Monday, 19 April 2021

Setting up dehumidifier mode for Bryant FV4C fan coil Nest learning thermostat

I have a Carrier/Bryant FV4C variable speed air handler that has its own Dehumidifier mode. I try to set it up with the Nest but I am not sure which setting on the Nest should I choose. Here is what I did:

On the air handler control board, remove the J1 jumper between the R and DH (dehumidifier) terminal.
Connect a wire to the DH terminal, and the other end of the wire to the * (star) terminal on the Nest.
The on Nest setup, choose Dehumidifier for *, and choose "Dehumidify with AC". And then is the question:

Nest ask To dehumidify, energize or de-energize the * terminal. From the air handler manual, when dehumidification is needed, thermostat would open circuit R to DH, to reduce fan speed. It seems like I should choose "de-energize the * terminal". And that means if no dehumidification is needed, the * terminal should be closed (energized). Could someone with experience confirm that?

Another selection is when dehumidification is called, system should "Activate fan" or "Not". I chose "Not" because AC should turn on the fan itself.

Appreciate if someone with experience could provide some insight.


source https://hvac-talk.com/vbb/threads/2228326-Setting-up-dehumidifier-mode-for-Bryant-FV4C-fan-coil-Nest-learning-thermostat?goto=newpost

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