Adding a wireless thermostat

[Rob]

Could someone help me out with the wiring for this please - I can't figure out the different terms used. I've posted info here:

Rob

[Roger Mills]

Is the wireless stat *just* a stat, or does it also do timing? If it also does timing, the Danfos timer is redundant, and needs to be set to constant.

Either way, I assume that you wish to connect the wireless stat to the timer in the position shown for room stat?

The room stat shown is a mechanical one which has an accelerator heater (to reduce hysteresis) and thus needs a comnnection to Neutral. The wireless stat is digital and needs no neutral connection on the switching bit - although it does, of course for its mains power.

So LX (Common) on the stat needs to be connected to 1 (Com) on the timer, and L1 on the stat needs to be connected to 2 (Call) on the timer. *Don't* connect anything - especially neutral - to L2 on the stat - otherwise you'll get an expensive bang when the demand is satisfied!

[ARWadsworth]

I have to disagree. Terminal 3 on the timer is Common and terminal 1 is Call. Terminal 2 is spare. Danfools have weird terminals sometimes;-)

You need to take terminal 1 from the timer to the LX terminal on the stat and terminal L1 of the stat to terminal 2 of the timer. This would by pass the room stat with the remote room stat.

Adam

[Roger Mills]

Isn't that what I said? [See above - LX to 1 and L2 to 2!]

[ARWadsworth]

Yes. And I repeated that bit without realising!!!!!!!!!!!!

It was the bit about the timer having terminal 1 as Common and terminal 2 as Call that I probably picked up on.

Adam

[ARWadsworth]

Nearly, you said on your first post

[LX to 1 and L1 to 2!]

Blame the spell checker/wife/gremlins/British Gas/South Yorks Police or some other deviant for that one:-)

Adam

[Rob]

Just a stat.

Yes, connected to timer.

When you same room stat - I take it you mean the Dayfloss timer?

Many thanks Roger, appreciated - I just had a call back from Siemens (which I wasn't expecting to be honest, especially for a non-trade enquiry), and he said to connect LX and L1 only, L2 is redundant in this application - which seems to be exactly what you say.

Rob (posting from google groups because Thunderbird seems to be having a tantrum)

[Roger Mills]

I meant the one (of unknown parentage) shown in the timer wiring diagram.

Good!

[Roger Mills]

You're right, that was a typo - but I *did* get it right first time (the one you agrued with)!

[Rob]

Goodish! I've had a good look. There's no wiring, or indeed connection anywhere, to connection 2 on the timer. So wiring the thermostat to connection 2 won't do anything. The only wiring from the boiler is to connections 1, 3, earth, 5 and 6. I've put a couple more pics at:

wire LX1 and L1 to connection blocks 1 and 3?

Thanks, Rob

[ARWadsworth]

So there is no existing room stat then on your system?

Adam

[Rob]

No - it's just controlled by the timer (and room TRVs).

Rob

[ARWadsworth]

That makes sense

You cannot just wire LX and L1 of the Siemens up to terminals 1 and 3 of the Danfoss. Nothing would go bang but it would not work!

Just move the connection from the boiler that goes to terminal one on the Danfoss to terminal 2 on the Danfoss and then wire the Siemens LX terminal to terminal 1 of the Danfoss and L1 of the Siemens to T2 of the Danfoss. (Two wires at L2 of the Danfoss when you are done).

Adam

[Roger Mills]

I think I'd need to see it in the flesh, and trace connections between boiler and timer before feeling competent to comment further.

[Rob]

OK, thanks. Given up for today - too cold. Just one thing with your suggestion - wouldn't it take the timer out the loop?

The only connections on the timer, that lead in to the timer unit, are -

1 and 3: appear to be the on/off switching contacts; and earth, 5 and 6 (power the timer). Connection 2 on the timer is just a terminal block that goes nowhere. Without a connection to 1 on the timer, how would it work? ('just would' is good enough for me BTW).

Rob

[John]

Do you need the timer if your thermostat is programmable? Just set a low temp for "off"

[Rob]

TBH I've never used the timer - it's just used as a switch box because rise/bed times are pretty erratic round these parts.

It would be nice to have the facility for the rare occasion it might be needed - warm mornings wouldn't be moaned at, for example. And the thermostat I've bought (Siemens RDH10RF) doesn't have a timer.

Rob

[ARWadsworth]

Reread it.

There is a connection to term 1, it is to LX of the Siemens. You are back to the second picture down but using a siemens remote receiver instead of a room stat.

HTH

Adam

[Rob]

Got it - all connected up and working perfectly. Thanks very much.

Rob