I have a big problem with the version 1.7 of the Heatit Zwave Thermostat (HEAE5430499).
I use one device of version 1.4 for more than a year now with success in my house with the internal temperature sensor. I now bought 14 modules for my new built home (I want to move in within 6 weeks) and today I noticed when testing these devices that the behaviour has drastically changed (although the product number ist still the same (5430499)). The device only displays the set point temperature and no longer the actual temperature on the display. Even via ZWAVE the set point temperature is transferred to the controller as set point value und actual temperature value (which is absolute wrong). Additionally the heating control does not work reliable. I tested with 2 thermometers beside the device and the switching of the heating is not understandable. There seems tob e a big issue with the software and/or the internal temperature sensor in Version 1.7.
Like this the device also does not perform its job as a temperature sensor that reports the actual values to the Zwave central, so it is useless.
Has anybody an idea what I could to? Any help appreciated!
thanks,
Martin
Unfortunately I know exactly what is going on, having bought a bunch of the devices, experiencing the same problem, and then discussing with Vesternet
You probably noticed that the internal temperature sensor was inaccurate, floating up and down a few degrees hotter/colder than actual, probably because it’s located close to the (warm) internal components. The manufacturer brilliantly decided to deal with this by updating the firmware to essentially disable the internal sensor. When you select the internal sensor then it behaves exactly as you describe - completely useless. My fix for this was buying some cheap sensors (these), connecting as internal sensors, but then tucking inside the heatit’s hollow plastic frame before I fix it.
Even this isn’t perfect, as it records a temperature consistently a couple of degrees warmer than actual, but at least the error is fairly consistent, so I can adjust it with openHAB rules.
This is all very non-ideal, and I considered returning the devices, but unfortunately there seems very little competition for zwave thermostats. Positively scandalous that a manufacturer can ship a device that doesn’t work properly, and cover up the problem with a firmware bodge that disables a key feature. But there you have it!
Interesting… That explains why there’s a “requires external temperature sensor” statement on the Vesternet website even though the manual says it has an internal sensor…
I’ve also been looking for a while, and it amazes me that there are no decent thermostats.
What’s about the Danfoss Link RS room sensor (014G058)? It’s also zwave based and I’m using it with OpenHAB and it seems to be comparable to the Vesternet device.
I don’t know if it’s as “decent” as the Vesternet device… 
The other stupid thing about the heatit devices is that the display only shows temperature rounded up to the nearest 0.5C (although the sensor has 0.1C accuracy). I suspect this is another bodge to get around the inaccuracy of their sensor.
On the plus side, the heatit devices are pretty, and the zwave connectivity works fine - it’s a shame everything else about them is rubbish.
Thank you for sharing your experience, so I am not alone.
I meanwhile also got an answer from Heatit support, just one disappointing sentence:
Dear Mr …
This is a thermostat, not a thermometer.
With best regards/Med vennlig hilsen
That was all the reply to the same long problem description I posted here in this forum. Apparently Heatit is not interested in customer satisfaction and acts really ignorant.
They should say openly that an external sensor is a MUST, as all descriptions (even in the manufacturers product sheet) states the external sensors as additional options. And the old version worked fine without external sensors.
It is really strange that they let the device control the heating like this (option A for internal sensor is choosable for this), but then hide the most central information for that controll process - the temperature - and not show it to the user. So you have a blackbox controlling your home.
Alternatives are unfortunately really a problem, there are very few 230V mounted devices that are sensor and actor as well. Maybe MHO MH7 might be an option, but it is a bit too large for normal wall mounts. I ordered now one for testing.
I also ordered 2 different external sensors to check if they work with Heatit (Thanks Dan for that information!)
The Danfoss devices are just battery powered sensors so they do not provide the same functions as Heatit.
I will try to find a workaround…what a mess thanks to that product policy from Heatit… 
I guess one workaround would be to use the Danfoss sensors in combination with zwave relays on the 240V line
Heatit clearly have a lot to learn about both public relations and consumer law…
I tried a lot of alternatives now, but my wife would only accept the look of the Heatit devices…
@dan12345: Thank you again for the hint with the cheap external sensor. I meanwhile tried also 3 different NTC sensors with 10KOhm and they all worked great for temperature with the device. The one you proposed (36219I) is the slimmest and is the most adaptable to tweak it somewhere in the frame. So I order now this model for all thermostats.
It is absolutely incomprehensible to me why Heatit is providing the device without such a sensor (we talk about a little cheap cable with sensor priced at 2-3 € maximum in various online shops). Instead they hide the truth about their device and annoy all customers without even offering this solution when you contact the support. That is really poor…
hi@all and sorry for my late replay to this thread, but i have exactly the same problem as you guys.
I ordered the heatit because I was reading some time ago that it is possible to get it working without external sensor. But it isn’t
I’m now ready to give up (after a few sleepless nights) and buy such a 36219I sensor.
My question abaout it: How did you connected it with the heatit? On the back are only single connection ports for external sensors, but the sensor has 2 cables?!?
There are three connectors at the top of the device - one for floor sensors, one for external sensors, and one common connection.