Programmer connection issues

[Donald welsh]

Hi all new to site looking for advice. Horstmann centaur plus c27 gave up the goast late evening. So nip to shop got a Drayton LP522. Have a gravity feed system 2 X 2 port valves and pump. Boiler has no switch live.
Pictures show the way my control box is wired up. And a picture shows back plate wiring from old programmer.
If I'm correct the programmer must be set to P on the back ??.
Cables upto 3amp switch load 240v.
Cables to control box are feed 240v
Programmers live neutral and earth and She on and Htg on.
Do I need more connections on back plate to get programmer to work

 

[stem]

Hi we can tell you are new. You've posted a question that should be in the central heating' forum, in the 'forum information' instead.

The Horstmann and LP are simply two channel 'on' and 'off' switches and so perform identical tasks

The Horstmann has the following connections

And the Drayton has just the same connections

So they are exchanged like for like, you won't need any more wires than you have now.

As you have two 2-Port motorised valves, the mode of operation should be set to 'pumped' not 'gravity'

 

[Donald welsh]

Stem.
Thanks for that will try it again when I get in from work

 

[stem]

You're welcome, and I see the mods have moved your post to the correct forum for you.

 

[Donald welsh]

Connected programmer but when I switch on the mains input the programmer will light up and then the fuze blows

 

[stem]

Then either you have not moved the wires across exactly as they were. If you have moved the wires

N to N
L to L
3 to 3
4 to 4

Then nothing should have changed.

Or there is a fault elsewhere that is why the original programmer gave up the ghost, may be something else has changed or been disturbed. Are the wire in the terminal block at the back secure, and not shorted somewhere.

It's the same concept as changing as one light bulb for another.

Now you have blown a fuse it's possible you have damaged the new programmer too.