Draining upstairs central htg rads only in a vented system Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[Dougie]

I want to drain the upper floor radiators in my house so as to replace and resite a bathroom radiator. The heating is a fully vented system 24 years old with F&E tank system. There are no drain off valves on the rads. There is a drain however on a 15mm pipe that enters the boiler next to what appears to be the hot water feed to the storage tank. I assume this 15mm pipe is the direct cold feed from the F&E tank?

If I open this valve and lead away the water through a hose connection having first interrupted and secured the F&E supply I assume this will drain down all the central heating system if I open the all rad air vents ? I don't need to drain all the rads surely so should I secure all the rads valves except for the one rad to be changed? Is my logic correct and how do I know when I have drained down just the top half of the house heating?

Am I risking damage to the 24 years old other radiators by draining down ? The pipes and rads have not been touched before this time.

Any help gratefully received for DIY first project!
Dougie

[johnb]

hi dougie simply drain all the system and add inhibitor when refilling use a good make ie,sentinel fernox etc there is no advantage in part draining however on a 24 year old system it may be time to consider new rads especialy if black sludge is found , all the best john