HEAT PUMP SPECIALISTS

What is weather compensation / Why are my radiators not as hot now that weather compensation has been fitted?

You may have had a new boiler fitted and you are wondering why the radiators are not as hot as they used to be, read on, we will explain why this is.

Weather compensation controls assist the heat source, whether that is a gas boiler, oil boiler, or heat pump and help them to work at their optimum temperature which can help lower running costs for home heating.

Weather compensation systems can reduce household fuel bills because they help the heating system to work more efficiently, ultimately reducing fuel usage.

Using smart technology, weather compensation systems will monitor both the internal and external temperatures and adjust the boiler’s operating temperatures automatically.

Instead of the boiler firing up or turning off and the boiler flow temperatures being say 72° when a house is too cold or too hot, weather compensation monitors the difference between the outdoor temperature and the indoor set point and will adjust the flow and return temperatures which can help reduce fluctuations in the boiler’s operation.

For example, on a cool autumn night, the temperature within a house may drop triggering the room thermostat to call for ‘heat on’. A signal will then be sent to the weather compensation control to turn the boiler on, at which point the control will use the outdoor temperature to calculate the water temperature required by the system. The control will then operate the boiler to allow the system to heat up to that specified temperature.

Meanwhile, on a cold winter night, the same steps and processes would take place. The control will use the outdoor temperature to calculate the system water temperature required in order to achieve the desired temperature within the home. As this will be higher, due to the colder weather, the boiler will be instructed to operate at maximum, modulating the heating system to the desired temperature. In each instance, the weather compensation instructs the boiler to operate in response to the actual conditions, working in maximum modulation mode when it is cold and tailoring the boiler’s operation (using less fuel) when temperatures are warmer.

Some Key Points

As far as gas boilers are concerned, the lower the flow temperature generally means you are using less gas.
If your flow and return temperature become nearing the same temperature, the boiler does not run in its condensing mode. Of all the installations we see this is nearly all of them do not run in condensing mode other than for the first 15 minutes while the system is heating up, meaning just because you have a condensing boiler doesn’t mean its condensing and saving you money. Nearly all of the time there are two reasons that cause this:
this is either the installer has not set the system up correctly,
or there is not sufficient technology in the system to automatically adjust the system temperature to maximise the efficiency in the system, which ultimately means you have an inefficient system.

Will be there be any noticeable differences in the heating system when using weather compensation?

Yes, the “touch” temperature, a.k.a. the flow temperature in the radiators may be lower than a system you have previously had.

This is good, as it proves that the weather compensation it is working!

What is clever, is that the flow temperature will adjust itself, up and down, as it needs to. When you are nearing the desired set point (on your room thermostat) the flow temperature may well reduce again.

When the outdoor temperature is mild, the flow temperature inside will reduce as the temperature difference (we call this Delta T) is small, relatively speaking and the system doesn’t need to work as hard to make this difference up, meaning if it reduces the flow temperature, or heats the property a little slower, the boiler will continue in its condensing mode and save you money.

This is all good for your gas/energy consumption and for the environment too.

Our #2 Final Tips

#1 Only concentrate on one thing: is the temperature set point, of say, 19°C for example being achieved in the room where the thermostat is? If the answer is yes, the system is working perfectly.

#2 When the system is running, close your eyes, forget the radiators, is it warm? If the answer is yes, there is no problem.

In summary, a weather compensation system can help a central heating system be more adaptable, achieving the appropriate heat output for the conditions and not simply just operating in an ‘on/off’ cycle. It will save you money too!