Vailant Thermocompact with Nest

[AndyThilo]

Hi

I’ve inherited this old boiler with our new house. It’s a Thermocompact 620e System Boiler with separate hot water tank.

I’m confused about the wiring as there’s only 1 wire to the boilers control connections as shown below.

Upstairs is the cylinder with 2 motorised valves, connection box and Honeywell timer. Thermostat is in the hall downstairs.

Any ideas how I get this connected up? Anyone know how the boiler controls both heating and hot water from one control wire?

Thanks

Andy

EE0C3453-BDA4-4830-8CFB-F17E0F0B7593

• AndyThilo
• 10 Sep 2020

 

[picasso]

Your nest controls the zone valves and the zone valves control the boiler, google nest with s plan and there are plenty of wiring diagrams available.