topic Re: how connect aprilaire model 700 humidifier in Nest Thermostats

how connect aprilaire model 700 humidifier

rgaila — Wed, 08 Sep 2021 16:24:21 GMT

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Original Poster: Pat&Kitty Shirk

need to know how to wire and control aprilaire model 700 with nest gen 3 thermostat

Re: how connect aprilaire model 700 humidifier

BatraD — Thu, 23 Dec 2021 11:56:51 GMT

I have the same issue. Have the * wire going to one leg of the April air and second going to C wire in the board. Nest Gen 3 keeps giving an error message and won’t operate.
please help

Re: how connect aprilaire model 700 humidifier

Jake — Tue, 18 Jan 2022 22:00:02 GMT

Hey BatraD,

Sorry for the late reply. I wanted to follow up and ensure you are good to go. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.

Best regards,
Jake

Re: how connect aprilaire model 700 humidifier

mth2000 — Mon, 14 Feb 2022 15:46:08 GMT

Jake, I have the same issue with an AprileAire 700 humidifier with the Nest Gen 3 thermostat. All the documentation I have read indicates that the * and c will provide 24VAC to the humidifier to start it right up. However, it doesn't work. I measure 19VAC between * and c when the thermostat is calling for humidity. I measure 14VAC when it's not. I tried to install a relay but that doesn't work either. It appears the * has almost no current to drive any load. When I connect 24VAC from a transformer to the Aprilaire, it starts up without any issues. I have also tried a different nest from somewhere else in the house in its place and get the exact same issue. I am thinking this is a nest design problem? I am at my wits end and looking for any help.