Joe: Should I turn off my combi boiler (central heating, radiators) for the summer? And leave only the water heating part on?

Combi boiler

Yes! Turning off the heating part of your combi boiler during summer 

is a great way to save energy and money on heating costs, 

especially when you don't need it. 

Just be sure to leave the hot water setting on if you still need hot water for showers and other purposes.

Keep in mind that if you turn off your heating for an extended period, 

it's a good idea to turn it on for a short time every few weeks 

to keep the system running smoothly and avoid any issues when you need to turn it back on in the fall.

Radiators

As for the radiators, you can turn them off individually by turning the thermostatic radiator valves (TRVs) to their lowest setting or completely off. 

This will prevent any hot water from flowing into the radiators, reducing your energy usage and keeping your home cooler during the summer months.

However, it's essential to leave at least one radiator on to act as a "bypass" and prevent any damage to your heating system. 

It's generally recommended to leave one radiator on when using your combi boiler's heating function, even during the summer months. 

This is known as the "bypass" radiator, typically located close to the boiler, 

which helps prevent damage to your heating system by allowing water to circulate and avoid overheating or pressure buildup.

However, when you turn off the heating part of the boiler during the summer, leaving a radiator on is not necessary, 

as no hot water will be circulating. 

Therefore, you can safely turn off all radiators without concern for damage to your heating system.