Designer radiator problem

[johnny2007]

Hi everyone, I have a new horizontal designer radiator (boss asked for it) which is not getting warm at the centre bottom.
It's like hot water enters on the right, rises to the top 3 bars and then drops down to the left leaving a cold semicircle.
Plumber has been and said the diffuser in the radiator creates this problem and there's nothing we can do.
The previous standard radiator worked perfectly.
Plumber tried all tricks including closing all other radiators and bleeding this one, but nothing.
He reckons that either the internal diffuser is same as many others and makes things worse.
We disconnected the radiator to check for sludge, but it's new and the water was clean as we always had the inhibitor topped up.
The diffuser, if it's there, is not removable.
So it's working but not as well as all the others.
Is it possible that there's air trapped in the middle of the radiator?
Thanks

 

[ianmcd]

the diffuser must go on the flow it wont work on the return

 

[johnny2007]

It's on the flow.
The plumber even tried swapping pipes around but it's the same.
So he's put it back on the flow.

 

[ianmcd]

can you post pics of the rad and the valve setup ?

 

[johnny2007]

can you post pics of the rad and the valve setup ?

Tomorrow.
Boss sleeping now.
Thank you.

 

[johnny2007]

Sorry for the delay, here is the picture.
Flow on the right, return on the left
The bottom 3 bars are stone cold, the next 2 lukewarm and the rest hot.
Bled the radiators and balanced.
Radiator is new and instructions didn't mention any direction.
As said we tried swapping flow and return and also removing the thermostatic valve.
Pin moves freely.
What do you think?

 

[johnny2007]

Also, there's no sludge in the system.
Radiator in ensuite works perfectly.
Tried to close all other radiators and bleed the bad one but didn't make any difference.
When we closed all other radiators, that one got hot all over.

 

[ianmcd]

you havent added a pic ?

 

[johnny2007]

Sorry, here they are

 

[ianmcd]

I have never seen a horizontal designer rad like that, all the ones I have seen have the bleed and blanking plug are on the top of the rad not on the side, are you sure that is not actually a vertical rad ?

 

[johnny2007]

Definitely sold as horizontal radiator.
Otherwise the valves would come out from top and bottom, me thinks.

 

[ianmcd]

Do you know what make and model the rad is ?

 

[johnny2007]

Unfortunately I can't find the receipt.
It's one of those long term projects, we bought it in summer and only got around to fit it now.
I can't remember where i bought it from and looked through my emails without success.

 

[terryplumb]

Also, there's no sludge in the system.
Radiator in ensuite works perfectly.
Tried to close all other radiators and bleed the bad one but didn't make any difference.
When we closed all other radiators, that one got hot all over.

Do you mean the problem rad got hot all over or the bathroom rad did?

 

[johnny2007]

The problem radiator got hot all over when we closed all the others