Draining down Central heating.

[dazzlerpalmer]

I am in the process of fitting all new rads in my house and I am adding a new
radiator in the utility room.

Rather than branch off existing rads I cut the flow and return (22mm) pipes.
I then drained the system and tried to solder the new joints.
Unfortunately they leaked. I could not get all the water from the system.
I opened up all the draincocks on the downstairs pipes and left the system for
three hours. The mains feed to the header tank was switched.
Admittedly the pipes were only dribbling but enough to stop the solder.
I got over the problem with compressions although I was wondering why both ends of
each pipes would not stop leaking water?

Did I need to draining the coil down?

Any suggestions please?

 

[Nige F]

So everything is ok and working ..........Then the reason is a Trade Secret

 

[Paul Barker]

If it's ground floor cut one pipe under the floor and let it all go, blow down one end of it water comes out of other end, may take 1/2 hour and lots of blowing to see of every bit. Cheats way is now solder your two joints you couldn't do before which are probably above this level and then do this one joint up with pushfit (only if you cut it with a pipe slice) or compression if you used a junior hacksaw. You can solder the final joint but only after you're blue in the face blowing every drop of water out.

If in an upstairs flat can still be done but get a shallow receptacle to collect the water and keep bailing.

I had to do this some 4 or 5 times in a row on a job I took over from a kid, many of his sodlered joints hadn't penetrated. I expect more will leak in coming months. Householder will definately suffer in the long run for going for the cheapest quote in the first place.

 

[Bahco]

I've used bread in the pipe to be soldered which has held the water back a couple of times, (tip from an old plumber) which has done the trick with no problems.

 

[chrishutt]

Did you open the radiator air vents when you drained down? If not, it wold explain why it kept dribbling water.