How to turn down the flow temperature of your boiler
The flow temperature is the temperature of the water that comes out from your boiler to your central heating pipes and radiators. Changing the flow temperature will not affect the temperature of the water that goes to your hot taps.
If you have a condensing combination (combi) boiler you can adjust the flow temperature. If your combi boiler is an old standard efficiency (non-condensing) boiler or you have a hot water cylinder in your heating system (with a system boiler or heat only boiler) then you should not reduce the flow temperature. If you turn down the temperature with a hot water cylinder, there is a risk of harmful legionella bacteria growing.
It is the heating knob on the front of your boiler that you need to adjust. If you are unsure which that is, please refer to your user instructions.
- Turn the knob right up so the screen shows the maximum flow temperature.
- Slowly turn the knob down, so that the screen on the front of your boiler reads 55 degrees. At this temperature your boiler will be at its most efficient, saving you the most money.
Importantly, if you lower your temperature, you still need to keep your home warm in cold weather, so by turning the temperature up a few degrees at a time, you will find the right flow temperature to suit your needs.
During very cold weather, you may need to turn the flow temperature back up a few degrees to ensure your home is warm enough. Turn it up a few degrees at a time, until you are comfortable. Then, when the cold weather has passed, you can turn the flow temperature back down to 55 degrees.