So, I think I found a pretty scary bug with the software on the Pearl. For me, it's not scary right now because I have the thermostat in a garage, and only have the need to turn on the heat occasionally.
Currently, it's 26F in my garage according to 2 other temp sensors. The Pearl says 45F on the screen when it's off, which is not accurate. When I turn it to heat, it's set to 68F, but the garage heater never turns on. Here's what I see in my HE:
The thermostat thinks it's 175.8F in the garage, which is higher than the set point, so it never calls for heat. Note this this behavior is the same whether or not the thermostat is paired with the HE. And, this is a brand new thermostat that they RMA'd for me when the first one was doing the same thing. I have tried resetting to factory defaults and changing many other settings on the thermostat.
When the temp gets too low, the thermostat is incapable of calling for heat because for some reason it thinks the temperature is really high already. Imagine if you had this in your house and the power went out when you were on vacation or traveling for some other reason. When the power came back on, the thermostat may be incapable of starting the furnace if the temp got too low, and you may come home to a flooded house because of burst pipes. Ever seen what 500,000 gallons of water does to a house over 2 days? I have. 5 years later that house is still not livable because insurance companies are terrible when it comes to water damage.
If any of you in a cold area with a Pearl are planning on taking a vacation soon, I would highly recommend swapping out the Pearl with another thermostat while you are gone, at least until they can address this issue. Frankly, I'm not even sure how one would flash new firmware to this thing, I didn't see any kind of data ports on it.
I have the Pearl but don't see these issues. The battery shows -180. Is the thermostat powered by the C wire? Try removing batteries and just powered by the wiring if that is the case.
I don't have a Pearl, so I cannot comment on the specifics here. But I would strongly recommend that any battery-powered thermostat should be installed in parallel with a simple mechanical thermostat that stays close to the furnace/air-handler.
While a bimetallic strip can fail, the odds of both batteries and a bimetallic strip failing are small.
I am powering mine with the C-wire, no batteries, which is why the battery shows -180. However, I have tried putting batteries in it, and running with both the c-wire and the batteries. And also disconnecting the c-wire and only running on batteries.
I have opened a ticket with Centralite and they are going to try to reproduce the issue.
I've seen this before.... The driver is converting the temperature reported by the thermostat (apparently 79.9) from Celsius (which almost all thermostats use as the native temperature scale) to Fahrenheit (which is 175.8).
This can be caused by the thermostat reporting in degrees F instead of degrees C, and the driver doing the conversion when it's not needed... OR... With the thermostat displaying 45F on the display, it could be that the thermostat is defective...
As there doesn't seem to be a custom driver for this thermostat... Do some basic troubleshhoting...
Start by power cycling the thermostat... Remove the batteries and the C wire (if used)... Allow the device to sit for several minutes... then reinstall the batteries and C wire (if used)...
If that makes no difference... Check the setup options on the thermostat... there may be an option for the display temperature scale and the reporting temperature scale... make sure they are set correctly...
If it's still not working... you may need to do a hard reset (factory reset) on the device and reconnect it to the HE...
Then... if it still doesn't work properly, maybe contact support to ask about the issue with the generic zigbee thermostat driver...
EDIT: re-reading you initial post... This is an RMA'd device... Many manufacturers (espcially Nortek - who own centralite) do not typically provide factory new units under RMA... They provide repaired or refurbished units... Your replacement unit may be defective right out of the box...
Opps... You are right... EZLo bought Centralite... Nortek has 25% of Vera... Before EZLo bought out Vera... It's a tangled web... and hard to keep straight...
EZLo could well be in the same league....
My statement still stands... the RMA'd unit could well be DOA...
Just a thought here. No doubt there is a firmware shortfall in your Pearl and likely in mine as well.
But just for curiosity sake, what do you have for settings on the minimum heating temp and maximum heating temp. (This would be in the Pearl pia keypad setup).
BTW I'm assuming this has nothing to do with HE and the issue is with the basic thermostat operation. Is this correct?
Yes, should have nothing to do with the HE, as the problem still occurs even if I unpair it from zigbee and factory reset the unit. The HE was just letting me see what the thermostat was reporting for current temp in F.
Here's something interesting though. It defaults to F. I set it to C, and the temp display now says 81 degrees with the thermostat off. And the HE is seeing it as 178.5F right now (which happens to be 81C). So, the thermostat definitely seems to be defective. It's definitely not 81C in my garage, it's about -3C.
Also something I noticed... I tried to set the minimum heat set point lower, but 44F is the lowest you can set it to.
Maybe the temp sensor in the thermostat can't handle freezing temps? Or, more likely is that their temperature conversion algorithm is flawed, or using an unsigned float when it should be using a signed one?
I'm trying to think of a flawed conversion scenario where 46.5F (from the display) could equal 81C when switching the display to C.
It maybe out of the operational range the manufacturer designed it to be used. (rightly or wrongly) This to me would be a poor design decision.
I remember seeing some people testing Iris contact sensors to be used to monitor/freezers and having bizarre readings when reaching near freezing temps, consistent with your unsigned float theory. Same problem with some electric meat smokers (Masterbuilt in particular) that error out on startup. Some users actually use hair driers to warm them up so they will start.
Or, maybe your garage is at +178 and you didn't notice!
My Iris motion sensors reliably read temps down to -30F, I have one in a really cold freezer.
As for the thermostat, UL listing requires a very specific set of things that they need to test/support. I would guess that one of them is the ability to call for heat at any temperature. I don't know if this thermostat is UL listed though.
I seem to recall the tests were Iris V1 contacts and there were variations based on software rev.
Anyway this doesn't fix your problem, just an observation.
