Turning the boiler off the summer

Deedoodee

We dropped the rads for decorating a month ago and one radiator was broken in the process. Now we’re running into snags with getting plasterers so by the time the plasterings done (if no other issues) the rads won’t go back for another 6-8weeks. Is it ok for the boiler and central heating system to be off for this long? Boiler is about 5 years old.  

FreeBear

My boiler has been off since April.

Just make sure you add some inhibitor and pressurise the system when you are ready to fire it up again.

Deedoodee

FreeBear said:

My boiler has been off since April.

Just make sure you add some inhibitor and pressurise the system when you are ready to fire it up again.

Thanks. My friend said nothings been running through her radiators for months as it’s summer but she does have it on for hot water and didn’t know if that made a difference. 

FreeBear

Ah... If you have a combi boiler, probably not a good idea to run it for hot water. Depending on the design, you could damage the CH heat exchanger.

Deedoodee

FreeBear said:

Ah... If you have a combi boiler, probably not a good idea to run it for hot water. Depending on the design, you could damage the CH heat exchanger.

So we’ve not been getting hot water (not living there at the moment). Only using cold water for tasks when we’re there. She doesn’t turn her boiler off because she’s using it for hot water. Is it not a good idea to turn a combi boiler off? 

bris

Why would running the hot water on a combi boiler damage the heat exchanger? Thats its whole purpose to heat water.

The radiators can be isolated which it sounds like they ar so the hot water will still work.

If would be best to drain the system though if its off for up to 8 weeks. On a combi the diverter valve keeps the hot water seperate from the radiators so you can still keep the hot water working.

Bendy_House

Provided the actual CH pipework hasn't been drained down, and on a pressurised system (like all combis?) it can't have been or else it would simply refuse to fire up, then running the DHW side should be fine. Any residual heat in the exchanger when you turn off the hot tap would be driven off by the boiler's by-pass, if all the rads were shut off/removed.

And the boiler would warn you by rumbling if it wasn't happy 😊

With a conventional, heat-only, boiler, heating your hot cylinder will keep exercising the pump and valve, and the only item I can think of at very remote risk of seizing would be the CH zone valve, if separate.

They rarely stick, and a lump of wood is quite persuasive if they do. Or, simply move the manual lever... The former is more satisfying. 

Ddd, I would not be concerned at all. Any unlikely issues as a result would be very simple to resolve, almost certainly at no cost.

Bendy_House

Can you recall if the water drained from these rads looked clear? And we're any of them hosed through after removal? 

Just thinking this is a good time to ensure your system is as clean as possible before they are replaced.

As FB says, adding inhibitor on refill is essential. And, if not already fitted, give serious thought to adding a magnetic filter on the return pipe to the boiler.

Deedoodee

Bendy_House said:

Can you recall if the water drained from these rads looked clear? And we're any of them hosed through after removal? 

Just thinking this is a good time to ensure your system is as clean as possible before they are replaced.

As FB says, adding inhibitor on refill is essential. And, if not already fitted, give serious thought to adding a magnetic filter on the return pipe to the boiler.

Don’t know how the water looked. We just left the plumber to it. No hosing through after removal. I think he just removed them and left. 

Bendy_House

And the plumber will be reinstalling them? In which case, consider asking about the filter at the same time - about £100 - if you don't have one (I think all boilers replaced in the past 5-odd years WILL, by default).

At the existing rads in good order? Will you be replacing any, other than the damaged one? If so, also consider future-proofing your whole system by 'over-sizing' them, so that they can output the same heat, but with cooler water. Just about every future energy -efficient heating system we will all ultimately be obliged to use will be working at lower temps, so larger rads will be needed to provide the same heating output.

The damaged rad to be replaced - is that in a main living area? If so, please consider over-sizing. Eg, extra panel/fins/convectors, or even literally 'bigger'!

daveyjp

Many modern boilers have a summer setting which turns off the heating.

However, it also puts the boiler in a mode where the boiler fires occasionally in heating mode so the diverter valve remains operational.