Swap programmer for timeswitch / wireless prog. thermostat

[TheKraken]

Given the wiring layout for the digistat as an example then :

What wires go where? I'm assuming that the Neutral comes from the 240v mains (from the vertical connector), and the the new connection on 5 is a permanent Live.

That leaves me with the wire from pin 2 which I assume is switched live. I'm thinking it goes to 'call for heat', but are there other connections to make inside the digistat receiver?

The honeywell similarly :

Makes it look like the A terminal is simply connected to permanent live, and the switched live (marked BR) goes to B?

Please excuse my ignorance, but I'm trying to understand it, as well as just do it.

 

[D_Hailsham]

Given the wiring layout for the digistat as an example then :

I'm assuming that the Neutral comes from the 240v mains (from the vertical connector)

Correct,

the new connection on 5 is a permanent Live.

Correct

That leaves me with the wire from pin 2 which I assume is switched live. I'm thinking it goes to 'call for heat', but are there other connections to make inside the digistat receiver?

Oh dear, this is where you go wrong

You have to put a link between the L terminal and Common. If you don't there will be no voltage on terminal 2 or 3.

You connect terminal 3 to terminal 2 of the wiring centre

The honeywell similarly :
Makes it look like the A terminal is simply connected to permanent live,

Better to connect L to a permanent live (5 on wiring centre) then link L to A.

and the switched live (marked BR) goes to B?

Bit confused by BR and B
Terminal B goes to 2 on the wiring centre

 

[TheKraken]

Bit confused by BR and B

Sorry, they're the naming conventions on the honeywell 'zone valve' diagram, BR I assume being the convential white cable on a mid-valve.

 

[D_Hailsham]

Bit confused by BR and B

Sorry, they're the naming conventions on the honeywell 'zone valve' diagram, BR I assume being the convential white cable on a mid-valve.

Now you are confusing me even more

You do have one three-port mid position valve not two two-port valves, don't you? That is a Y-plan not an S plan?

 

[TheKraken]

Yes, a three-port mid position valve.

I think I've been confused myself by the options in the honeywell manual, choosing the one that mentioned a valve, rather than the others (two of which ~ combi / cooling ~ I certainly don't have).

Am I to assume that the wiring schematic I'm looking at is the burner (direct control) option then, for the honeywell?

 

[D_Hailsham]

Yes, a three-port mid position valve.

I think I've been confused myself by the options in the honeywell manual, choosing the one that mentioned a valve, rather than the others (two of which ~ combi / cooling ~ I certainly don't have).

Am I to assume that the wiring schematic I'm looking at is the burner (direct control) option then, for the honeywell?

Yes

If you have a three-port valve then you have a Y-plan (Honeywell) aka BiFlow (Drayton).

Here is the Y-plan piping layout

and here is a typical Y-plan wiring layout. It achieves the same results as the Biflow, but is easier to understand.

However, as you are using two separate timers, one for the HW and a combined timer/thermostat for the CH, the wiring has to be modified. So Honeywell have produced an Application Guide.

There is an error in the wiring diagram The connection from the ST6100 HW Off to the L641a terminal 2, shown in the schematic, has been missed off the wiring diagram.

I hope I am not confusing you If you follow the wiring shown in the modified pic above you will find everything works; ebven if you don't understand how

The junc box needs to be re-wired as the cyl stat off and hw off from programmer are both using earth coded wires which is a big no no.

Heatingman is quite right to bring this to your attention. What he is saying is that the green and yellow earth wires are not being used for earthing purposes but to carry 240v. This could be very dangerous to someone who did not realise this. Unfortunately it is found fairly frequently. The correct cable to use in this case is a three core (brown, blue and another e.g.black) or a three core plus earth.

 

[TheKraken]

That honeywell pdf is very useful, if only they did one for drayton wiring centres!

There is an error in the wiring diagram The connection from the ST6100 HW Off to the L641a terminal 2, shown in the schematic, has been missed off the wiring diagram.

Just to try and prove my understanding, if I read the ST6100 manual correctly, that would mean a missing wire between connection 2 on the ST6100 (timer off) to connector 7 on the wiring centre connector block (where the L641a terminal 2 connects), in the wiring diagram.

In any case, given your excellent diagram earlier, I now know that if I follow that, and then connect :

wiring box -------------- digistat receiver ----- or ----- honeywell receiver

240v neutral ---------------- N terminal --------------------- N terminal
pin 5 (live) ------------------- L terminal --------------------- L terminal
pin 2 (switched live) ------- 3 terminal --------------------- B terminal

and then link 1 and L for the digistat, or A and L for the honeywell.

 

[D_Hailsham]

Just to try and prove my understanding, if I read the ST6100 manual correctly, that would mean a missing wire between connection 2 on the ST6100 (timer off) to connector 7 on the wiring centre connector block (where the L641a terminal 2 connects), in the wiring diagram.

Correct.
I was thinking about 2-channel timers when I referred to the HW Off terminal. As the ST6100 is only single channel there is only one Off terminal!
Do you already have the ST6100? If not, as I said in my earlier posting, you could always use your the HW channel of your existing two channel timer and disconnect the CH side completely. Although, when I upgraded I went against my own advice and purchased a single channel timer (on Ebay) for the HW, which I installed in the airing cupboard, where the pump, HW cylinder, MV and wiring centre are, so it was out of sight.

In any case, given your excellent diagram earlier, I now know that if I follow that, and then connect :

wiring box -------------- digistat receiver ----- or ----- honeywell receiver

240v neutral ---------------- N terminal --------------------- N terminal
pin 5 (live) ------------------- L terminal --------------------- L terminal
pin 2 (switched live) ------- 3 terminal --------------------- B terminal

and then link 1 and L for the digistat, or A and L for the honeywell.

Correct

 

[TheKraken]

I've ordered the Honeywell Wireless Stat now, so I just have to wait for it to arrive. I'll probably start off using the existing LP241 for the hot water timings, and maybe upgrade if I find I want different timings on different days (the wife's often complaining we run out of water on the weekend).

Thanks for all your help D (and Heatingman for getting me started).

 

[TheKraken]

Just finished wiring the new thermostat in, and it all works fine. Took about 40 minutes in all.

Reused the redundant heating wire in the programmer to replace the earth-wired HW/off, so that one is at least wired correctly now.

Thanks again.