Problems with an antique radiator

[eftech]

I have recently fitted an antique Victorian radiator in place of an existing modern single radiator in my central heating system. The problem is, it doesn't heat up. It came from a reputable dealer and was tested and fitted with new bushes before I got it. I can bleed the radiator, and do get warm water flowing through after a while, but it doesn't seem to find its way through to the return valve, although that is clear. The
The existing pipework is 8mm, and the radiator had a 1/2 inch BSP inlet and outlet. I have checked the pipework above and below the floor and it is not kinked or leaking.
The boiler (a Vokera combi) is fine and was recently serviced.
I have tried balancing the radiator system (there are another three radiators, of which this is the last), but cannot get it to heat up. Could it be that the 8mm pipework is not big enough to fill the radiator?

 

[EliteHeat]

I'll probably be shot down in flames by Nige F, but try turning all of the other radiators off - it's probably just airlocked. When the heat starts going through, open up the other rads.

 

[Nige F]

not this time, Kimosabe.....the poster mentioned pipework sizes and "modern system".....just an old rad on it .......tho I reckon 8mm is alright for automotive petrol lines, that`s about its only use

 

[bengasman]

what do you call a modern system? judging by the 8mm pipe, it is from the previous century

 

[Slugbabydotcom]

Try this:-

Drain and take the rad off.
Check that there is a clear way through the rad by shining a torch through it, running water through it, sticking a bit of left over 8mm pipe through it whatever........

Turn the valve on at the filling loop. If your water pressure is over 3 bar expect some to blow out of the pressure relief valve or you could let a cold tap run with moderate speed at a sink/bath to lower the pressure a bit.

Run a bucket or two full of water from each rad valve. You could even stick a hosepipe on it.

No water coming out means you have a blockage.

If its only piddling out slowly you are expecting to much of the 8mm pipe or you could have a partial blockage between there and the point where you connected to the existing system.

Turn the filling loop valve off, reconnect and bleed radiator.

Having ruled out a partial blockage after this excercise and perhaps a bit more balancing your rad will either work OR common sense will have told you that the 8mm ain't big enough.

How much 8mm pipe have you used?

Is it true that 8mm pipe was invented by 2 scotsmen fighting over a length of 15mm pipe?