Pipes under the boiler

[Andrei Guinea]

Good afternoon guys. Just a quick question.
Under my boiler there are few pipes and by mistake I've turn that switch (see pic) on/off. It's says "C" on a pipe but I don't know what that means. Have I done something bad to the boiler doing that?

And one more question please. I would like to drain the whole system in order to change one of the radiators. I don't know where is the water switch under the boiler so I'm planning to switch off the boiler, shut the entire water in my house, drain the entire system from the downstairs radiator, change the radiator, turn on the water back and after turn on the boiler. Is that right? Do I have to do something else?
Thank you very much in advance.

 

[ShaunCorbs]

That one you’ve marked is one side of the filling loop

There’ll be another valve like that somewhere also a flexi to refill the system

You can drain the rads as the system won’t fill / keep running as it’s a sealed system hence the filling loop

 

[SimonG]

Looks like the valve for a filling loop.

As for the drain down bit going to need a bit more information. What sort of boiler is it.

 

[Andrei Guinea]

The boiler is a greenstar 25i. The thing that I'm using to fill the boiler is that blue thing under the boiler. Can I use that tap that is before the black thing to turn of the water to the boiler and after to follow that steps that I said before? See pictures for details please.
I'm sorry for using "thing" to call that stuff but I don't know the name of them.

 

[ShaunCorbs]

The valve before the black one is the cold inlet to your boiler eg the turn the hot water off

 

[Andrei Guinea]

Understood. So in order to drain the heating system to change the radiator, switching off the whole water system from the street will be alright?

 

[ShaunCorbs]

Understood. So in order to drain the heating system to change the radiator, switching off the whole water system from the street will be alright?

No need to turn the water off as it won’t auto fill

Just turn the electric off to the boiler

Drain
Do your works
Then refill via your normal method eg the blue lever

 

[Andrei Guinea]

No need to turn the water off as it won’t auto fill

Just turn the electric off to the boiler

Drain
Do your works
Then refill via your normal method eg the blue lever

That's even better that I thought. I will start the work now and I will come back with a reply. Hopefully everything will go right. Thank you very much for your time.

 

[centralheatking]

Wow Andrei you are keen, be carefull changing your radiator, you will need to drain the dirty water out of the whole system including opening all the radiator bleed valves to get all the water out. Then fit your new radiator and then do the process in reverse. I would also
put replacement inhibitor chemicals into the system AFTER you have tested it watertight.
ask as many questions as you need ....centralheatking

 

[TonyC]

"C" means cold as in cold water pipe.