new rads & drain CH?

[rabu]

Hi, have come on here to see if someone can just help me out with couple of things, firstly we have 2 rads both singles and fed from 15mm or 1/2" with belmont valves (old ones) the 2 rads both are manky looking and rusty on bottom edge also water is black inside so think its time they were changed. However whats the best way to shut of water and drain CH, just fitted new mains stoptap so that now closes 100% unlike the old one, so would this be the best way to turn of? at main. Also can only find one drain cock at base of cylinder but looks old, corroded.. wouldnt really trust it, one rad was replaced ages ago by a plumber who i think draind from the rad had, a BG orange hose running from rad to outside, would this have been on the WH or LS valve? Also the boiler is a old baxi back boiler with (i think) primatic cylinder, as its old and we only have 1 cold tank in loft. Would the cylinder need filling slowly? and does anything need to be done to the tank up in the loft? since the plumber kept going up to it also kept tuning boiler on and off. Sorry for all the questions, I have done some plumbing, new mains tap, new bathroom...just never changed a radiator. Thanks for any help or advise.

 

[Pope John 2]

Your system is a mess, get it ripped out get a good G Safe fitter to put a mean n' green one in and live happy not stressfully

 

[garygas]

The tank in the loft will have a ball balve. Tie the valve up so it doesnt let water in.
Or there should be a gate valve from the cylinder to turn off
Or just turn the stopcock at the mains water off and connect a hose to a radiator which has a drain off on a rad valve and open.
Think your system could do with flushing too.

 

[rabu]

dont know about flushing, maby, but all the other rads are in good condition and the water is fairly clean in them, just the 2 i want to change are rusty and black water coming out. otherwise its all working well, little noisy sometimes like trapped air but never had any problems with it. think thats what the plumber who did the rad befour did, turn of under sink at mains then drain through rad valve, non of our valves have a drain off on them though. there is a gate valve on cylinder but thats also never been touched so now that seized it wont move and if it does will probs leak or stick shut. my main problem was about they cylinder being primatic about filling it again. draining through rad would this only drain the CH water part of the cylinder?