What is the summer setting on a combi boiler?
The summer setting on a combi boiler can be your best friend when the summer time hits.
It’s a bill saver when the weather starts to get warmer, and it quickly becomes one of the best ways to make sure your house isn’t generating even more heat when it’s already 30°C outside.
This guide covers what summer settings on a combi boiler are, how to activate them, our best tips for using them and why summer settings are a far better choice than shutting down your boiler completely.
What is the summer setting and why should you use it?
Most combi boilers have a designated summer setting, usually called “Summer mode”. The “hot water only” option (if you have that instead of summer mode) is identical in function.
Switching on summer mode disables your central heating, so no energy will be supplied to the radiators, but your hot water remains active when needed.
How to turn summer mode on
- Find the dial
Look at the front control panel of your boiler for either a sun symbol, a tap symbol, or a mode switch marked “Hot Water Only”. - Set the dial
Turn the central heating dial (marked with a radiator symbol) as low as it can go, or switch it off altogether. - Check that it’s working
Run a hot water tap. This will cause the boiler to operate and heat the water; however, the radiators will remain cold.
Why you shouldn’t turn your boiler off
If you don’t need to use the central heating because it’s already warm and you want to save money rather than keep the boiler idling, why not just switch it off instead of keeping it on at all?
It’s a common question that makes sense on the face of it, yet there are actually several reasons why turning off the boiler is a worse choice than using summer mode.
No hot water
Switching your boiler off means you’ve got no hot water, so when you need a shower or to use the hot tap, you’ll still have to switch the boiler on and wait for it to heat up again.
This is much more faff than simply switching over to hot water mode.
The risk of the boiler seizing
Your boiler’s internal components need to remain active to avoid seizing up and running into issues later down the line when you need to use the central heating. The pump and diverter valve are two important parts of the boiler that can seize up if left inactive.
It becomes a problem in the making once you move away from the summer months and into the cold autumn and winter months.
The summer setting will ensure that your boiler stays functional.
Stagnant water leading to corrosion
By turning your boiler off completely, you risk the water corroding the pipes and damaging your pipework and the boiler itself.
What are the best practices for your boiler during summer?
Once you’ve switched to summer mode, there are a few extra tweaks you can make to keep your boiler running efficiently and your bills as low as possible.
Turn the preheat off
When working normally, combi boilers preheat water and keep it ready for use when you turn your taps on. This constantly uses energy, even when you’re not using any hot water.
In summer, you’re unlikely to need instant hot water as often, so turning the preheat off can save you a huge amount on your energy bills without impacting your usual day-to-day in the summer months.
Water temperature
Set your hot water temperature to between 50°C and 55°C. This is hot enough for comfortable showers and washing up, but not so high that you’re wasting energy heating water beyond what you’ll actually use.
Keep in mind that this is only applicable for combi boilers. Boilers with hot water cylinders like system and conventional boilers work differently. Stored hot water shouldn’t be set lower than 65°C, as anything lower allows harmful bacteria like Legionella to grow.
The ideal system/water pressure
The pressure in your boiler needs to be between 1 and 1.5 bar on the pressure gauge. Anything lower than 1 bar can cause your boiler to fail or throw an error message.
Anything higher than 2 bars may require you to bleed your radiators. That is why it is important to check your pressure gauge from time to time.
Read more: Beat the bills! Expert tips to reduce energy costs
How to keep your boiler in top condition
Summer mode is handy, but it’s not exactly just turn-on-and-forget. There are a few extra steps and precautions you can take to ensure your boiler responds well to summer mode.
Turn the system on (at least) weekly
Use your central heating for at least 10–15 minutes once a week. This might seem counterintuitive, but it’s essential because this way you make sure that the pump, diverter valve, and other components inside the system work properly.
Get your boiler serviced in summer
Summer is the ideal time to book your annual boiler service. Engineers are far less busy than in the autumn and winter rush, so you’ll get more availability and shorter wait times.
Then, if any issues are found with your boiler that might affect use and need repairing, you’ll have the summer months to deal with it, so you’re prepped for autumn and winter.
Is summer mode worth it?
Summer mode is one of those small changes that saves you money and protects your boiler at the same time.
It takes 30 seconds to switch on, keeps your hot water running, and avoids the risks of turning everything off completely. If you’re unsure how to find the setting on your specific model, check your boiler manual or get in touch with a qualified engineer
