Heating system drainage and radiator removal

[HH @ 24]

I need to drain my central heating system to remove the radiators, which will (later in my renovation project) be replaced by new radiators in different locations. However, I don't know which pipe from the boiler I need to switch off to isolate the heating system and stop water from entering the system so I can drain and remove the radiators. Photos are of the pipework into the boiler. Can anyone tell which one belongs to the heating system? Thanks!

 

[a twig]

I’m not quite sure what you are asking - assuming it is a combi, the two grey taps are the filling loop and they are already shut off, so no new water would get into the system, is that what you meant?

 

[a twig]

Always helpful to look up the install manual for your make and model of boiler online to see what each pipe is if it’s not immediately obvious

 

[HH @ 24]

I’m not quite sure what you are asking - assuming it is a combi, the two grey taps are the filling loop and they are already shut off, so no new water would get into the system, is that what you meant?

H, thanks. Yes it is a combi boiler. So if I drain the central heating as the boiler is, no new water will enter the heating system until the two grey taps are turned? I was concerned that as I drained each radiator, more water would enter the system to replace the water draining away. But sounds like the system is "closed" to more water entering? Assume I don't need to worry about anything to do with gas when draining the heating system? (Complete novice at this, just trying to do the stripping out before the skilled tradespeople arrive to site and put back in!)

 

[Cubist]

Twigs right, re the 'fill loop', no new water will get into the system when its shut off.

One point to remember though is that you will still need to drain the water out of the rest of the c/h system before you can remove the radiators and existing pipe-work. You will need to connect a hose pipe to the drain valve (bottom left in your second pic) and the other end taken outside to a lower position. When you've done that, open the drain valve by turning the square tap on its top anti-clockwise - but be careful to not completely unscrew it from the body of the valve - and this will allow the c/h system to thoroughly drain. Completely draining the system may take a while and you need to be sure that all the radiator valves around the house are open to ensure they are empty too.

 

[HH @ 24]

Twigs right, re the 'fill loop', no new water will get into the system when its shut off.

One point to remember though is that you will still need to drain the water out of the rest of the c/h system before you can remove the radiators and existing pipe-work. You will need to connect a hose pipe to the drain valve (bottom left in your second pic) and the other end taken outside to a lower position. When you've done that, open the drain valve by turning the square tap on its top anti-clockwise - but be careful to not completely unscrew it from the body of the valve - and this will allow the c/h system to thoroughly drain. Completely draining the system may take a while and you need to be sure that all the radiator valves around the house are open to ensure they are empty too.

That's great, very helpful, thank you.