Why is newly installed radiator in porch not heating up ?

[Sappy]

Hi
Having recently had a porch built I came to realise a radiator would be of benefit thus have installed a myson decor with trv.
Due to the floor being concrete and having to ensure the pipework was within a sleeve and insulated etc I took the advice of the plumbers merchant and included isolation valves in case of future issues should they occur?!
On connecting the radiator and opening the isolation valves I heard water go through the radiator, it was immediately warm so trv was set and radiator bled etc thus all was well, so I thought!
I have now come to realise a few days later that the radiator is cold?!! I have no idea why? Any one help?
I haven't yet fiddled other than to bleed the radiators and no air apparent.
Any suggestions much appreciated as although tend to be reasonably competent at DIY I don't claim to understand all the workings of such things thus when things don't go to plan I find myself stuck!
Thanks in advance
Lisa

 

[noseall]

Once you have done the obvious i.e. opened the bleed valve on the rad etc, try turning all the other rads in the house off and run the heating.

If it is still not working then it may be a sticking TRV or summat else.....?

 

[Hugh Jaleak]

Assuming rest of the system is working ok, and the offending rad heats up with the others turned off then you may need to balance the system to ensure the porch rad gets its share of the flow.

Balancing instructions can be found in the FAQ's in the Plumbing Forum.