Connecting Heatlink (Nest thermostat E) with Drayton wireless thermostat and Drayton SM1 timer

[marianlungu]

Hi,

I'm trying to connect the Heatlink to my current boiler thermostat and timer (photos below). The thermostat is a wireless Drayton WL2 and the timer is a Drayton SM1. The issue I'm having is identifying the NO wire as it comes from the Timer. So, basically the C wire is 1 on the panel and NO is 3, but 3 is coming from the timer. Any advice would be amazing.
Thanks and appreciate any help!!

 

[stem]

The timeswitch and thermostat each have a single on/off switch internally and are wired in series (via the screw connector) so that both have to be 'on' for the heating to work. If you ignore the N and L connections which are straight forward and are there to provide operating power. The actual switching circuit is simple. I'm going on memory of the timeswitch terminals here as you haven't shown the connections, but I think they will be the same as the thermostat. ie:

Therefore, the two switching wires will be the Grey and Black wires in the cable on the left. Be careful as they are not connected to the 240V supply at this end so the boiler maybe using 24v for control. This is not a problem for the Nest-e Heat link as it has a voltage free contact (NO & C) and is battery operated so doesn't need a 230V supply

 

[marianlungu]

Amazing, Thank you so much. Will try it later on this week !!

 

[stem]

Th easiest way would be to terminate & isolate the N&L safely in a couple of connectors, and then put the black and grey wires in the Nest-e 'C' and 'NO' terminals it doesn't matter which way around they go.

The cable to the timeswitch and the timeswitch itself can be removed.