Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

Adding wifi relays to heating system

11 views
Skip to first unread message

Tim+

unread,
May 16, 2022, 1:15:35 PM5/16/22
to

If I wanted to add a couple of Wi-Fi controlled relays to my S Plan system,
would I be correct in thinking that I’d just need to wire the relays
across terminals 1 and 4 for CH and 1 and 6 for HW control?

https://flameport.com/electric/central_heating/S_plan_wiring_diagram.gif

Not fussed about having remote control of the thermostat, just the timing.

Tim

--
Please don't feed the trolls

Andy Burns

unread,
May 16, 2022, 1:42:02 PM5/16/22
to
I'd say 5 and 8, rather than 4 and 6

ARW

unread,
May 16, 2022, 2:00:11 PM5/16/22
to
Yes

But the programmer will override your relays unless you remove it but I
expect you knew that.

But I never use number 6. Number six is a free man.






Tim+

unread,
May 16, 2022, 2:02:45 PM5/16/22
to
Don’t think so. That would bypass both thermostats. I don’t want to adjust
the stats remotely but I do want the existing stats to work.

ARW

unread,
May 16, 2022, 2:03:59 PM5/16/22
to
That would override the stats. I assumed that he still wanted then to
work and just wanted wifi control of the programmer.

Tim+

unread,
May 16, 2022, 2:05:43 PM5/16/22
to
ARW <adamwa...@blueyonder.co.uk> wrote:
> On 16/05/2022 18:15, Tim+ wrote:
>>
>> If I wanted to add a couple of Wi-Fi controlled relays to my S Plan system,
>> would I be correct in thinking that I’d just need to wire the relays
>> across terminals 1 and 4 for CH and 1 and 6 for HW control?
>>
>> https://flameport.com/electric/central_heating/S_plan_wiring_diagram.gif
>>
>> Not fussed about having remote control of the thermostat, just the timing.
>>
>
> Yes
>
> But the programmer will override your relays unless you remove it but I
> expect you knew that.

Yep I appreciate that.


>
> But I never use number 6. Number six is a free man.

Not following you here… Can you expand?

Andy Burns

unread,
May 16, 2022, 2:39:47 PM5/16/22
to
I assumed he did want the wifi relays to override C/H and H/W independently?

Tim+

unread,
May 16, 2022, 2:50:09 PM5/16/22
to
But not the stats. Still want something to control the temperature of the
house and the HW.

ARW

unread,
May 16, 2022, 2:51:53 PM5/16/22
to
Please other posters tell me that I am not the only person on this
newsgroup to have run along Portmeirion beach shouting "I am not a
number I am a free man" whilst the wife phones the solicitor and asks
for divorce proceedings to start.

Best day of my life.

Tim+

unread,
May 16, 2022, 3:00:03 PM5/16/22
to
Doh! Shoulda got the reference! ;-)

Andy Burns

unread,
May 16, 2022, 3:16:17 PM5/16/22
to
Tim+ wrote:

> Andy Burns wrote:
>
>> I assumed he did want the wifi relays to override C/H and H/W independently?
>
> But not the stats. Still want something to control the temperature of the
> house and the HW.

OK sorry, I'm coming from the mindset of a wifi programmable stat, where the
timer may be on, and the room stat up to temperature, but I want a couple of
degree boost for an hour if I'm still not feeling warm enough.

Brian

unread,
May 16, 2022, 3:29:04 PM5/16/22
to
The way this is normally done, eg when a Hive system is installed, is to
removed the timer. On modern systems ( and that can mean several decades
old) the timer will probably be mounted on a Mark 14 back plate. This has a
footprint the same size as a single mains socket etc. There is a row of
terminals - as shown in the right hand group of your diagram- and the timer
/ programmer clips onto it.

Generally, to convert to a remote control system - such as Hive- you unclip
the programmer, clip on a box which has relays ( or equivalent) plus the
remote control interface. Sometimes minor adjustments are needed to the
existing wiring but the theory is, the Mark 14 plate provides a common
interface.

You should be able to adapt the idea.

Simply fit a relays wired to emulate the switching arrangement in the timer
part of your diagram, removing the existing programmer and connecting your
circuit to the corresponding points.

The coils of your relays will be powered by your control circuit - I assume
an Arduino or R Pi.



Tim+

unread,
May 16, 2022, 3:34:33 PM5/16/22
to
I’m just keen to ditch the existing programmer (or at least bypass it) as
it’s a pain to alter and not particularly flexible and I quite like the
idea of being able to fire up the system remotely.

Basic Shelly relays are very affordable.

Theo

unread,
May 16, 2022, 4:57:52 PM5/16/22
to
Brian <no...@lid.org> wrote:
> The way this is normally done, eg when a Hive system is installed, is to
> removed the timer. On modern systems ( and that can mean several decades
> old) the timer will probably be mounted on a Mark 14 back plate. This has a
> footprint the same size as a single mains socket etc. There is a row of
> terminals - as shown in the right hand group of your diagram- and the timer
> / programmer clips onto it.

There's a different way of doing things, which I've seen on some smart
thermostats, is you leave the programmer in place and set it to run the
heating 24/7. You then set the existing 'stat to a 'frost' position, but
wire the relay for the smart controls in parallel. That means the smart
controller can call for heat by closing the contacts, but the system is
still able to come in as a backup if the smart controller were completely
disabled. You can also override it by turning up the existing stat if you
want to.

This is much less work than a full programmer replacement and works even for
ancient wiring (ie potentially a DIY install, against Nest etc which are
often sold as professional installs).

Theo

Tim+

unread,
May 16, 2022, 5:08:44 PM5/16/22
to
Neat, but would mean adding another temperature sensor. That would cost
another £11.99 + postage! ;-)

critcher

unread,
May 17, 2022, 6:41:44 AM5/17/22
to
On 16/05/2022 18:15, Tim+ wrote:
>
is the thermostat too far away to stand up and turn it up?

Bob Eager

unread,
May 17, 2022, 6:46:55 AM5/17/22
to
Read carefully. It's not the thermostat he wants to control.

--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor
0 new messages