Urgent - how to drain combi boiler system

[aargh]

Help - can anyone advise how to drain our combi boiler heating system? My bloke got carried away with the floor sander today and holed the radiator pipe, & we got some epoxy but there's a bit too much pressure for it to seal, & can only find instructions for draining a traditional heating system with tanks. Not sure how it works for combi's and don't want to knacker the new heating! If it helps the boiler's a Vaillant Ecomax condensing combi... Also will we need to re-do the inhibitor afterwards & how? Thanks for your help before things get too soggy!

 

[oilman]

Go to the boiler and find the pipe that goes outside from a valve with a red top. Twist the red top, and you will hear the water going down the pipe.

Post reply if any problems.

 

[ChrisR]

look for one of

those on the pipes somewhere

 

[oilman]

look for one of....... those on the pipes somewhere

Reference won't work.

 

[aargh]

Thank you, that was quick! We found the red doofer and emptied it out, now presumably just need to drain the radiator too and get mending. Will we need to put new rust inhibitor stuff in before filling it up again?

(no-longer-quite-so) aargh

 

[oilman]

Try turning off all of the radiators, both valves on each. This will mean you dont have to replace the water in the rads.
If the pipe with the problem is upstairs, drain enough to get the water level down far enough, but no further. You can buy a crartridge of rust inhibitor if you empty the system, and it can be squirted in the rad bleed valve. If you shut off the rads and don't empty the system completely, you won't need more inhibitor.

 

[ChrisR]

Was trying to show a pic of drain cock - there should be one or more somewhere.

If you have a towel rail, or rads with a bung at the top which you can take out, you can add the cheaper, liquid, inhibitor through that.

 

[aargh]

Thanks for the help both of you! The water's nearly stopped coming out now & have got a temporary patch on the hole. So going to head to bed now and then go to the plumbing shop in the morning to get something to fix it properly. Any suggestions for best way to patch the hole are most welcome, but otherwise will ask in the shop. Good night all!

 

[oilman]

You should cut the pipe off below the hole and replace the pipe. Use one of these or similar

or one of these

Then connect a short piece of pipe to it using one of these

You will need an olive for the end that connects to the radiator valve as well.

 

[ChrisR]

ok ok stop showing off I know you can make it work. I've been trying to show one of these
http://www.screwfix.com/sfd/i/cat/33/3349_l.jpg

or is it like this:

 

[aargh]

Actually think we've managed to fix it a different way. As the hole was almost floor-level we would've had to rip up all the newly-sanded floor to put in a new bit of pipe; but as it was just a small hole Pete got some of that stuff you put in the radiator to seal it from the inside. Made a right mess putting it in, but hey - it seems to have worked to my surprise! No more water coming out - and the floor is now varnished and looking good after all that. Thanks for all your tips (and snazzy pictures)! Will try not to have any more disasters...