Nest Thermostat on Main Combi 30 HE boiler

[Swarfega]

Hi guys,

Complete newbie with boilers so bare with me.

Looking for some help in deciding if I can install a Nest thermostat myself and save £90 in the process.

I currently have a wireless thermostat (Baxi 5117391) controlling my Main Combi 30 HE boiler.
From looking at the wiring diagram on page 47 you can see the "Optional Timers" connecting to block A3 on the PCB. Would I just need to disconnect the two black cables from the timer and put them in the Heat Link (port 2 and 3 in the image), then also move Brown to Live and Blue to Neutral on the Heat Link?

Manual for the current Baxi thermostat.

 

[Swarfega]

Nobody?

 

[flameport]

Yes, you are just replacing one thermostat/timer with another one.

 

[Swarfega]

OK thanks.
Since there are two black cables would it matter which port I put them in on the heat link (ports 2 and 3)?

 

[flameport]

No, makes no difference.

The heat link/ thermostat / controller or whatever else is just a switch. When heat is required, the two black wires are connected together inside the controller.

 

[Swarfega]

Thanks Flameport. Appreciate the help.
Have a good new year!

 

[SilentDancer]

If you already have a room thermostat and programmer you will save very litlle and may even spend more as the heating will be adjusted and used more to increase comfort. Where did you see the save £90 figure?

 

[Swarfega]

My current programmer is hardly used. Were always having to flick the heating on and off manually as we come and go. I've come home many a time to a hot house as the wife has left it on when she went out. The house is either hot or cold so figured the Nest would work better for us.

Wednesdays OAP's get 10% off. £250 is installed. £179.99 with no install. £161 with the 10% off