Draining & Refilling a sealed system

[jayzy1]

Hi all, sorry if this has been answered before but I tried to look back but couldn't find any posts. Anyway

I am a competant DIY'r & can manage general plumbing jobs myself.

I have a sealed CH system - Worcester Highflow 400 RSF, Basically I need to change a radiator in the downstairs cloackroom but is a different size to existing one. So I need to drain the system to change the piping & valves.

Can I just turn off the CH flow & return valves, attach a hosepipe to the draincock at the lowest point and rain away?

Is it just as simple to refill once completed. Can I just open these 2 valves and then refill the pipes& radiators up again?

I know I will have to open the vent valves on the radiators when draining & refilling.

Any advice & tips would be greatly appreciated as I need to do this asap.

Many thanks, Jim

 

[tincup]

Hi


Hire a pipe freezer from local builder merchant.
No refilling and loss of inhibiter just a top up.

Hope this helps

 

[gasmanuk]

Do what you said but turn your rad valves off to you may need to add more inhibitor too

 

[jayzy1]

Thanks, I intend to use
1. f****x central heating restorer
2. f****x superconcentrate central heating protector

(which I bought of fleabay for a tenner each) while I had the system drained, so wanted to drain it rather than freeze the pipes.

So what I said above should work then? Should I still keep the rad valves off on the other rads if I am going to use the above 2 items?

I intended to put the stuff into the new rad that I am going to install. Once the rad is all fixed up and I open the flow valves, I am just worried that I may damage the pump as there is bound to be some air in the system, from the pipes I have drained down. Would this be ok or should I be careful of something?

Thanks for the help & reassurance.