Replacing Rad & Rad vavles on a pressurized (Combi fed)

[Kimba]

I am trying to fit a towel rail in replacement of a radiator in my bathroom. I have taken the old radiator off whilst decorating, and simply used the valves either side to isolate it. However I now which to change some of the pipework to chrome and install new valves. The problem is, the CH is fed from a Combi, and so to my knowledge this indicates a pressurized system, probabyl just under 1 bar.

My understanding is I need to switch off the boiler (controls etc) and close the incoming water supply, then take the values off, and allow any water under pressure to drain?

Fit new pipework and valves, the towl rail (with vents open), then allow water back into the system (not sure how, but assuming there is a top up tap/service valve near boiler?) until rad is full, then close rad, and allow pressure to climb up to 1 bar. Then bleed rad?

Power up and I am on a winning, or am I just about to break something! Help please

 

[breezer]

i am not a plumber or heating engineer, but i would say ALMOST right. you should drain the systm first

you should look for something like

but you may only (probably) have the hose connection piece. put a hose on this and turn the nut slowly. this will drain the whole system, then you can go ahead as you mention.

you should also add inhibitor when you refill.

oh and the water supply for the heating is already off (but turn main water supply off to be sure)

when refilling (search for "filling loop") you will need to bleed all rads

 

[Kimba]

Draining is no problem, but the "filling loop"? mmmm sounds interesting!


Can't switch off main water, that's another issue for next weekend. The stop cock is in a tiny cupboard with very little access and is completely limescaled open. It controls a feed from a HUGE tank on the roof (block of flats) and is on a black iron stil pipe (not gonna be able to freeze I don't think). Am currently pouring Limescale remover and WD40 on it at regular intervals

PS. Hello I am from London, and although actually a computer guy by day and trade, did Electrical and Electronic Engineering. Am a member of the IEE, etc and also like to think security/locks/alarms are my specilist area. Never scared to try my hand at something new, and plenty of DIY experience, but heating systems and boilers are still a bit of a grey area!

This site is brilliant!

 

[breezer]

ok, then dont orry about the incoming water for c/h as you said it is sealed system, and will be off anyway. but do turn electicity to boiler off.

 

[Kimba]

Okie doke, I will let you know how I get on - hopefully still from a nice warm flat.