Help Please with a Nest Install and Honeywell

[rolors]

Hi,

I am a newbie here so please be gentle

I have just purchased nest and installation, but unfortunately the planned install is not as soon as I had hoped for and I need to go overseas for a some time.

I have studied the installation and I think I know what I am doing , but have a few questions that hopefully an expert can help with here.

The system is an S plan using Honeywell components as shown below.

This is what I intend to do - please let me know if I have something fundamentally wrong.

1 - Turn the power off!!

1-My intention is to take the power for the heat link from on old disused socket (with 3 amp fuse) that used to power the shower pump ( which has been removed).

2- Connection T1 & T2 - Disconnect the 3 cables from the terminal block ( 2,4 & 5) that connect to the thermostat (T6360)- then connect cables that where removed from 2 and 4 into the T1 & T2.? Tape over the spare cable.

3- Call for heat - Disconnect cable 4 from the terminal block ( feed from terminal 3 from the existing controller-ST699) and connect to Call for heat, terminal 3 on the Heat Link?

4- I have no idea for the Common connection, Do I simply install a jumper from the Live to terminal 2 on the Heat Link??
( I assume that I don't need to connect anything back to the terminal cable block no 4 ?)

5 - Remove the old stat and replace with the Nest controller, ensuring the cabling is as 2 above.?

6 - Turn the power back on & hope for the best??


If I have something wrong, please could you let me know

All help appreciated.

Thanks

Colin

Nest

• rolors
• 2 Nov 2014
• 1

Nest

• rolors
• 2 Nov 2014
• 1

Nest

• rolors
• 2 Nov 2014
• 1

Nest

• rolors
• 2 Nov 2014
• 1

Nest

• rolors
• 2 Nov 2014
• 1

Nest

• rolors
• 2 Nov 2014
• 1

Honeywell

• rolors
• 2 Nov 2014
• 1

Honeywell

• rolors
• 2 Nov 2014
• 1

 

[picasso]

On my way out so I haven't got time to go through all of your post but its a no no to supply any part of your central heating installation from two separate supplies so supply the heat link from the same supply as the rest of your heating.

 

[rolors]

Hi Picasso,

Wow, thanks for the swift response.

Seems like what I thought was the easiest part was a big NO, No.

I assume I just take the power from 1 & 2 on the terminal strip then?

Thanks for you help

 

[jackthom]

As picasso says, take the heatlink supply from terminals 1&2 in the wiring centre.

Then it will certainly be OK to jumper the live supply across to the relay common in the heatlink box.


(Otherwise with a seperate supply there's the danger that even with the CH turned OFF the call for heat could still burn someones fingers while working on the wiring centre.)

 

[steve158]

Edited and deleted reply.

 

[Dean744PiN5]

And don't take it for granted that your wiring centre follows the s-plan diagram, check it through first if you haven't already,

and then at the room stat temporarily join the 2 wires going into the nest together, then go to wiring centre and take what you think are those 2 wires and with a multimeter check for continuity across those 2 wires, go back down disconnect the 2 joined wires then check the continuity is now broken.

This will ensure you haven't mixed up any other wires and accidently send 240v to nest which WILL blow the unit up.