Swapping central Heating programmer?

[reedluke]

I need to swap a programmer for my sister, she currently has a Danfoss 4033 programmer, (large time dial with on/off/timer switches for ch & hw).

The fuse blew in the spur feeding the programmer, when I've replaced it and now the timer is just giving out a loud buzzing sound. She has no ch or hw.

I have a Horstman C27 as a replacement, which says it has a standard back plate, but if I follow the guide for swapping the unit's, I'll have 2 wires left over! has anyone ever swapped these units? I tried following the instructions, but it didn't work so I panicked and put it back exactly as it was!

The Danfoss currently has 8 ports, market 1 - 8 (6-8 are N,L & E)
The Horstman has 6 ports + a separate earth connection.
The 2 wires I'll have left are currently in Ports 1 & 5 on the danfoss. (although port 1 is just a loop from the live feed)

Wires connected are a T&E feed, looped out to the boiler direct, then 2 3C&E cables going out to pump etc, there is no room stat.

Can anyone help? Am I making sense?

Thanks.

 

[ChrisR]

Randall 4033
1 L
2 ch on
3 ch off
4 hw on
5 hw off
6 L (link to 1)
7 N
8 E

You just connect like for like going by the descriptions of each connection.

 

[chrishutt]

To reinforce what ChrisR is saying, the Danfoss effectively has 7 ports since 1 and 6 are the same. So just put the wires to 1 and 6 on the Danfoss to the live terminal on the Horstmann.

 

[reedluke]

Thanks, that all makes it lot clearer, like for like.

Just one more question if anyone knows about the c27, altough I asked for a c27, On the front there is a small blank plate over the hw light and there doesn't seem to be a pin on the back of the programmer to connect to terminal 2. Does this sound like it might be a lower spec than I asked for (possibly a c21 etc). The pictures I have seen on the web have a light on the hw.

Cheers.

 

[ChrisR]

UNfortunately there's no Horstmann website. C27'sare common though and I've not seen one with the HW light blanked out! Sounds odd. C21 is the all-days-the-same version.

There would be a "combi-boiler" version for CH only, which I think would be called a C17. Sure you don't have that?

C27 connections go
1 hw off
2 ch off
3 hw on
4 ch on

so 2 is not one you'd need

 

[kevplumb]

this may help

 

[ChrisR]

Folding arms, adopting Chris Barrie sort of whine:
"I do believe you'll find that it will not"

 

[kevplumb]

that's why i said "may"

 

[reedluke]

Thanks gents,

I have just spoken to the Horstmann Tech desk, they reckon I've been sent the wrong unit, although marked up as a c27 it sounds like I've only got a single channel unit - just trying to get it replaced. Ordered it from TLC funnily enough!

Thanks for your help.