replacing a central heating programmer?

[NHW]

hi guys, my central heating programmer (horstmann 425 Tiara) timer wasnt rotating recently so i took it out to see if there was anything stuck and long story short a few bits and pieces fell out as i took it off the back plate.............so now i have to get a new one lol

i've never really looked into these timers before but i kind of understand the jist regarding direct fit ones and ones that will need the backplate changed etc but i just wanted to know how big of a job is it if i got one that needed a different type of backplate?

I just assumed that it was a case of taking a picture of the existing one so that you know where all the existing wires are and then swapping them around to the new backplate?

Also some of the jargon is also baffling me, does 1 channel mean that the programmer will only control either central heating or hot water and 2 channel means it will handle both?

i am currently looking online for one that is 2 channel, digital, 2-3 on/off programmes per day, gravity-fed compatible, so if anybody has any good recommendations i would much appreciate it. Thanks

 

[denso13]

It isn't difficult but you need to be comfortable working with electrikery. Yes, 2 channel will control hot water and heating independently but your system has to be suitable. You mention gravity HW which would suggest it isn't compatible.

Do you you know what type of system you have - do you have a room stat, cylinder stat or motorised valves?

 

[NHW]

hi denso thanks for the swift reply.

as far as i can see i have:

Horstmann 425 Tiara programmer

A thermostat in the hallway (nowhere else)

A cylinder stat on the tank

and also motorised valves

bearing in mind i only really know what the stats and programmer actually do, the motorised value i have no idea on its purpose but i googled it as you mentioned it and then took a look in my boiler room and noticed that it was there

 

[NHW]

You mention gravity HW which would suggest it isn't compatible.

hmmmmmm so in this case would i only be able to replace it with the exact same model?

 

[denso13]

Maybe upload a picture of your boiler/valves and what wires are at the programmer? Either way you can use a different programmer, just need to be sure of your system.

 

[NHW]

really appreciate your help denso

View media item 70899 View media item 70900 View media item 70901 View media item 70902

 

[denso13]

Looks like fully pumped and not gravity HW. Is there a model number on the motorised valve?

 

[NHW]

there sure is, seems to be BGMVSP-23 (mid position actuator valve)

which apparently is made by Drayton/British Gas.

View media item 70903

 

[denso13]

Fully pumped it is then and any 2 channel programmer should do the job. Perhaps http://www.honeywelluk.com/products/...Wired/ST9400C/

 

[denso13]

Compatibility here, page 17 http://www.honeywelluk.com/documents/all/pdf/wiring guide issue 16.pdf

 

[NHW]

ah thanks for your help denso, ill probably go for the one you recommended then

ermmmmmmmmmmm by any chance would u be able to advise me on the wiring aspect once it arrives?

if i cant get that model in a store then i may have to get another model as i think ordering it online would take a few days to arrive and dont think we could do without heating for a good few days haha

again thanks for your help

 

[NHW]

sorry one last question, do brand new (in the box) programmers usually come with their own backplates? because im just not sure if my existing one will fit with other programmers and it doesnt seem to mention on any of the descriptions or websites if they come with backplates in the box or not. Thx

 

[denso13]

Compatibility here, page 17 http://www.honeywelluk.com/documents/all/pdf/wiring guide issue 16.pdf

Wiring compatibility above which should be straightforward for most makes, if not someone here will advise. They will come complete with backplate.

 

[twgas]

New prog will come with backplate which will be reqd.