Cylinder stat wiring

[lrowner]

Hi all, first post from a newbie so apologies if I'm not quite up to speed with forum-use.

I'm a competent and experienced DIYer and I'm sure this should be simple, but I don't want to guess....

I need to replace an ACL HTS2 cylinder stat, which has three wires soldered into it - from the factory, I assume. I haven't bought a replacement yet, but I realize that a new stat from any maker will probably have three terminals labelled C, 1 and 2. Only trouble is, the terminals inside the old stat aren't labelled, so I don't know which is which.

Looking inside the junction box one wire obviously goes to the 3-way motorized valve, but the other two disappear into the wall and I can't trace them. I've looked at the installation instructions from Drayton, Honeywell and Danfoss but can't find the info.

Thanks if someone can help.

 

[Butchybutch]

Common Red = C
Demand Black = 2
Satisfied Yellow = 1

Try this and good luck!!

Brian

 

[MANDATE]

Should be easy enough to test. It is basically a two way switch. One input, but two outputs (not at the same time)
With HW on, turn stat up to create demand (not satisfied condition) test each terminal. One will not be live and this leads to the grey of the motorised valve.
With HW on, turn stat down to create satisfied condition test each terminal. again one will not be live and this leads to boiler.

The terminal live on both tests is the C (common) from programmer

 

[lrowner]

Thanks butchybutch and mandate. It sounds straightforward enough, so out with the screwdriver tomorrow. Thanks for the help.

 

[Yorkshire Gas]

Red = C
Black = 1
Yellow = 2

And that's for certain.

Cheers bye

 

[picasso]

After 6 years he just might have it sorted

 

[ianmcd]

Red = C
Black = 1
Yellow = 2

And that's for certain.

Cheers bye

Really ???

 

[AGAS]

Red = C
Black = 1
Yellow = 2

And that's for certain.

Cheers bye

nope that isn't for certain

 

[bernardgreen]

And that's for certain.

East of the Pennines maybe.....

 

[dilalio]

Aren't only death and taxes for certain?

 

[Yorkshire Gas]

Hi I put this as a point of reference for myself so I didn't have to remember it.

I've just had to do the same thing again. What I said is correct, as you know the HTS2 (not3) has its wires soldered on. So how it could be wired any other way I don't know

Thanks

 

[stem]

Handy conversion table for HTS 2 & 3

 

[Yorkshire Gas]

Thanks, I knew it was right. Haha