Wifi Thermostat Compatibility

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Old 01-19-20, 12:42 PM
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Angry Wifi Thermostat Compatibility

Very frustrated with wiFi thermostat wiring. A few years ago I replaced a Honeywell RTH2300B with a Honeywell RTH9580WF. Used the existing red and white wires coming out of the wall and ran a new c-wire to the furnace. All worked well for a few days until one morning we woke up and the heat was not on. Thermostat called for heat, furnace would not fire. I thought there was an issue with the furnace, so I called a service technician. He said to scrap the wifi thermostat. We did just that and heat worked fine.
Fast forward to last week, I replaced my Aprilaire 600 humidifier/humidistat with a new one (old one was 25 years old). Ran all new wires to thermostat/humidistat and wired it per the wiring instructions. Again, it all worked fine for a few days and then one night the furnace would not fire...here we go again! At one point the screen of the RTH2300B went blank and I had to reset everything (batteries are new). I swapped the RTH2300B with a Honeywell RTH8580WF that I had. Worked for a few hours but then furnace did not fire again. Toyed with it for hours! Noticed that when I manually turn it off and then on, the furnace fires, but when the thermostat itself calls for heat it would not fire. I then decided to reinstall the RTH2300B to the old red and white wires. All is fine now that the old TS and old wires are connected.
I have a 25 year old Rheem Criterion II furnace and it has two zones. Not sure if the zoning has anything to do with it. Is it possible I need to also have a wifi TS on the second zone too? If I am leaving out any pertinent information I apologize.
 
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Old 01-19-20, 08:29 PM
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Do you get any error codes at the furnace when this problems occurs?
This sounds more like a furnace issue. I would expect pressure switch or flame sensor issues.
 
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Old 01-19-20, 09:09 PM
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Sounds like an old system with a zoning board.
Most old zoning boards are particular to thermostat type.
 
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Old 01-20-20, 07:30 AM
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I just reinstalled the wifi stat and it's functioning okay right now. Will wait for it to stop working then will check error code. The panel on the furnace does not have a window so I need to take off the panel to check. Will this reset the error code when I remove the panel?
FYI, the original TS wiring goes to the furnace panel (R and W) and then that wire goes to the damper control box. Wires split off to the two TSs from there. I also attached the furnace wiring diagram if that helps at all. I will plan to email Rheem to see if there is a known compatibility issue.
Thank you!
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Old 01-20-20, 01:58 PM
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It just stopped working and I checked the furnace. The PWR is solid green, the OK blinks once followed by a pause. I understand this to mean a "1-hour lockout". Why would this happen only with the smart stats?
 
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Old 01-20-20, 08:01 PM
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What zone board are you using and what do the lights show on it?
 
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Old 01-21-20, 03:50 AM
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There is no zone board, the stats are just wired to the Honeywell damper motor actuator.
 
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Old 01-21-20, 11:27 AM
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Curious of how thermostats are wired to the dampers and then dampers to furnace. Could be dampers aren't fully opening but still triggering furnace which then overheats causing lockout. Or not opening at all so not calling furnace.

What model dampers? Can you post a picture of how they are wired? Is there a separate transformer for them?
 
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Old 01-21-20, 06:19 PM
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It is truly spaghetti wiring but what I can tell it is wired the way I drew it up. If it does not make sense maybe I did not follow the wires properly but I'm pretty sure I got it correct. The damper is a Honeywell M835A and all it does is rotate the damper flap inside the unit. It's wired to the furnace and what looks like a transformer.
BTW, when I came home today furnace was in the lockout mode. Funny thing is, the old stat is connected, not the smart stat.
 
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Old 01-21-20, 06:23 PM
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I tried to post more pics but it says the size limit has been exceeded.
 
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Old 01-21-20, 07:15 PM
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Each member gets 10Mb of picture storage. Your last two pictures are 5Mb alone. So you've pretty much used up your space. I can go thru and resize your pictures but the board is currently under "update" and many moderator functions are not working correctly.

A damper needs a bit of logic to work correctly. Looking at your wiring..... if stat two calls for heat..... the damper opens and the two blue wires close. That will make the furnace light but will kill any power to stat one unless you are using dedicated C connections.
 
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Old 01-21-20, 07:54 PM
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I must have the stats mixed up on my diagram. Currently the main stat is the one that controls and the second one doesn't get the heat until the main one finishes heating. Sorry about the pic sizes, I'm new to the forum.

Do you think my problems are related to the install of the new humidistat? Ever since I replaced my Aprilaire 600, that's when the problems started. I wired it exactly as Aprilaire instructed.

My problem seems to have shifted from why doesn't my wifi stat work to why does my furnace keep going into lockout.
 
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Old 01-21-20, 08:21 PM
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Can you drive that damper open and close to verify that it works?
 
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Old 01-21-20, 08:36 PM
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https://customer.honeywell.com/resou...0s/71-3201.pdf

It looks like the damper will only open if zone 2 has a demand. I would measure the heat rise across the furnace with only zone 1 calling for heat. I would then give zone 2 a heating demand with no demand for heat on zone 1 and measure the heat rise across the furnace and verify that the damper opens. The third test would be to give both zones a heating demand and verify that the damper opens and that the stats do not blank out.

The maximum heat rise will be listed on the furnace nomenclature. I would expect it to say a 30 to 60 degree rise is the desired range.
 
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Old 01-22-20, 12:10 AM
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If the damper is running on a separate transformer you want zone 2 stat common to connect to the damper transformer and zone 1 common to connect to the furnace transformer.
 
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Old 01-23-20, 09:09 AM
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Houston204, thank you very much for the schematic! My damper is actually working fine and I think my thread has gone astray. My initial issue is with the compatibility of the wifi stats which is why the wiring of the stats to the damper was brought up. However, since I have other issues with my heat at the moment I am abandoning my use of the wifi stats for now until my other issues are figured out.

Thank you everyone. I will start a new thread with my other issues.
 
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