1 rad not working

[Tosh]

Any suggestion sof what to start looking at trying will very appreciated.

A couple of months ago we moved into our Bungalow, it's had a small extension on the back of the kitchen with a Rad added t-ing off from the bedrrom rad (the last one on the circuit.) The 'extra' rad (in the extension) has never got hot but all the other 6 do. I've changed both valves on the rad that doesn;t work and the TRV on the rad it's Teed from as this was always cold.
I can;t be sure but I think at some point the Valves on the rad in the bedroom have been reversed as the return pipework is a hell of a lott hotter than the flow (with the TRV on). Seeing as the TRV is bi-directional I didn;t see it as a problem. The pipework leading away from the bedromm rad going to the extension rad gets cold within 2 or 3 feet of the beddroom rad so there's is only cool'ed water going to the extension rad. I've bled the system, there's no air, bled the pump in the ol Combi, fine.. Could it be that because it's an old combi (about 12 years old) that the pump isn't strong enough to feed the extra rad? Could it be they've t'eed off the wrong pipes in the bedroom (didn;t think that would matter though as only regular wheel head and lock shield on extension rad so water will flow through both either way).
Any suggestion greatly recieved.

Cheers Tosh

[uug197h]

i don't like T'ing off another rad they never get that hot if i was you i would drain the rads and replace the pipe under the floor or tap into the main feed and return to run both rads and not just T off its more work to get it right but it will be worth it (never cut corners it will always bite you in the ass)

[Tosh]

Hey Uug,
Thanks for the tip. Unfortunately being a Bungalow we are on solid concrete floors and guess where all our pipework is........Yep, under the concrete. I have no idea where the pipework runs, the only visible heating pipework is that of the extension Rad that has been 't'd. How far away from the boiler should I/could I tap into the main flow and return? There is at least 4 foot of pipework in the cupboard from the boiler at head height before it dissapears into the concrete abyss but if I can only tap into the horizontal run I'm screwed. I may end up just living with the rad not working and take it away completely. No point in having cold water running around a system.

Cheers mate.

[uug197h]

have you tried setting the flow on the rads have the one in the extention fully open and the other one set low (only open a 1/4) this may force the water to flow in to the rad in the extention

I have never put a rad in that close to a boiler the problem it water runs the easy way so it will flow past the T without going in the that pipe work to the new rad. the other option is to put under floor heating (electric) in the extrntion thay now make it for under tiles and laninate

[Tosh]

I like the idea of under floor heating, especially if it's electric and can go in without digging up the concrete floor.
Thanks Uug, will start looking into that idea.

[mcmoby69]

turn off all lockshield valves on rads rads except extension rad. does it get hot? if not there is a restriction/ blockage in the new pipework. if it does get hot start opening the other lockshields 1/4 turn at a time you should find a point where there is a happy medium between the rads. its called 'balancing' the system

[ProffesorPlumb]

Couldn't have said it better myself mcmoby

[Tosh]

I balanced the system out a while ago but still no joy.
Have gone right back to basics now, turning the heating on and finding out what pipes are what e.g flow and return and have now found out the Rad that is T'd from and the rad that wasn;t working have both had the TRV and lockshield installed round the wrong bloody way!!! Aaarrgghhh. Who'd buy a house from an old person, I ask ya!

So problem sorted anyway. Thank you all so much for your input and help, just shows seven brains are better than one.

Thanks guys.

Tosh