Room Thermostat

[mikewhit]

Hi, The room stat on my system is a mechanical working Satchwell TLX 2356. I believe they have been taken over by Sunvic Controls. The wires are conected to four terminals, diagram at, http://www.tlc-direct.co.uk/Technical/DataSheets/Sunvic/TLX.pdf
I have been trying to source a Digital room stat with the same conectors but to no avail. Can anyone help or do I have to stick with my old 1978 stat.
Mike

 

[chrishutt]

I guess most digital room stats are "voltage free", meaning the switching contacts are not linked through the stat to mains voltage, as is the case with mechanical stats with accelerators that require a neutral connection.

You can use a digital stat. Just connect the switched live connections to the old stat to the new one, but isolate the neutral connection and any permanent live. Any internal timer (programmable roomstat) will be battery powered so won't require mains.

 

[mikewhit]

I guess most digital room stats are "voltage free", meaning the switching contacts are not linked through the stat to mains voltage, as is the case with mechanical stats with accelerators that require a neutral connection.

You can use a digital stat. Just connect the switched live connections to the old stat to the new one, but isolate the neutral connection and any permanent live. The clock will be battery powered so won't require mains.

Are you sure that would work with the wiring in the diagram I showed you?

 

[chrishutt]

No, the wiring's not the same, as I explained, but does it matter?

Look, you just want a switch operated by a temperature sensor. That's what a room stat is, digital or mechanical. If it's digital, you have a live in and a switched live out to the boiler/pump. What's the problem with that?

 

[mikewhit]

No, the wiring's not the same, as I explained, but does it matter?

Look, you just want a switch operated by a temperature sensor. That's what a room stat is, digital or mechanical. If it's digital, you have a live in and a switched live out to the boiler/pump. What's the problem with that?

Yes I understand what you mean but my wiring dia is the same as this one go to http://www.gasman.fsbusiness.co.uk/wiring.htm then scroll down to "Flow-share Wiring Diagram With Programmer Giving Independent Control of Heating and Hot Water" Do I use the sensor between the Calling and Satisfied? Many thanks for your answers so far.
Mike

 

[chrishutt]

Ah well, the Drayton flow-share is a rather different animal to a typical control system. Are you quite sure that's what you've got, with a Satchwell room stat, with three switched live connections?

If so, then you need a room stat with three switched live connections, a common in, a calling out and a satisfied out. In the Flow-share diagram they are terminals 3, 2 and 1 of the stat respectively. Many digital stats will have such a switching arrangement, so it shouldn't be a problem.

The earth and neutral connections to the stat in the diagram will probably not be required for a digital stat, but you need to maintain continuity of the neutral connections in the diagram. there may be a spare terminal on the new stat to park the neutrals, or you could use an insulated connector.

If you find a digital stat that you like the look of, post a link here and I or someone will confirm if you can use it. Try Honeywell, Danfoss, Drayton, Horstmann, Invensys, etc. The digital stat may be battery powered or might run off the mains, in which case you would need to modify the wiring to bring a live and neutral to the stat (not difficult).

 

[mikewhit]

Ah well, the Drayton flow-share is a rather different animal to a typical control system. Are you quite sure that's what you've got, with a Satchwell room stat, with three switched live connections?

If so, then you need a room stat with three switched live connections, a common in, a calling out and a satisfied out. In the Flow-share diagram they are terminals 3, 2 and 1 of the stat respectively. Many digital stats will have such a switching arrangement, so it shouldn't be a problem.

The earth and neutral connections to the stat in the diagram will probably not be required for a digital stat, but you need to maintain continuity of the neutral connections in the diagram. there may be a spare terminal on the new stat to park the neutrals, or you could use an insulated connector.

If you find a digital stat that you like the look of, post a link here and I or someone will confirm if you can use it. Try Honeywell, Danfoss, Drayton, Horstmann, Invensys, etc. The digital stat may be battery powered or might run off the mains, in which case you would need to modify the wiring to bring a live and neutral to the stat (not difficult).

Many thanks for that, I can see the line we are going down now after your confirmation of my thoughts on the diagrams I have. I have been looking all over in the UK for one but have only found the ones that have a programmer as well. I will look at the maunufacturers you have shown and see what I can find, I will let you know what I find, Unless you know of a supplier. Mike