In this video I upgrade to a 3rd Generation Google Nest Thermostat to control my Viessmann Vitodens 050-W combi boiler. This will be a super in-depth video where I cover On/Off control, OpenTherm control, hardwiring the thermostat back to the Heat Link and share a couple of tips and tricks around mounting a Nest onto a standard back box and how to stop the Nest preheating a combi boiler. New Discount Codes - Get £50 off a new boiler with Heatable, use link (Affiliate) and enter voucher code CAMERON50 at the payment stage! Alternatively use the above link with voucher code NESTCAMERON to get a *free Nest Thermostat* included with your order worth £215! Buy on Amazon UK (Affiliate): - 3rd Generation Nest Thermostat: - Nest Thermostat Stand: - Preciva Ferrule Kit: Buy on Amazon US (Affiliate): - 3rd Generation Nest Thermostat: - Preciva Ferrule Kit: Chapters: 00:00 - Introduction 05:02 - Hardware Unboxing 13:07 - Heat Link Wiring Explanation 20:58 - Tour of Existing Installation 31:44 - Installing the Heat Link for On/Off Control 45:28 - Setting up the Nest Stand 48:11 - Initial Setup 51:06 - OpenTherm vs On/Off Control 56:55 - Wiring up the Heat Link for OpenTherm 01:02:49 - Configuring the Viessmann Vitodens 050-W to use OpenTherm 01:08:27 - Configuring the Nest Thermostat to use OpenTherm 01:12:46 - Demonstrating OpenTherm Modulation 01:15:13 - Hardwiring the Thermostat 01:24:52 - Trick to mount the Thermostat on a UK back box 01:33:12 - Hack to disable hot water preheat 01:38:27 - Conclusion *AFFILIATE LINKS NOTICE:* Product links under this video marked “(Affiliate)” are affiliate links where I may receive a small commission on qualifying sales. Affiliate programs that I am a member of include, _but are not limited to:_ Amazon Associates, eBay Partner Network and AliExpress Affiliates. As an Amazon Associate I earn from qualifying purchases. Purchasing through these affiliate links will not cost you any more money, however the commission earned significantly helps fund the production of videos on my channel.