Drayton RTS8

[dawndriver]

I have just finished installing a complete heating system but the only thing I'm stuck on is the Drayton RTS8 stat, I'm just not sure how it should be wired, so hopefully some helpful chappy can point me in the right direction.

The setup is as follows. A combi boiler which has a permanent power supply is currently being controlled via a Horstmann CentaurPlus C17 by simply supplying a negative to the circuit. I would like to include the stat in the setup but what I thought would be a straightforward job has left me a little confused. Four connections on the stat N 1 2 L, instructions state I should have neutral first then the load on number 2 and finally live at the end.

When using a test meter on the terminals 2 and L they connect when the stat contacts close, This would mean giving a switched live feed out, however, I require a negative feed. Can anyone suggest how I might wire this to give me a negative out?

To be honest I've never wired up a stat before so any help would be appreciated.

 

[EFLImpudence]

Why do you say you require a 'negative' feed?
Where have you found this requirement?

There is no such thing in Alternating Current installations.


You will require the thermostat to either:

interrupt the switched live from terminal 4 of the programmer or

connect the two appropriate terminals in the boiler.

 

[dawndriver]

The reason for the negative feed is because the switch on the boiler to switch on the heating uses the negative feed. If I find and use the live feed it will switch of the whole system, which I don't want because I want to keep the hot water on permanently.

 

[Whitespirit66]

To be honest I've never wired up a stat before so any help would be appreciated.

You don't say!

Not sure what boiler/system you have, but chopping into the wiring for the on/off switch isn't the way to go about it.

More details needed.

.

 

[dawndriver]

I can do without the sarcasm.

I did not chop in to any wires as you put it. It's a warmflow combi boiler and it specifies in the manual where to connect a stat, between terminal 5 of the connection block and number 28 on the pcb, this is a neutral wire.

 

[mogget]

In this case you would be better off with a 2-wire thermostat with volt-free contacts such as the Drayton Digitstat+.

The RTS8 isn't a great stat to begin with and works particularly poorly in 2 wire mode.

Only thing is you won't like the Digistat+ if you don't like TP control. On the newer software version you can choose between 3 and 6 cycles per hour. Previous ones did 3 cycles only.

 

[dawndriver]

Thanks for your input. I certainly have no objections to trying something new and I may go down the route of the digistat

 

[mogget]

Just as long as you are sure what you are doing... you have the manual but I don't know your boiler.

If you are interrupting a neutral then the brown conductor in the cable you use should be sleeved blue at either end (heatshrink tube works well for this).

Do you have a separate programmer or is it built into the boiler?

 

[EFLImpudence]

between terminal 5 of the connection block and number 28 on the pcb,

I don't know if I am looking at the same model as yours but one does, indeed, state that.

this is a neutral wire.

NO IT ISN'T.

A neutral wire is that which completes the circuit fom a load back to the supply.

 

[picasso]

All the stat is doing is interupting the live supply to the ch



View media item 72066

 

[mogget]

And that is why I cautioned that I don't know that boiler

I still think the Digistat is a far better option than an RTS8 though.

 

[D_Hailsham]

It's a warmflow combi boiler and it specifies in the manual where to connect a stat, between terminal 5 of the connection block and number 28 on the pcb, this is a neutral wire.

I assume you are referring to this diagram:

Untitled

• D_Hailsham
• 19 Jan 2014
• 1

The Neutral is connected to the switched live of the stat switch via the anticipator resistance. The live side of the switch connects via terminal 5 to the boiler CH switch, as in this diagram:

Untitled

• D_Hailsham
• 19 Jan 2014
• 1

Modern digital stats do not have an anticipator resistance (which is there to increase the accuracy of mechanical stats), so all you need with a digital stat is to connect one side to T5 and the other to T28.

What sort of time control is there? Why not fit a programmable stat?

 

[dawndriver]

Thanks to all for the useful info. I decided the best route is, as suggested, to use a programmable stat and I've gone for the Horstman C7, I am also using the Horstman C17 time switch.

 

[picasso]

You dont need both, the programmable stat gives you complete time and temp control over the central heating.