Hi
I currently have a Honeywell room stat fitted that i need to replace. The stat has 3 wires - red, black and unsheathed.
I want to fit another room stat (Sunvic TLX 4101) connection block is numbered 1, 2 and 3.
Cannot understand the wiring diagram or what is 'com' , 'dem' and 'sat' .
It shows com is 2, dem is 1 and sat is 3.
Any assistance appreciated
Fred H
I believe the sunvic has different wiring to the honeywell. The wires you have to the honeywell are earth( unsheathed) with the other two being live in and live out when the thermostat operates. The sunvic would require a live and neutral in with a switched live out so you would need to run another wire. The easiest way to do it is to get a thermostat that would replace the honeywell as a one for one
Why would the Sunvic need a neutral? I'm not familiar with said device but from what the OP says about the terminal markings it doesn't.
Com = Common (Live In) Dem = Demand - Will be connected to Common when there is a demand for heat (Switched Live Out in this case) Sat = Satisfied - Will be connected to Common when there is no demand for heat (Leave disconnected)
Mathew
Thanks for the assist. will try find another Honeywell
Some thermostats draw a little current when 'off' - something to do with reducing switching delays.
In which case it would have a terminal marked for such.
Mathew
There's nothing wrong with the Sunvic you've purchased! Both your Honeywell and Sunvic are 2-wire stats (disregard the 'sat' connection as an apperent third - it's not).
Connect Red to Com (2), Black to Dem (1), and the unsheathed cable (which ought to have a green/yellow sheath on it but often don't) to the Earth terminal (if provided) or secured out of the way. Don't chop the earth just because it may not be required for this stat - the next replacement may need it. Leave the Sat (3) terminal not connected.
Mathew
Yes, The Neutral.
On Sun, 02 Apr 2006 09:35:10 +0100 someone who may be The Natural Philosopher wrote this:-
Some mechanical thermostats have an accelerator heater, which needs a neutral wire. The heater is on when the thermostat is calling for heat. Thus it switches off earlier than it would otherwise do and thus reduces overshoot. Electronics can do the same thing mathematically.
Ah, I stand corrected. I know all mine are like this anyway.
How does one stoop them making 'orrible thee second arcing noises too..
We lose the TV completely when some cut in and out..never Id'ed which ones tho.
The bimetal ones (even with heater) open and close relatively slowly compared with a relay.
Electronic ones tend not to do this.
They should have components to stop this, normally a capacitor/resister stubber network. Maybe if they are old the caps have failed.
Dave
What Neutral?! It's got a 'common', 'demand' and 'satisfied' - nothing else!
Mathew
They all did it from new..
In which case, its not one that needs a neutral is it?
Are they electronic or mechanical (i.e. bimetallic strip)? As Andy hinted, electronic ones will likely be far better in this respect.
Mathew
Yes. Any desire to connect the earth wire to the "sat" terminal should be resisted. It will go bang in a big way. A common failure mode when brain dead installers are around.
Christian.
Many thanks to all for having this conflab as it's answered all the questions I had - same as OP really except my original was a Satchwell TLX 2203. Somewhat annoying that the Sunvic website doesn't recognise the existance of the TLX 4104! Mike
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