Hi fellers,
I have been installing a couple of floors of Daikin vrv and have a theoretical question for you.
The positions of the condensers compared to the indoors was more or less central and I rang daikin technical to see if it would be ok if i ran the 2 core transmission wiring (F1,F2) to the nearest unit in the centre then tee off one left and one right to the rest of the indoor units which would have drastically cut down the length of wiring compared to starting at one end then daisychaining all the way along to the last unit.
Needless to say they shot me down in flames saying I had to stick with the daisychain method.
They say that if you "star wire" any part of the system it will "confuse" it when it self addresses on initial start up.
I did as I was told and all is well but what I want to know is why?
Given that the wiring is just linked in then out off of the same terminals on each unit, i.e. wired in parallel like sockets on a ring main (without the return from the last unit to actually make a ring), surely the laws of electricity mean that all units receive voltage simultaneously on start up and not "jump from one unit to the next" as they address them selves.
The only thing I can come up with is that by daisychaining you are adding to the resistance of the wire after each unit and therfore guarentee there will be a different resistance to each unit. Whereas if you star-wire it willy nilly you may end up some units having very similar lengths of wire back to the condensing unit thus causing the "confusion" to the system.
This seems to indicate that the system is able to detect extremely slight changes in resistance in the wiring and uses this to systematically address the indoor units.
If this is the case then I could kind of understand it but if not then it seems to me that the daisychain idea is a complete crock and the condensing unit pc board uses some other way to randomly address the indoors and it should work even if you wire it however the hell you want.
I know its what they tell you to do and will do it as they say in case of problems as Im told if you mess up on initial start up the sytem saves a fault code and gives you even more grief.
Does anyone actually know or even actually wired it differently and what was the results.
I would love to know!!