Wiring in a programmer/roomstat to a combi boiler

[Nick Lane]

Hi I am on the home straight to installing a complete ch system in my house. The combi is a worcester bosch 28i and I have a Horstmann centaurstat 1 to site in the lounge. Problem is although I found the ch a doddle to install wiring is not my strong point. The Centaurstat has four connections 1) Live (line) 2) Load (heat) 3)load (cool) and 40 Neutral (parking). The combi has two sets of three connectors one for the room stat and one for the programmer. The 3 for the roomstat are 1) RN (neutral) 2) RI (switched live)

3) RL (live) and the 3 for the programmer are 1) CN (neutral) 2) CI (switched live) 3)CL (live). So it appears that i will have 6 wires coming from the combi to wire to 4 terminals on the centaurstat so it seems that some trminals on the cetaurstat are shared. If anyone knows how to wire this I would be very grateful for the info. Regards Nick

[Dave Jones]

Ignore the 3 for the programmer, and ignore no.3 connection on the stat, and then neutral to neutral, live to live and Load(heat) to RI (switched live)

Job done.

Dave Jones

[Big Phil]

Is this assuming that the Stat is wired in series with the programmer though? Otherwise there is no time control to this system?

Phil

[Set Square]

Aren't we talking about a programmable stat, which does *both* timing *and* temperature control in a single device?

[Dave Liquorice]

Even if we are still having a conventional controller in series is handy as most programmable stats are not easy to manually force off by a single button push or three, where as programmers are. Also if you have noisey pipework it can be a bit annoying having the heating come on at 0300 just beacause the house has sunk below 15C. Heat it when you need it not just because some dum stat says so.

[chris French]

In 7 years of having a programmable stat on our system I can't say I've ever noticed that desire. If I want to turn the system off for some reason then I use the boiler controls. (as it happens there is timer as well in the circuit as the boiler has one built in, but I never touch it)

The Sat would only be saying so because that is how you had programmed it

If you don't want the heating to come on in that situation you would set a lower temp for that time period

[Nick Lane]

Many thanks for your help this looks to have solved my probs Cheers Nick

[Dave Liquorice]

Does that disable the HW as well though? I could turn the boiler off but then there would be no HW...

I guess so. But bear in mind that this place has drafty windows and little wall insulation. When the wind gets up it cools very rapidly and as I said "Heat it when you need it" and I tend not to sleep in the living room where the stat is. Bedroom down to 12C or lower is dealt with by a good duvet...

[chris French]

The Op was talking about a combi, I have combi also, I was really in my original post talking with regard to a combi. so yes, if I just want to turn off the heating and leave the HW I can.

Depends on the interpretation of 'when you need it'.

My stat has 3 temp levels, I set the lower one at somewhere like 8C I think (I forget exactly), I find that if it comes on at night then it's because it's pretty cold outside and it seems to keep the temp more comfortable - mostly because it heats p quicker in the morning.

For me it works fine, as I said I leave the timer permanently one, but YMMV of course