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Understanding Radiators & Radiator Valves

When it comes to radiators and valves, on the surface they may look quite complicated but when you get down to it, they are quite straight forward devices and are easy to understand once you are familiar with the terminology. In this guide, we'll take you through the different types of radiators available, the components they use and provide an overview on radiator valves. We'll also provide a basic overview on how radiators work.

How do Radiators Work?

Radiators work through a heat transfer process called convection. When water in the radiator is heated, the surrounding air is also heated up via convection and this hot air is then moved around the room as the air circulates.

Radiators are normally connected to a central heating system via pipes and hot water flows through these pipes and into the radiators themselves transferring hot water into the radiator. As mentioned, this hot water heats the room via convection. The hot water doesn't remain in the radiator, instead the hot water flows through the radiator and out again to the next radiator in the chain. As the hot water flows through the system it starts to cool down. When it flows back to the boiler the water is in a cooler state, and the boiler then reheats the water. The process repeats so long as the system is turned on.

As the radiators in the central heating system are connected in a chain, the radiator closest to the boiler is exposed to the water when it is at its hottest, whilst the radiator at the end of the chain, located just before the hot water returns to the boiler will be exposed to the coolest water. Because it is desirable to have all the radiators operating at the same heat output a process called balancing is used to ensure that the radiators all work to a similar temperature. Balancing works by restricting the flow of the water into a radiator. The balancing process is carried out by adjusting a valve called the 'lockshield valve'. Either by restricting or opening the flow of water into the radiator.

What is a Lockshield Valve?

A lockshield valve is a type of valve that is fitted onto every radiator at the side where the water flows into the radiator from the boiler. The purpose of the lockshield valve is to help regulate the heat output of the radiator itself, and to allow for a heating engineer to balance the radiators so that all the radiators in the heating system output heat at around the same rate. Once the lockshield valve has been set, via the balancing process, a plastic cap is placed on top of the valve to stop and 'shield' from any further adjustment. This 'locks' the valve in place. Once set, the lockshield valve rarely needs to be adjusted again unless there is a problem with the system or you need to adjust the flow of water. In short, the lockshield valve's job is to control the maximum and minimum amount of water that can travel through the radiator.

Shop at Mr Central Heating for our range of valves, including Lockshield Valves.

What is a Lockshield Valve?

We've already discussed the lockshield valve, but on the other side of the radiator you'll find another type of valve. This valve is adjustable by the user to control the radiator's heat output. This is different to the lockshield valve because it can be adjusted by the user as and when heat adjustment in the room is required. Generally, there are two different style radiator valves (that are adjustable by the user) available. These are manual valves and Thermostatic Radiator Valves (also known as TRVs).

Manual Valves

Manual valves are quite simple devices that you can think of like a tap in your home. You can adjust the heat of the radiator by simply turning manual radiator valves to the desired setting. However, achieving a desirable heat output can only be achieved through trial and error. These simple valves are low cost and look great.

Take a look at the manual valves that Mr Central Heating has in stock.

Thermostatic Radiator Valves

Thermostatic Radiator Valves are a different type of user-adjustable radiator valve that monitors the temperature of the radiator and automatically adjusts the room temperature to maintain a regular level. Once the TRV is set to the desired level, the valve automatically controls the heat output from the radiator. These thermostatic valves aren't that expensive to buy, but they are more expensive than manual valves. However, the cost outlay for the valves is offset by their energy efficiency. Because these valves can alter the heat output and control how hot the radiator gets in each individual room where a TRV is fitted, they are more efficient and therefore can help reduce your heating bills. TRV's in the UK are generally mounted vertically whereas the European style is to leave the TRV in a horizontal position.

Learn more about the thermostatic radiator valves (TRVs) that Mr Central Heating can supply.

Where and how the valves attach to the radiator may be different depending on the type of radiator you are connecting it to. Modern radiators tend to attach to the bottom of the radiator at opposite ends. This is known in the trade as a BBOE radiator (Both Bottom Opposite Ends). Other connection types are available too, although these tend to appear in older vintage radiators. TBOE stands for Top and Bottom Opposite Ends, and this as the name suggest means the valves attach at the top and bottom of the radiator at opposite ends. Whereas, TBSE means Top and Bottom Same ends, meaning that both pipes enter on one side of the radiator.

The only other considerations you might need to think about when it comes to valves is how the pipe attaches to the valve itself and in what direction the pipe will enter the valve. This tends to be more related to the way the pipes are set up in your own home. For instance, you can get straight radiator valves for when the pipework goes straight into the radiator in line horizontally. Straight valves are not the only type of valve available.

Straight Valves
Corner Valves
Angled Valves

Corner Valves are used when the pipework turns at a 90% angle into the radiator. Corner valves are used when the pipework comes from the wall and not the floor.

Angled valves are used for when pipework comes from vertically from the floor and needs to attach at an angle into the radiator. When buying a radiator valve you'll need to consider how your pipework is installed in the home to ensure you pick the right type of valve.

In the UK, the most common pipe diameter used in a central heating system is 15mm. So, you'll find that most valves accommodate this pipe size. This is not always the case, however especially in older homes so you may need to use different sized valves or adapters to convert the pipe size to a more traditional size. It's worth checking this prior to purchase to ensure you buy the right size connector on the valves.

It's worth noting that if you buy a new radiator they will not normally come with valves. This is because you need to pick the radiator valve to suit your own individual pipework. Often, people forget that both a lockshield valve, and a manual or TRV valve is required, for each new radiator. The good news is that Mr Central Heating provides valve sets that are perfect for your new radiator that includes both valves.

Understanding Different Radiator Types

Column Radiators

As the name suggests are constructed using metal columns and these radiators provide a traditional look but with modern efficiency. These radiators come in a range of different shapes, colours and sizes and provide excellent heat output. Individuals looking for more design-orientated look to their radiators tend to prefer this style of radiator. These radiators are available in both double and triple column designs.

Learn about the different types of column radiators that we stock at Mr Central Heating.

Compact Radiators

These are very common radiators and are fitted into a lot of homes in the UK. These radiators use fins to help transfer the heat to the room. These are smaller in size than column radiators but are also available in a lot of different shapes and sizes, along with falling into two distinct types, single panel and double panel radiators. As you might imagine a double panel radiator will provide more heat, at the expense of its size. Double panel radiators take up more room than a single panel radiator. These radiators are typically available in white only.

If you're interested in buying a compact radiator we have a large selection for you to pick from.

Flat Panel Radiators

These radiators have the lowest depth profile of all the radiators so are great at fitting in to a small or strange space. These radiators are available in a range of different sizes, such as vertical radiators and the more traditional horizontal design. We supply a range of 'wet' flat panel radiators, which means that they can be connected to a traditional central heating system just like a column radiator or compact radiator. A 'wet' radiator is one that uses hot water for heat. Often, when flat panel radiators are mentioned these can refer to electric powered radiators that are used in situations where rooms or entire buildings do not have a traditional wet central heating system installed. This can be quite common in flats, where space is at a premium.

Explore our wide range of flat panel radiators.

Towel Radiators

Just like a flat panel radiator, a towel radiator can be both 'wet' or powered by electricity. The reason these radiators are called towel radiators is because they are often found in bathrooms, and allow for the drying of towels. Most homes will likely have a towel radiator in the bathroom, if a radiator is installed there. Often radiators that fall into the towel rails category are made in stainless steel and are of chrome design.

You can find a wide range of towel radiators for your bathroom at Mr Central Heating.

Radiator Heat Output

One aspect that might not be immediately clear when choosing a radiator to buy (style aesthetics aside) is what heat output you will require for any given situation. Radiator heat output is measured in a metric called British Thermal Units (commonly written as BTU). A BTU is defined as the amount of energy it takes to raise one pound of water by one degree Fahrenheit. This is all very well, but not that useful for the average consumer. The good news is that to calculate what radiator BTU output you need you can use an online BTU Calculator such as the one featured on Mr Central Heating. All you need do is enter in some basic information and the tool will give you some guidelines as to the range of BTU you should use in your room. Too low and the room will never get hot enough, and too high the radiator will not operate efficiently, or it will be too hot. This tool will help you pick the right sized radiator for your needs.

Guide to Heating Controls

Apart from the boiler itself the other aspect to a central heating system that relates directly to the radiators is the heating controls and thermostat. Often, you'll find a thermostat fitted to your central heating system (often from the manufacturer Honeywell). This is used to control the overall temperature of the home. Generally (traditionally at least) the thermostat was in just one place in the home, someone near the centre.

The user can adjust the temperature control on the thermostat to alter the overall temperate in the home itself. Older thermostats use an analogue dial mechanism and are very simple to use. Later models may be digital and slightly more complex to operate; however, they are still quite straight forward.

You can browse our comprehensive range of heating controls at Mr Central Heating

It is also possible to install a room thermostat to control the temperature in an individual room. Thermostats control the heat output from the boiler itself and can switch the boiler on and off, whereas radiator valve control the heat output from the radiators. So, you can have a TRV fitted and a room thermostat together since they are complimentary.

The very latest technology available are smart thermostats such as those available from Nest. A smart thermostat is an intelligent device that can be connected to your phone or computer to help control your central heating. It can also integrate with other devices in your home to create a 'smart home'. Smart Thermostats are great because they can learn your lifestyle patterns, such as when you are regularly out of the house at work etc. They will control the central heating system automatically based on these learning patterns, which means they can save you a lot of money long term since they will switch off the heating when you are not around. If you want to save money on your heating bills and are interested in the very latest technology then smart thermostats are the way forward.