Is this guy determined or what !!!!!
Luke , are you saying that the copper 8mm pipe is buried in concrete ? And if so ..is the plastic covering still on it because if not ( see my earlier post ) the concrete will have coroded the bare copper .
I'd suggest at this stage , ditch the original pipes and run two new ones ..in skirting trunking or boxing ..whatever gets them to the rad. Or move the rad to the new pipes .
I'd say the system was installed by someone , possibly wearing a stetson hat and sixgun , who tied his horse up outside while working at the house . I say that after looking at the state of the soldering and those cap offs at the manifold .
Most new houses are thrown together by speed merchants on a tight price and quality matters for nothing I'm afraid.
It seems to be buried in screed, I daren't pull up the hallway flooring to see if it covers the entire floor though. Plastic I assume covers it all the way through the ground, atleast it starts a good foot before going in, I assume it's covered end to end, but can't verify that at the rad end.
Now that you have isolated the blocked section of pipe have you retried the push-bike pump via an air tight connection and cranking it up really high? If something like 100psi+ wont shift it then I would think it is set solid. Great to hear you are making progress, it is much more fun here than at a plumbers forum honest!! Keep going Luke, you will fix it soon, plus you have a whole bunch of electricians rooting for you and hanging on your every post. When you do post that you have fixed it we will all go off for a celebration drink.
Doc H.
I went one step further, I borrowed an air compressor.
Jury rigged that to the rad end of the isolated 8mm blocked pipe, manifold end of pipe I clipped my drainage hose.
Air compressor on about 2/3rds (~150PSI), a sharp fizz, I hear the gargling of water down the drain pipe, air is getting through!!
Magnificent, I gave it a couple of minutes shooting air down, although I feared my makeshift connection to the pipe was failing me before I swapped the air compressor for some mains water pressure.
Re-checked my connections and gave it full mains pressure, a brief holdup, a tense moment, before the sound of gushing water (in the hose) and the rush of drain water gave me the satisfaction I've been waiting all week for.
The blockage had given way! Or at least in part. Huzzah!
I would put that down to the cleaner going in for a good 48hours and a large amount of air pressure, something that couldn't be achieved without the pipe being isolated, at that point I didn't care much for the pipe it was dead to me, I was just trying anything to clear it before I potentially had to dig it up or bypass it completely.
Here's where the fun starts.
Determined not to drain the system, I decided that my level of plumbing is now far past amateur, and that I could easily reconnect the existing pipe to rad and manifold (I still have the temporary line in between manifold and rad at this time). So I place my sauce pan, tap off the rad, disconnect the temporary flow line and end cap it before it gets everywhere... so far so good, a slight leak, a little bit of gaffa tape and leave it in the sauce pan. Right.
Now it's time to disconnect the manifold end from my temporary line and reconnect the existing (now cleared) 8mm pipe (using 8mm compression). Trying to be quick and hot swap, I just about manage it, only covered myself with the water, phew!
Only to hear "Luke stop, Luke STOP! STOP!!", "What?", "There's water everywhere!"... **** I quickly hot swap back to the temporary pipe and get to the living room.
I only left the valve off the 8mm pipe, connected to the rad and not the pipe! Idiot! Luckily it was largely caught by the plastic sheeting I'd put down a week ago and the water was largely clean, PHEW!
I refit the valve to the pipe and the rad then head back to the manifold, last step, get it swapped over and tightened up before I flood the hallway, again, fortunately I only manage to cover myself in water. I re-evaluated my skill in plumbing and shot myself down to Cowboy.
I tightened everything up, made sure everything was dry and not leaking and put the heating on.
I'm happy to report that the boiler is on full, the heating is on max and the house is baking hot - door is still off its hinges and it looks like the aftermath of the Somme but that's not important right now.
I drained half a rad and added a bottle of cleaner which I'll leave in for a good week, I'll flush it and probably add another bottle before eventually adding inhibitor and I'll fit the TRVs once I've got the cleaner out.
That's been one hell of an adventure. I've learned a lot and I wouldn't have managed it without your help!
ray 
