If you get around to implementing TPI on the Vera, let me know 
I’m planning on adding a second Horstmann thermostat and boiler controller, but with both thermostats directly controlling the boiler, I will lose some of the advantages of TPI.
I do not fully get this. TPI (Time Proportional Integral) would mean that Proportional Control (The P in TPI) is exercised. That means that rather then switching a boiler on and off you will set the boiler to variable heating output (e.g. heat on to 60%). But this is not what the HRT4-ZW can do, it can only switch on and off. Looking through the documentation you can see that the TPI settings restrict the switch to a number of heating cycles per hour (6 for a gas boiler). That effectively means that the boiler should not do more then 6 on/off operations per hour.
I suspect that the TPI is a marketing term and not really a fancy algorithm at all. Setting vera to decide every 10min if the boiler should come on or off and employing a small hysteresis (1 degree works fine) to prevent oscillation makes a decent control. That is a pretty stupid control algorithm (let alone that its missing a proof of stability) but it works and I suspect it is as good as the TPI algorithm in the HRT device.
If I recall correctly, TPI is simply a PID process with the D taken out. Every heating cycle (typically 10 minutes) it does the calculations and decides how long to run the burner in that 10 minute cycle. If the output of the PI controller is 0%, the heater stays off. At 100% it will burn during the entire heating cycle. At 50% it will burn for 5 minutes, then switch off for the remaining 5.
The PI controller does not really use a fancy algorithm, but what might be tricky is setting the right gains for the proportional and integrating components, though I suspect that these are not overly critical.
Maybe I should get something to log the room temperature accurately and try both algorithms, it would be interesting to see the difference. I suspect that you’ll get temperature swings of several degrees even with a 1 degree hysteresis (by the way, do you even need the hysteresis if your controller is on a 10 minute cycle?). Even a simple proportional controller should do a lot better at keeping the temperature steady, and it might not even be necessary to add the integrating component.
One problem I see with a PI control scheme is that the temperature is reported in Vera in whole degrees, and it might not perform all that well on such a low resolution 
I had it more or less working. Therostat and reveiver paired with Vera. Controlls on thermostat functioned, but setting the heat from within Vera did not work. However… Then I installed UI5… Thermostat app’s didn’t work anymore. I removed them and tried to pair them again with Vera. But Vera does not see them anymore.
Anyone has experience with this?
Yes I had a terrible time. UI5 didn’t work for me in any useful way so I downgraded to UI4. I forget exactly why but that didn’t work either and I had to redo the inclusions from scratch.
I reset the Z-Wave controller within UI4 and then went through and re-inclued the thermostate and the actuator. Had to try it a few times with various combinations of the instructions earlier on this thread, but I was able to pick them up again eventually
Hi,
Can anyone help me how to attacht asr-zw to my nefit?
gr Hendrik
It should attach just like (and replacing) your current thermostat. If you can show how the current one is attached and/or post the model nr. of your Nefit boiler, perhaps we can help
Thanks for your repley.
My Nefit boiler is a Nefit Fasto Ecoline. When you see my attachment in the first post the curreent thermostat is connectted with the Red and Blue wirres.
I think i must connect 2 wirres to the ASR. I have the options N, L, 2,3,4.
gr Hendrik
Hook up L and N to the 220v mains Live and Neutral respectively. Connect the red and blue wires from your heater to terminals 2 and 4. Power up the ASR and hit the On button, the heater should turn on, and turn off when you hit the off button. If on and off are reversed, use terminals 2 and 3
Has anyone so far managed to modify reliably the setpoint from vera (UI4 or UI5). I thought I did not need this function but now I would like to have it …
In UI4 you can reliably change the setpoint, but the thermostat does not report the new value back to Vera so the GUI never updates. I have set the wakeup interval at the minimum value (256), and use the following LUA code to change the setpoint and update the GUI at the same time.
luup.variable_set("urn:upnp-org:serviceId:TemperatureSetpoint1_Heat", "CurrentSetpoint", NIGHT_TEMP, DEVICE_HUISKAMER)
luup.call_action ("urn:upnp-org:serviceId:TemperatureSetpoint1_Heat", "SetCurrentSetpoint", {NewCurrentSetpoint = NIGHT_TEMP}, DEVICE_HUISKAMER)
Of course, if the thermostat doesn’t accept the new setpoint, the GUI will still be updated. However, so far the thermostat has updated every single time.
not working for me. I can dial a setpoint at the HRT and it shows up in UI4 immediately. However, I cannot set the setpoint from UI4 (also not with your method and having set to 256s interval). Communication seems one way here. I guess vera tries to transmit and realises the HRT is sleeping. Then vera should try later when the HRT wakes up. Is there a way to check this is actually working?
Have you tried changing the setpoint from Vera and checking the thermostat’s display to see if the change made it through, after waiting a while? I have found that Vera does transmit the new setpoint when the thermostat wakes up next, using either Luup code or the GUI to change the setpoint. The display of the thermostat will change to reflect the new setpoint
Yes I checked that. There is no update on the HRT display. I waited quite some bit. What vera version are you using? Maybe there was an update; maybe you have an updated HRT firmware?
I use UI4 version 1.1.1338. I have also tried this device using the most recent UI5 firmware but I couldn’t make it work; the behaviour was exactly as you describe. Reverting back to UI4 fixed this.
I have the thermostat paired with the boiler controller but I think that shouldn’t make a difference. Has the low wake up interval actually been set in the thermostat? I often have to do a “Configure node now” in the GUI to make that happen.
Vera reports my thermostat as version 2.2.78.4.0
I am on version 1.1.1245 and the HRT has 2.2.78.4.0.
So I wonder if the newer version 1.1.1338 would do the trick. Where would I get this version for an update?
Isn’t 1.1.1338 the latest official release? Try updating through your Vera GUI: Advanved->Firmware and see if the option to upgrade is there. If it isn’t, backup your Vera (Advanced->Backup) and visit http://micasaverde.com/vera2?beta=1338 and follow the instructions.
Well, my system does not offer it. I guess I have to use the link you provide, thanks. Is there somewhere a list describing changes in 1.1.1338?
Where do you place your LUA? In the scenes that set your thermostat to day & night temperatures?
Thanks
a software update fixed this problem. Now I can set the setpoint.
Some other observations:
When I set a setpoint in UI4 it takes some time until the setpoint is transmitted to the HRT4. If in the meantime someone uses the dial at the HRT4 it will be overwritten. Basically, a manual setting of a setpoint does not cancel the pending setpoint transmission of vera.
Also, I was looking for the lua code of the thermostat. I cannot find the implementation file. Where would that be? If can get hold of these it may be possible to fix these things…