Changing a room stat (wiring check)

[ste69]

Hi All - just quick one.

I'm replacing a mechanical room stat with a digitial one - The mech one is a Potterton PRT 100 - the terminals are marked 1,2,3. 1=red. 2= yellow, 3=blue

The new one (drayton digistat 1) has 1=common, 2= satisfied, 3= demand.

All i need to know is which colour from the existing set up goes with which terminal on the new stat.

Or is it as simple as red=common, yellow = satisfied and blue = demand????

Just thought I ought to check really

 

[baxpoti]

//wiki.diynot.com/electrics:how_to_replace_a_room_stat

 

[ste69]

Cheers for that but all I need to know is "which wires are the common, call and satisfied" They're not labelled and I dont have the wiring diagram for my old potterton one.

At the moment there's red -1, yellow - 2 and blue - 3

On my new stat, 1 is common, 2 is satisfied and 3 is call. So if this is the same setup as the original, Red would be the common connection, yellow the satisfied one and blue is the call for heat -

does this seem logical or am I missing some obvious step here?

Thanks again in advance for your replies

 

[ChrisR]

Suggest you get a simple meter with volts and continuity on, then you can test things like this (Wickes do one for a tenner)

I have looked it up for you and have the answer though, it says:

Common TL
Demand H
Satisfied C
Neutral N

Now about that meter...

 

[bernardgreen]

Hi All - just quick one.

I'm replacing a mechanical room stat with a digitial one - The mech one is a Potterton PRT 100 - the terminals are marked 1,2,3. 1=red. 2= yellow, 3=blue

The new one (drayton digistat 1) has 1=common, 2= satisfied, 3= demand.

All i need to know is which colour from the existing set up goes with which terminal on the new stat.

Or is it as simple as red=common, yellow = satisfied and blue = demand????

Just thought I ought to check really

Blue is neutral and NOT needed on the new stat. DO NOT connect it to the stat but use a piece of connector block to keep it from touching anything

Red should be live. connect to common,

Yellow should be switched live to tell the boiler to fire up. Connect to demand.

 

[ste69]

Just so I'm sure I understood the post

So nothing connected to terminal 2 of the new stat (marked SAT) just red to C (terminal 1) and Yellow (with little red sleeve on it) to terminal 3 (marked Call)???

 

[bernardgreen]

Just so I'm sure I understood the post

So nothing connected to terminal 2 of the new stat (marked SAT) just red to C (terminal 1) and Yellow (with little red sleeve on it) to terminal 3 (marked Call)???

Yes that is right. The Neutral was necessary for the mechanical stat but not for the digital one.

If you had put the neutral into the one marked SAT when the room was warm and the stat was SAtisfied the neutral and live would have been connected together and the fuse at least blown.

 

[ste69]

Great - I'll give it a go (once the missus has finished watching something on the telly) - then its power off and reconnect. Or am I safe to do it as long as the isolator is off at the timeswitch???

 

[ste69]

All done - Thanks a lot for your help here - It works a treat and no-one got blown up.

Thanks again - Great site