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New radiator cold. What to do first?

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Hi, i will do the bucket test this weekend. I have been reading posts and watching vids for 3 weeks now. Could someone out there possibly please point me in the right direction? Or at least give me an order of what to try first? Thanks in advance.

Scenario .
I took two old radiators out and capped the ends whilst I built a room in a room stud walls (soundproofing). I needed the radiator on the opposite wall so I ran the 15mm copper in the void up into the ceiling, around the ceiling and back down to the opposite wall (yorkshire fittings). Hung the new rad and fitted new trv and locksheild. It does not get hot. It gets full and I can bleed it with no gurgling of air, but no heat. I can watch the boiler water level drop as I bleed it. I'll list what I have done/ thoughts.
1) I do not know if I have the flow and return pipes correctly orientated. I did not check 1st = idiot! Would i still get some warmth? The old radiators used the get hot and I just extended pipework. Should I try switching them? Bodge it with push fits to test?
2) can a new trv valve be stuck? I have gently tapped it. Screwufix says they are bidirectional, so it shouldn't be the flow/ return issue?
3) if it is full of water cannot be an airlock?
4) I turned off all other rads and put the heating on. No joy. So not a balancing issue?
5) I bought another rad tail and was gonna do a youtube video where I remove bleed valve and drain with hose pipe from that outlet with valves closed. Is there a simpler fix? To remove airlock.

I know just enough to be dangerous!!! Any recommendations on what to do/ do first please. This room is costing an arm and...
Thanks for reading.
 
Thanks. So i should do the bucket test to push more water through? Fingers crossed for the weekend.
 
Not sure what the bucket test consists of but if I was trying to clear an high level air lock I would be trying to push water through the system as fast/forceful as possible. To this end I would disconnect the radiator and if possible run a discharge hosepipe from each of the valves to some external discharge area and then charge the system (assume its a combi boiler?) whilst alternative valves are opened thus forcing water and air out of the pipework.
 
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Thanks for the help mate. Sounds like i have a plan. I will try this weekend and if i fail I'll get a plumber in. This room has already cost an arm and shin bone. Thanks again.
 
If the new pipe work goes high into the loft and then descends to the new rad, then air vents on both pipes will be required at their highest point. Either manual vents or auto air vents should do the trick.
Your actions at the moment suggests only one of the pipes is clear.
Best of luck
 
I needed the radiator on the opposite wall so I ran the 15mm copper in the void up into the ceiling, around the ceiling and back down to the opposite wall (yorkshire fittings).

There is your airlock, in the ceiling. Running pipes up then back down, is a really bad idea - they will constantly airlock, because any air in the system will collect there. If no other way, you need to add an ABV, in each pipe, at the highest point.
 
Thanks for the replies! After reading up on abv's and aav's, there wasn't a workable solution as they might need maintenance and so i couldn't bury them behind the acoustic plasterboard.

So i ripped it all out, built another little stud wall, created a step and ran them between 'the new step'. At ground level with only a 150mm rise to the rad, the radiator got hot. Whoop Whoop. Thanks for the help.

I didn't really enjoy my first experience of plumbing. Hahaha.
 

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