Is there a known issue with some of these or a known incompatibly with some fan forced heater models?
There is a known issue:
The very first production batch had a flaw which could cause that kind of noise.
Since you guys are early adopters, you could be the owner of such thermostats.
To my knowledge, this issue has been solved.
Mine are from 2016/07/05. Do you know from what date the issue was resolved?
This is what I’m trying to find out.
Just to be sure, where did you get this date from?
It’s printed on the bottom edge of the thermostat.
There’s another date 29 06 16, in the menu under 7.n.
I called technical support, they directed me back to the vendor, they’re processing an RMA for the return / exchange but are not sure yet if they’ve stock from a later production run available for the exchange.
James
Hi James,
It is highly probable that your unit has the issue.
The problem was fixed on October 21st 2016.
Please contact Stelpro’s customer care to organize a product replacement.
I contacted customer care, they’re sending replacement devices.
Thanks.
Replacement units arrived today. Units are dated 2017/01/05.
Have swapped one of the two, the issue is still present in the replacement. 
James
How many fan-forced heaters are linked to each thermostat?
The one I’ve swapped today only has one heater.
If you need to know I can use my clamp meter to see the amps.
The other one has two of the same model as the one I swapped today.
James
Hi James,
We just made some tests and it appears that the January production batch has the same issue that was fixed in October. (wrong component installed).
So the fix was not applied in production lines as it should be.
We will send you fixed units ASAP.
Please contact the Stelpro Customer Support for new units.
Sorry for the inconvenience.
I’ve swapped the other thermostat now too. It exhibits the same behavior.
My multi-meter reads around 16.3 A when running and .005 A when not.
If you message me your email address I could send a short audio recoding of the sound.
Two replacements came today. They’re installed and working great. 
Thanks
James
Glad to know that everything finaly works fine.
I have filed an engineering request to make sure all our current inventory is checked against the faulty component.
Hi all,
Following 2017 April’s SmartThings platform update, the Stelpro Ki Thermostat device handler stopped working properly.
A fix has been published in github.
Hi. I’m looking to pick up a few of these STZB402+ thermostats for my line voltage forced fan heaters. Reading the previous thread, it seems like there were some production issues causing fan cycling problems. Have these production issues been resolved? Anyone have any recent experiences to share?
Hi @alicchen,
Yes, the production issue has been resolved and the previously produced units have been refactored.
There are still some units that were sold to retailers that may still have the issue.
If you purchase a unit with the fan issue, we will replace it free of charge
Device Handler updated
-Setpoint circle tile removed since the information is already shown in the main tile
So I finally got around to installing these, and I think I may have some of those defective units. I get the cycling issue with my forced convection heaters and they seem to be making a clicking noise. How can I get that fixed?