Wiring help - Horstmann coronet 425

[Coleton123]

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• Coleton123
• 29 Mar 2015
• 1

Had to move my programmer but now my hot water is working but not my central heating. I think the wiring is set up incorrectly.

Can anyone help with explaining the correct set up? I've attached a photo of how it is at the moment

Thanks

 

[OwainDIYer]

How was it set up when it was working?

That wiring by the way is truly horrible. Haven't you heard of cable and cable clips?

 

[Coleton123]

Thanks for the reply,

I've not clipped anything because I'm still trying to establish which is meant to go where. Didn't want to clip it and then have to unclip when I already know the wiring is incorrect.

I don't know how it was previously hence why I'm asking if anyone knows the correct set up!

 

[45yearsagasman]

I doubt anyone will be able to sort that out without knowing what type of system you have and what controls are connected to it. ( zone valves, thermostats etc )

 

[stem]

It's difficult to see what wires are in some of the terminals due to the angle of the photo, and it will be a bit of a guess as to where each of them go at the other end, because it's down to the installer’s preference and method of installation. So, if any of my assumptions are wrong, please say so.

First of all, check that the wiring leaving the programmer goes to the correct places. I’m assuming here that you have a 3 port motorised valve, room thermostat and how water cylinder thermostat.

The wiring terminals for a Horstmann 425 left to right (or as in your photo bottom to top) are:

E = Earth terminal
N = Neutral connections
L = Live connections
1 = Hot water 'on' (Switched live to 'on' at hot water cylinder thermostat)
2 =*
3 = Hot water 'off' (Switched live to 'satisfied' at hot water cylinder thermostat and motorised valve grey wire)
4 = Central heating 'on' (Switched live to room thermostat)
5 =*
6 =

*You will also need some connection to terminals 2 and 5 as these are the supplies to the programmer’s internal hot water and central heating switches.

If your system’s control components are 230V, then the live terminal should also be linked to terminals 2 and 5. Did you remove any links whe you moved the programmer?
The puzzle here is that without an input on terminal 2, there is no way terminal 1 (hot water on) could become energised when the programmer switches 'on' the hot water, yet you say it’s working?

Here's a wiring diagram

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• stem
• 30 Mar 2015
• 1