DIY Doctor UK DIY Forums

Is it OK to drain down a Central Heating system using the drain cock on the Boiler? The DIY Guides show draincocks on radiators, which I don't have.

Hi,

Yes you can use this drain down point.

What are you draining down for, if you are working on downstairs rads, just be careful, as unless your boiler is below the lowest rad you may find that there will still be water in the downstairs rads.

Hope this helps.

Rico

drain needs to be at lowest point on system. So unless your boiler is on the floor then no. Water wont drain upwards now will it? :? You should have a drain somewhere on the ground floor, if you have an old system then you may no, in which case you should get a plumber to come and drain down and install a draincock

Depending on what system you have Indirect or Combi, you could bung the feed & overflow at the F&E tank in loft, this will create airlock to enable you to remove a downstairs rad valve and replace it with drain off rad valve, then do you drain down from there.

Rico

As the post above said, strictly speaking you need to drain from the lowest point fo the system. However, it depends on what you're draining for as to how much of a drain you need.

We also don't have any drain points on our system (despite it only being a few years old - I guess the installer saw a way to shave off a pound or two...) so I generally drain by undoing one of the connections to one of the downstairs radiators; this is only about 6-8 inches above the lowest point, so is "drained enough" for everything I need.

I'd also recommend opening the bleed valves in the upstairs radiators so that the water can flow out freely (otherwise it dribbles away against a vacuum). Whatever you do, have towels, buckets, ... a plenty if you can't get a connection to run a pipe outside.

I'm a diy-er by the way, not a pro - so, treat my advice (or flame me!) accordingly.

this is the method i use when coming across systems that have no drain off:-


http://www.awin1.com/pclick.php?p=18830 ... 071&m=1228

clamp this to your lowest point, connect a hose and drain down.

when your finished, cut that little section out and replace with a yorkshire tee with a drain off while its drained down


saves alot of time

what happens if you didnt have 15mm pipes eg 10mm then would this self cutting tap still work? if not what would you do then ?? cheers