Thank you for your mail.
I am sorry to hear that you are having issues with your radiator
Could you please answer the following questions for me:
1) Has your radiator been installed professionally?
2) Where do you have your return valve left or right, top or bottom?
3) Has your heating system been hydraulically rebalanced after installation?
4) Have your bled the radiator of any air after installation?
5) What is the input water temperature leaving your heating system?
Once I have the answers to these questions, I shall be able ascertain what the problem is with your radiator.
The hot water enters the radiator when the valve is opened and circulates around the radiator to generate the heat.