@Msull Hi there, check out this article on this topic and see if this helps. Thank you.

Thanks Adam, unfortunately it doesn’t work, tried running it for over 30 mins! 

Hi @Msull,

Each side of your Dyson fan heater’s loop amplifier contains a PTC element. As you’ve confirmed that one side remains continually cool after an extended period of use, it sounds like one of the elements in your machine might not be working.

Your regional Dyson Support team will need to take some further details to see what options are available to resolve this. If a repair or a replacement is needed, they’ll also be able to confirm whether you’re still covered under your Dyson warranty. You can find the correct contact details on our Guides and manuals page.