Room stat changeover contacts

Sam Gangee

Sam Gangee

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I'm in the trade but not in the business of installing central heating systems. I'm {58} a qualified electronics engineer.

The plumber who came to install my oil-fired central heating got totally flummoxed because I'd specified a room stat with timer. The one he brought (electronic by Siemens) has L1 L2 and pump and also T1 T2 for "remote signal". L1/L2 are the NO/NC connections - I assume the NC isn't used (what's it for?)

What the heck is the T1/T2 "remote signal" connection pair for?
 
NC can be used to tell the heating system that the call for heat is "satisfied". Or it can be used for cooling apps (like air conditioning).

No idea on the others but it would really help if you can say what model of room stat you have. There's hundreds.

Once we have that we could look at the instructions. But maybe you have those too? If you're a qualified electronics engineer it can't be that hard :wink:
 
Guys, thanks very much for taking the time to reply. Of course I'm kicking myself for not making a note of the model number before the plumber took it away to "consult the experts in Athens". It looks similar to the model you linked to. I'll have to wait until the plumber returns "met'avrio" (a vague term meaning "some time after tomorrow").

The system is currently working with a conventional room "stat" as shown here:
http://www.glodark.com/stat/

It's a temporary rig so excuse the cavaliar use of G-Y for anything but earth! The rest of the wiring is very nicely done. What I will need to know is how to connect the timer/stat but, unless the labelling is standardised, I guess you can't tell me without knowing the model number.

Edit: My timer/stat wiring diagram is identical to that shown in the above-linked REV17 data sheet. I see that T1-T2 is for connecting a remote control switch or relay so that I can, for example, "phone home" and set it to a predetermined temperature to override the program. I won't use that.

Basically, all I'm asking is how do I substitute a REV17 for the temporary stat that's connected at present?

I can see that Brown will go to "L". :)

Looks like Grey will go to "L1"?

G-Y (aagh!) goes to "N"?
 
No!

Green/yellow is earth. It must not be anything else.
it goes to earth at the boiler end and to the handy earth tag at the thermostat end.
 
I think you misunderstood the question. G-Y is already connected to the temporary stat. I just want to know where the wires should go on the new one. I'll argue about the colours with the plumber when it's all working. But, knowing the culture here, he'll merely shrug and say "δεν πειραζι".

BTW I don't know why my post has been moved here. I'm in Greece!
In Greece, ALL colours are live until proved otherwise (by getting the Armenian helper to lick his fingers and touch them).
 
No one will advise you to use the G/Y for anything other than earth on a uk forum.
looking at your pic, you have enough wires and relevant colours to do the job properly to conform to Uk if desired.
Greece standards may be different, and not sure what response you will get if moved to the other forum.
Maybe they can move it back if you alert the mods.

A clearer pic of the old stat wiring diagram may help, or the model number.
Is it
http://www.totaline.com.tr/pdf/SiemensOEMKatalog/RAA30_Oda_Termostatı_anahtarlı.pdf
 
I think that no-one wants to guess what the blue, brown, grey, black and G/Y wires are connected to at the other (boiler) end, especially when the earth is already being misused as a neutral.

A data sheet for the RAA30 is easy to find on the internet, and I doubt that you actually need to connect to more than L and Y1 (NO) on that, any other connections are probably just indicators or somesuch.

On the new one you also just need to do the same.

However it is up to you, using your skills as an electronic engineer, to determine what the wires in your wall are connected to at the other end, and most definately to remedy the use of the earth wire for anything but earth.

To re-iterate, only two of the wire are probably really necessay, and they are just connected so that the thermostat is acting as an on/off switch.

(I now expect a tirade from a certain other forum member, for trying to be helpful.)

EDIT: I shouldn't take so long to reply!
 
Sam Gangee said:
I can see that Brown will go to "L". :)

Looks like Grey will go to "L1"?
Click to expand...
Your halfway there
You need to find the other end of them wires and sort out a BLUE neutral AND G/Y earth that end and connect your new the same.
Your new stat Needs a neutral and an earth present.
 
You may be right

I was going by this.

Sam Gangee said:
I can see that Brown will go to "L". :)

Looks like Grey will go to "L1"?

G-Y (aagh!) goes to "N"?
Click to expand...

I also assumed it needed a neutral for the display, maybe the battery does that.
Good practise to have an earth present, not sure if it is double insulated.

EDIT
The siemens stat I posted above is not nessecerilly the one the OP has in greece.
That was to explain the T1 T2 contacts

BS3036 said:
Seriously Rocky? I can't see that on the data sheet.
Click to expand...
If you could see as far as Greece I would be amazed :)
 
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