Wiring of Honeywell ST6100C controller to Baxi 105e

[robbierazz]

Hi There,

I have just purchased the above controller and wondered whether anyone could advise on the connections to the boiler, or provide a wiring diagram showing how they interconnect?

I am an electrical/electronics engineer so am competent to carry out the wiring myself, but just not 100% sure of the connections, and it is always best to ask if not 100% sure.

Also, can I feed the 240V supply to the controller via the fused side of the terminal block on the PCB within the Baxi 105e? The supply to the boiler is via a switched fused (3A) spur.

Many thanks in advance for your help.

Robert.

 

[baxpoti]

http://www.partsarena.com/baxi/
Catalog » Baxi » Boiler » Combi » Combi 105 HE (GC No. 4707518) » Installation Instructions » Combi 105HE iss 03
Page 23[/list]

 

[baxpoti]

http://www.partsarena.com/baxi/
Catalog » Baxi » Boiler » Combi » Combi 105 HE (GC No. 4707518) » Installation Instructions » Combi 105HE iss 03
Page 23

 

[robbierazz]

Thanks for the info Baxpoti.

The wiring diagram doesn't show whether or not the external controller is powered from the fused side of the mains input terminals on the boiler. Would it be ok to connect it this way, so that the controller would be effectively fused via the pcb fuse?

Also, I now gather I need just 5 connections from the boiler pcb to external controller, as follows.

L/N/E, a common connection and a switched connection (timer on)

Is this correct?

Thanks,
Rob.

 

[robbierazz]

Hi again,

I forgot to mention in my previous post, but the honeywell controller instructions mention about linking terminal 1 with the L terminal if normal mains voltage switching is required, i.e. not potential free mains switching. Could you please clarify which option I'd need to use to connect to the Baxi 105e?

Thanks,
Rob.

 

[baxpoti]

Yes
linking terminal 1 with the L terminal if normal mains voltage switching is required (there is a 230v potential difference).

Terminal 1 from boiler is 230v out providing boiler selector switch is in c/h mode
Bring sw/live back from controller onto terminal 2.

Your controller and wiring will then be protected by the fused spur and the onboard fuse.

 

[robbierazz]

Hi again Baxipoti,

Many thanks for your help on this, it's most appreciated.

Anyway, just to clarify then, here are the connections that are needed as I understand them.

1. Connect L and N from Terminal block on Boiler PCB to L/N terminals on ST6100 controller to provide the supply.

2. Link L and terminal 1 on ST6100 controller.

I am a bit confused still as to how to connect between Terminal's 1 and 2 on the boiler and Terminals 1,2,3 and 4 on the ST6100C. Terminal 2 on controller is 'timed output off' and terminal 4 is 'timed output on', so do I need to connect to both of these terminals, and if so how?

Sorry to be a pain, I just want to make sure I understand the connections before wiring it up.

Thanks,
Rob.

 

[baxpoti]

1. Connect L and N from Terminal block on Boiler PCB to L/N terminals on ST6100 controller to provide the supply.

Yes you can pick these up from the spur (To save on cables into boiler bring a 5 core 0.50/0,75mm fom spur and do all your other connections in the back/beside the spur[use a dual box terminal strip and blank cover plate])

2. Link L and terminal 1 on ST6100 controller.

Yes, this saves bringing two lives to the controller

I am a bit confused still as to how to connect between Terminal's 1 and 2 on the boiler and Terminals 1,2,3 and 4 on the ST6100C. Terminal 2 on controller is 'timed output off' and terminal 4 is 'timed output on', so do I need to connect to both of these terminals, and if so how?

Boiler 1 to programmer terminal 1
Boiler 2 to programmer terminal 4
Programmer terminal 2 is not used
Programmer terminal 3 is not even shown on my ST6100!

Double check your Honeywell wiring diagram to confirm

 

[robbierazz]

Ok, you say that terminal 1 from boiler provides 240V to the controller terminal 1 when selector switch is set to CH. If this is the case, could you please explain why I 'also' need to connect the controller L and 1 terminals together?

Is this correct, or have I got the wrong end of the stick somewhere along the way?!

 

[namsag]

There is no need to link the live on the clock back plate to terminal 1 on backplate this is to provide power for internal switching in the clock for use with a standard boiler.. On baxi 105e boilers this power is supplied from the terminal strip connection 1 to conection 1 on back plate that then goes through the clocks internal switchin an out on terminal 4 back to boiler connection 2 to complete the circuit....


But you have not mentioned the roomstat do you have one and how is that wired in at present also what clock is currently fitted

 

[robbierazz]

Hi namsag,

Thanks for that, it makes perfect sense now. That's how I thought it should be connected and couldn't understand why terminal 1 should be connected to the L terminal, if 240V is already being provided to terminal 1 on the controller via terminal 1 on the Boiler.

Anyway, I don't currently have a room stat, instead all of the radiators have thermostatic valves fitted. Not ideal I guess, so I will probably invest in a room thermostat at some point and fit in the lounge.

In the meantime I will fit the ST6100C now that I know the connections required. Also, is it necessary to bring an earth connection from the boiler to the earth 'parking' terminal on the ST6100 controller back plate?

 

[robbierazz]

Sorry, forgot to mention last time, but an integral mechanical timer is currently fitted.

 

[namsag]

pretty certain 6100 is double insulated and instructions will confirm but if you look at it the way it is wired the earth post is not connected to anything and boiler etc is earthed through fused spur

 

[robbierazz]

Hi namsag,

Thanks, I will check to see if controller is double insulated. I think you are right now thinking about it, but will double check tonight.

Many thanks for your help, most appreciated.

Rob.

 

[robbierazz]

Hi There,

I've just wired the controller up to the boiler, with connections as follows.

Boiler Terminal 1 to ST6100 terminal 1

Boiler Terminal 2 to ST6100 terminal 4

L and N on Boiler to L and N on ST6100.

Switched unit on and display flashes and enables me to set the correct time. However, when the ST6100 switches on, i.e at the preset time or when switched to continuous, the CH does not come on.

Could it be to do with the fact that I haven't linked terminal L and 1 on the ST6100 together?

Please help, as I currently have no heating. I can hear the controller switch when set to continuous.

Thanks,
Robert.