SANITY CHECK - Replacing Drayton LP522 & Honeywell BDR91 with Nest

[uptoyou]

Hi all,

Hope someone can sanity check something for me quickly please?

I am in the process of replacing our existing wireless thermostat with a Nest.

As per the diagram below, can someone confirm a couple of things for me please:

1. Removing the BDR91 from the system, I just connect Yellow (Hot Water off? ((actually White, but used Yellow for visual clarity)), from the valve to the Grey (Hot Water on?), of the controller - the Yellow connection between the valve and programmer is NOT currently in place, this is what I am proposing.
2. There is no CH Off connection from the LP522, so I can just ignore taking this to the Heat Link

Since this was installed six years ago I haven't once looked at the programmer, just use the wireless thermostat for heating - no idea what timers are in place or how it is currently wired up to work.

Appreciate some feedback on if this looks OK or not, or if I have misinterpreted anything?

Thanks all!

 

[ianmcd]

I just connect Yellow (Hot Water off? ((actually White,

Doesnt have a HW off it is a room thermostat

You are way over thinking this, the heatlink simply replaces the LP552 and the existing room stat com and NO are linked, simple as that nothing else

 

[uptoyou]

Edit: made an error here

 

[uptoyou]

Thanks ianmcd, when it was installed I let the guy set it up and I've not looked at since that day, so I had no idea what was controlling what - but yes, of course, my current thermostat is just that, a room thermostat

My room stat is wireless via the BDR91, so as in the picture above (I believe BDR91 A = Common and B = N/O), disconnect all and just link White (Yellow in this diagram), wire from valve to Grey wire on HeatLink.

 

[ianmcd]

wire colours mean absolutely didly squat on a heating system, you only need to transpose the wires from the LP552 to the heatlink and join the two switching wires in the BDR nothing else

 

[uptoyou]

Cheers! LP522 wires moved to HeatLink, connected lives, and connected loose valve wire to loose HeatLink wire and all has fired up!