the ground floor in houses (a requirement for oil-fired boilers), within the kitchen or a utility area. Careful consideration must be given to the position of the flue as condensing boilers produce a plume of steam which can be a nuisance. See the Building Regulations Part J for detailed advice and diagrams.

Integrating Renewables

A well-sized solar water heating system could provide up to 60% of your annual hot water requirements, but careful thought needs to be given to how the central heating system will work as a whole. Firstly, you must buy a compatible boiler — not many combi boilers work with solar, but most regular and system boilers will be fine. Secondly, you will require a twin-coil cylinder, which will be heated via heat exchangers from both the boiler and the solar system. If hot enough, the volume of stored water can be fed directly to the tap (i.e. 60°C plus). If the water is not up to temperature, the boiler compensates, using less fuel overall.

Ground-source heat pumps are often designed to be the sole source of heating and hot water in the home, but many models can be configured to take a supplementary heat source such as an oil or gas-fired boiler.

Buying the Best Boiler

It’s important to buy the most efficient boiler you can, close to 90% (check, in an appropriate size. Aim for at least a five-year warranty. The boilers that work to the highest standard are the fan-assisted room-sealed type — i.e. it takes air from outside the building and combustion products are forced out using a fan.

Improving Efficiency

“Boilers are Only Part of the Story”

Tim Pullen, an expert in sustainable building, explains why you have to think of your whole heating system when aiming for energy efficiency

A-rated gas and oil-fired boilers are now close to, or over, 90% efficient, so there is not a great deal of room for improvement. To increase overall efficiency we have to look beyond the boiler.

Typically boilers run at a single flow temperature, which will be right for either the central heating or the hot water, but not both. Add a heat pump or solar thermal panels and the temperature mix gets even more complicated. This can mean mixing cold water to get the desired temperature, which is wasting a lot of heat.

A more sensible option is to install a thermal store which will store water at a different temperatures from the top to the bottom of the tank. This can allow the boiler to run at its optimum efficiency and deliver water to the central heating or tap at the right temperature.

Central heating controls are obviously essential. The ubiquitous room thermostat with a timer is the bare minimum, improved with radiator thermostats or, even better, zone controls. These allow time and temperature control for each zone or room, ensuring that rooms that are not occupied are not heated at the same time or to the same temperature.

Distribution System

A good boiler needs a good heating distributions system. An old central heating system can get furred up and sludge collects in the bottom of radiators. A new boiler will be more efficient, but cleaning the system and adding anti-furring liquid will only help.

It is difficult to predict a time when gas and oil-fired boilers will disappear, and equally as difficult to predict that they will get much closer to 100% efficiency. It would also be brave to predict that oil and gas prices will go against history and start falling. Minimising fuel consumption in the first instance is the key priority. An A-rated boiler is a start, but it is only a start.

It is becoming increasingly difficult to believe that a single boiler using a single fossil fuel energy source is a long-term, sustainable option. Renewable energy is also having an impact on the housing market, particularly among self builders and renovators. The heating industry have recognised that there are advantages to bivalent systems and have developed control systems that enable two heat sources to operate in happy unison.

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Gas Safe are one of Bristol’s leading plumbing and heating contractors. Established in 2005, they are a family owned company that pride themselves on a great reputation.