siclark wrote:As the spirit can part open the valve and keep adjusting it itself, it can keep a much tighter temperature range than a trv that is on or off and has 1-2 degree temp swings depending on whether it's on or off.
See below the valve being open approx 15-20% ( right axis) between 5 and 7pm. Keeping the temp stable (ignore my Mac crashing later that evening!)
I'm not completely sure what the graph is saying, but I think it ties in with something I'm unclear about on how the Spirit actually works.
At about 5pm the remote set point is set to 19C?. This sets the Spirit set point to the same value. The Spirit opens the valve fully, then very quickly drops it back down to, what, 10%-ish?
It looks like the temperature never actually reaches the set point, but hovers closely below it.
This looks like it explains my observations.
I have one Spirit on one radiator, in the same room as a wall stat. This wall stat controls the heating.
When the room is 17C, according to room stat, the Spirit is reporting 16.5C.
Set the stat to 18C, heating comes on.
The Spirit rapidly rises to around 23/24, so I had to set its set point to 24C for it to come on at all.
What i noticed was that the Spirit controlled radiator would be hot for a while, then become warm, followed by lukewarm. Checking the Spirit temp, it was around 23C.
Thus the Spirit was backing off the radiator, meaning the room stat was not reaching 18. That room was not so warm, every other room with full on radiators were turning into ovens!
I could set the Spirit set point to something very high, 26 say, but if someone changes it locally they are not going to put in 26C. There is a temperature offset in the settings, but that only seems to go to 5C, which may not be enough (I have yet to try this.)
This is why I was interested in the valve opening and how I could get visibility of it.
On looking in the logs I noticed the Spirit was transmitting:
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received "[device]' status update brightness N
Where N seems to be between 0 and 100. I'm assuming this is actually the valve opening percentage.
Sam.