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  • LHS Plumbing Services

The Ultimate Guide to Central Heating and Hot Water Controls

Updated: Apr 6, 2020

Heating engineer adjusting controls on boiler

All across the country people struggle to keep up with their energy bills, and that’s because the central heating and hot water system drains a substantial amount of it. As technology improves in the industry, though, so does the efficiency of your heating system. Subsequently, it allows you to retain control and reduce your energy costs. But, the problem is, most people have no idea how to utilize the controls effectively.

By managing your boiler, you can not only ensure your home remains as comfortable as possible, but also boost its efficiency. The best part is, you don’t even need to do any manual adjusting if you program it correctly, because your system will kick in automatically when you want to, using the least amount of energy.

Now, considering how beneficial it is to know how to use your central heating and hot water controls, we’ve put together this awesome guide to teach you. The controls we’ve included derive from the recommendations found within the Government’s Building Regulations Compliance Guide for Boilers and Radiators. So, if yours differ, you will need to seek guidance from your system’s manufacturer.

Without further ado, let’s get into it…


The programmer is essentially the brain of the system, because it instructs the boiler when to come on and when to turn off. Those instructions will come from you, though; by using the programmer, you can select what time of the day it turns on and when it turns off. Additionally, you can also customize the regime for weekdays and weekends, meaning it’ll perform differently during the week as opposed to the weekend.

Moreover, if you have a hot water cylinder integrated into your system, you’ll have even more control. That’s because you can set a time for your hot water as well. The huge advantage of being able to do this is that you can ensure no energy is being wasted when no-one is home or it’s not needed.

So, the key to using the programmer is to always bear your lifestyle in mind. If you and your husband work 9-5 and your children are at school, you can set the system to be turned off throughout the whole day and activate automatically when everyone is home on the evening. But, most systems come equipped with a “boost” function, which is basically an emergency supply button.

In a nutshell, if you schedule your boiler to turn on at 7pm, but you return home at 6pm and you’re absolutely freezing, you can use the “boost” function. It will provide you with a short supply of heating and hot water, and then automatically switch off at the end of the period.

Various heating controls in a domestic home.

Room Thermostat:

What differentiates a programmer from a room thermostat is that a programmer is a “master switch” which tells the boiler to turn on or off, whereas the thermostat controls the temperature. But, the thermostat can also instruct the boiler to turn on. Why? Because if you set your internal temperature to 20-degrees via the thermostat and it dips below that, it will tell the heating to fire up to increase the temperature around your home.

The best idea is to set a temperature that you are comfortable with, and then leave it at that setting. Regardless of season or weather outside, you shouldn’t need to adjust the thermostat, because the boiler will do all of the hard work to reach the desired internal temperature. But, if you want to reduce your energy bills, it’s advisable that you set it at a lower temperature.

The majority of people are okay with it being around 18-degrees, which is perfect as it won’t tap into as much energy. One thing we desperately urge you not to do is bump up the thermostat level in an effort to warm your house up quicker. Not only will it not work, but it will send your energy bills sky-rocketing, especially if you forget to turn it back down.

Oh, and a quick tip – be aware of external influences; if a window is open in a room, it may affect the thermostat and the heating could turn on when it’s not needed.

Programmable Room Thermostat:

In most homes, you’ll find a programmer and you’ll find a room thermostat. They’re both awesome features and you’ll save a lot of money on your energy bills by utilizing them effectively. But, some central heating and hot water systems have a juggernaut control, which is known as the programmable room thermostat. It removes the need for two controls, as it’s a programmer and room thermostat combined into one.

On its small display, you’ll see a time and temperature metrics, and it empowers your boiler to be a lot more streamlined. You see, it’ll tell your boiler when to turn on and when to turn off, and it’ll react to the set temperature to control the boiler almost instantly. If you’ve hooked up your cylinder thermostat to it as well, it will also allow hot water to run freely during the “on” period.

It’s very similar to operate as the programmer and room thermostat, but it’s just shown on one display. A massive advantage of this control is that you can set different temperatures for different times of the day. For instance, if it’s usually freezing in the mornings, you could set a higher temperature, and then have it automatically drop for later on in the day.

Thermostatic Radiator Valves:

A superb strategy to help with the energy expenditure in your home is to have thermostatic radiator valves (TRVs) fitted in each room. By doing that, you can set individual temperatures for each room that includes a TRV and remain in control of them. It coincides with a room thermostat, as it guarantees that the heat emitted from the radiators reflects the set temperature on the thermostat.

Let us explain… if you have 20-degrees set on your thermostat but the radiator is bumping it up to 22-degrees, the TRV will sense that and reduce the radiator heat. Like the other controls, TRVs do not worry about the temperature outside, so they’ll perform in the exact same way whether it’s summer or winter. That’s because the priority is hitting an internal temperature that everyone is comfortable with.

Usually, TRVs will consist of a number scale ranging from 1-6; with rooms that never get used, you could keep the setting on 1 to keep the heat from the radiator at the very minimum. Moving on, TRVs do not have any impact on the boiler, so they’ll never tell the boiler to turn off when it’s too hot. But, they can save you money by limiting the amount of energy that the heating system needs to provide.

Cylinder Thermostat:

The cylinder thermostat is all about your hot water, as it allows you to effectively manage the temperature of the hot water running through the system. All you need to do is set a desired temperature on the display; it’ll monitor the water inside the cylinder and then tell the boiler to turn off when the set temperature has been reached.

Of course, if your heating is still on then the boiler won’t turn off, but the cylinder thermostat will shut the valve so the boiler stops providing hot water. It’s just like a continuous cycle… you’ll use hot water, the cylinder will be reimbursed with cold water and the thermostat will tell the boiler to activate so the fresh water reaches the set temperature.

But, if you’ve used the programmer to schedule a “no hot water” period, the boiler will not heat the water regardless of what the thermostat says. If you’re looking to decrease your energy bills, then a sweet spot is around 60-degrees; it’s hot enough to eliminate any harmful bacteria while low enough to stop your bills from going through the roof. Be aware, though, because the water coming through the tap will still be scalding at that level.

There you have it – the ultimate guide to heating and hot water controls. By absorbing all of the above information, you should now have the necessary knowledge to fine-tune your heating system and make your energy bills plummet. Although it may seem complicated, managing your heating system is actually very straightforward these days.

Like we’ve already mentioned, if you have any controls that aren’t listed, consult with your system manufacturer and ask them for some information.

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