Changing a thermostatic radiator valve without draining down.

How to do the quick change (THE SNATCH). Freezer kit not required. No going up in the loft and plugging up the F and E tank with plugs. Save hours draining the whole system and refilling afterwards. Buy a decent quality Drayton valve here. https://amzn.to/3hY4s43 Visit Al`s plumbing shop for parts at http://amazon.co.uk/shop/dereton33 . Donate with a press of the SUPER THANKS button.