If it is generating a bit stream then chances are there is a microcontroller generating it in the first place. There may be an option here of disassembling its code as well if it is possible to read it out.
Yup. certainly doable. The only problem you sometimes find analysing this type of kit, is before long you have it on a bench surrounded by £50Ks worth of test and development gear. Fine when it is someone else's kit, not quite so practical when you nee to provide it yourself!
Quite agree, I would not go messing about with the boiler at all. The most elegant attack would be to work out how to talk TR2 and simulate that. If that is not going to be easy, then using a real TR2 as you suggested could be equally effective.
Device not present, means boiler under control of internal timer only.
Possible, but I would expect it is more complicated than that. With the TR2 in place it is probably either maintaining a two way dialogue with the boiler (not that likely since they did not provide dedicated wiring for the back channel), or at least sending a constant stream of information. The actual burner control will then still be managed by the boiler, and the on/off decisions made by it, but that decision making process will now be taking account of the data available from the TR2.
With this level of sophistication is makes much more sense to view the TR2 as a peripheral sensor, rather than an external controller.
3 wires.
You are assuming that the TR2 is acting as a controller and sending a switching signal. It may just be acting as a sensor and delivering realtime temperature and user control data. The boiler doing the grunt work with the data.
Possible, but at an as yet unknown cost.
Right. So effectively there is a link from 'live in' to 'fire up the boiler'
However I cannot see how replacing this with an assembly of switches that may be open, can affect anything..oh..wait up.
I think I see.. when the 'text display' calls for heat, opening this link stops the pump boiler?
Hence your point about removing the TR2, since it also controls that function..
So remove link
Power all MV's via stat's from LR and the neutral. Series parallel connect all MV switches to LR line and LS line.
Robert is a relative? Then the text display acts as a master timer, and the internal valve simply toggles between hot water, CH and off?
So when circuit open the boiler is on 24/7 with the timer interrupting to switch off or on.
I doubt it is two-way communication. Just the TR2 giving a resistance for the controller to act upon. The common way of doing it.
It appears to be jus a sensor, although I have seen no picture of it or details of it.
It is also claimed to be an optimising stat. Now this functionality could be in the boiler software, or some form of historical logging could be implemented in the stat, and information based the logged data also passed to the boiler.
You would need a DSO or Logic Analyser on the line to get a feel for what is happening.
There are three wires to the TR2. A smal three contact relay (£5 inc base for Maplin) could take all three wires in and out, either all open or all closed. The relay energised by the zone valve end switches. This TR2 could be:
Stat/programmers could be in each zone energising the zone valve. The TR2 is then only to make up the circuit, not temperature control (unless used as high limit), which is done by the wall stats in each zone. Simple. Sorted.
This has jogged my memory! That's the external control, likely 230Vac.
WB are of course hoping you will buy into their proprietary control systems.
`Yeess,,,, and if it's encrypted.......
Exactly. That's why I suggested looking at places where it's analogue components and where if it goes class F, the loss is small
I know that you wouldn't understand how to do it, but if there is no other way to control the boiler, this is the lowest risk option.
You are making a very big assumption that the interface between the TR2 and the boiler is analogue in some way. There is no evidence from the WB docs to support that.
Until you discover that the interface is digital and that this therefore doesn't work.
Even if the firmware of the controller isn't set up to do that?
There's a big assumption here that the link will actually perform this function. It may do. OTOH, it may be monitored by the controller firmware and that is configured not to use it.
It is possible that WB have conveniently ignored this of course on the argument of wanting to sell TR2s at £45.
Equally, this means avoiding mentioning a feature which makes the boiler much more useful
What a crock of s*it. Most commercial controller systems use some form of proprietary digital signalling.
Next time, do your web site research a bit more carefully.
On Wed, 11 Jul 2007 12:48:46 +0100, John Rumm mused:
The TR2 also has a 4 position switch for selecting different operating conditions, timed, setback, off and constant IIRC, which uses data stored in the textdisplay for the setback and on\off times.
even more daft now.
What I know is that the terminals of the TR2 need not be linked. Nothing connected and the boiler is on. Connect and the TR2 is influencing. Just open and close the three wires and the boiler is either on or off.
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