Replacing a rad with a condensing system

[meerekat]

I've recently upgraded my central heating to a condensing system and now embarking on a major decorating project - the main hallway, etc ... which will mean removing/replacing radiators.

Previously with the old gravity/pump system and jurassic boiler i could; bung the feed-pipes in the feeder tank, drain-off, and remove the rad no problemo.

Now, how do i create a vacuum on the system, as i've no longer a header tank, does the fact i seal off the feed at point of entry to the boiler mean there's already a vacuum?
Do i just simply drain-off and go?

* I've a Glowworm Ultracom 18SXI (mounted in the attic for convenience).

 

[petit_pablo]

Basically yes

 

[mysteryman]

No - close the central heating isolation valves on the boiler and select hot water only. Otherwise, close the valves at both ends of the rad to be removed. In each case, you will need to repressurise and vent afterwards.

It is not good for a heating system to keep draining and refilling it.

A classic application of the old adage: "If it ain't bust, don't fix it!"

 

[meerekat]

all was going well, managed to get the rad off without any major catastrophes.

However, when cutting the pipe to make way for the new rad (slightly different size) things got a little hairy. Upon cutting the bottom section of pipe the entire contents of what must of been the downstairs system came gushing out onto my hall floor (yes, i did swear).

Eventually the flow stopped with my frantically emptying ice cream tub after ice cream tub into the bucket (than god i was prepared, could of been so much worse).

The current situation is I still have a fairly constant drip of water stemming from the bottom pipe, will this eventually stop? ... or is there water getting into the system somehow??

For now, so i can sleep sound at night, i've plugged with 2 x compression end caps - both upper & lower pipes.

Any advise would be greatly appreciated.

* I did close the flow & return valves into the boiler.