Replacement Stat and Controls

[olly_hawkeye]

Hi, I am new to this so bear with me. I have a broken Sunvic SP100 (just stopped working) and I have bought a Horstmann C27 to replace it. I was hoping that someone could point me in the right direction as to what needs to connect to what as a direct swap. I have not disconnected anything yet and was hoping that I could just mark up the wires and then reconnect.

Also I have a new wall thermostat which is a Horstmann DRT1 which is to replace a Sunvic TLX2259, again I am looking for help with a direct swap.

Any help would be greatly appreciated, as I feel it should be an easy job once I have the information.

Thanks in advance

Olly

 

[Agile]

It might be a slightly bold person who tries to give you any advice without any knowledge of what boiler and system you have.

Some people follow conversion charts but I would always trace the existing wiring as I can never be sure that any existing system is correctly wired.

Tony

 

[olly_hawkeye]

My apologies Tony, I guess I was hoping for a straight swap with just the terminal numbers etc....

I have a potterton prima F boiler and a Danfoss HSA3 valve if that helps.

Thanks

Olly

 

[Agile]

It may well be a straight swap but any mistake and your new bits are blown up!

I would not risk advising you. In any case I wire up according to the circuit function and dont just follow numbers.

Tony

 

[ChrisR]

The SP100 connections are
1 hw off
2 hw on
L
N
E
Spare
Spare
3 ch common
4 ch off
5 ch on

The stat was
3 Common
1 Demand
none (Satisfied)
4 Neutral

Hope that's a little more useful than the advice given above!

 

[olly_hawkeye]

Thanks Chris thats great!

I do however remember something being connected to the spare when I looked at the connections on the back of the SP100, is it likely that this is for the stat?

I understand that any advice given is to be treated only as advice though

 

[olly_hawkeye]

Sorry I am talking rubbish. Nothing in the Spares however there is a link between the Live and Pin 3 and nothing in pin 4.

So I am fine with everything there but that there is a link and that there is nothing in Pin 4.

The C27 it seems requires CH OFF and not CH Common.

Any Clues?