New Radiator issue cold from bottom

[lollypop909]

Hi, i am wondering if I can get some advice please? I have moved into a new house a few months back. We had a single panel radiator which wasn't giving much heat so i decided to change it to a type 22 radiator. I bought a new 1600x500 kudox radiator with new trv and lockshield but the new radiator is cold from bottom and hot from top.

I have tried bleeding it and balancing it but no luck. I turned all the radiators off except the new one and turned the heating on. The boiler made loud grining noise and I could also hear lot of noise coming out the radiator. But the bottom of radiator did get a bit warm.

So about 20 mins later when i opened the bathroom towel rail, the boiler started behaving normally. So now i am very much confused and thinking whether the new radiator faulty? Or there is a bloackage in the pipe for that specific radiator? All other radiators in the house are burning hot from top till bottom.

What can I do now? Any advice please is welcome. Thanks

Oh and the trv and ther other valve is fully open.

 

[Gasmk1]

have you turned both valves on

 

[lollypop909]

have you turned both valves on

Yes both valves are fully open anticlock wise

 

[999]

Did you replace both valves with new valves or use the existing vavles?
Sounds like there is a blockage in the pipe or a sticking thermostatic valve

 

[SimonG]

Was the old rad the same length?
What size pipework is the radiator Fed by?
Copper or plastic?

 

[lollypop909]

I replaced both valves with new ones.

The old radiator was an old 2400x400 single panel. I replaced with 1800x500 type 22. Copper pipe work. I am planning to put fernox cleaner in the system for a week to see if there is anything clogged up and advice on putting a magnafilter after the clean up. Should i put one and which one?

Thanks