Nest and Honeywell DR65 Wiring

Hi,

I have a Bryant furnace with a Gen2 Nest. It works perfectly. I just added a Honeywell DR65 dehumidifier to the furnace. The installer could not get the Nest to control the dehumidifier, so he added a second t-stat (A Honeywell Digital TrueIAQ) to control the dehumidification and the Nest controls the heat. I do not have AC. Any suggestions on how I could get the Nest to work with the furnace and dehumidifier and eliminate the need for the TrueIAQ? I called Nest and they said that the DR65 was incompatible with the Nest and this was the installer's only way of getting it to work. Thanks. Chris

 

The TrueIAQ is a far better control for your DR65, and you are best to leave it on that than hooking it up to the Nest.

 

Ok, thanks for the response. That said, I have a few questions about that t-stat:

I have a new house and for some reason the Window Frost setting has been coming on at random times and running for hours on end. I have tried different frost settings to no avail. I never have frost or condensation on the windows and do not have the outdoor sensor connected.

Also, can I program the thermostat to dehumidify and come on or off based on a programmed time of day? There does not seem to be a programmable time function, even in the advanced controls.

Is there a better tstat out there for me given my current configuration and requirements?

Thanks - Chris

 

The frost setting is for the humidifier mode, and do you have a humidifier on your system?

If you don't then go into advanced setting and set #15 set to off.

THere is no program for dehumidify, and why would you want that? I think having it controling comfort 24/7.

There's Honeywell IAQ t-stat that can control things from the t-stat.

 

I do not have a humidifier. The dehumidifier is in a basement and it can get a little stuffy down there. Since the Nest Gen 2 does not have an programmable fan only, I would like the dehumidifier tstat to be programmed to come on for an hour or so each day to circulate the air. Any advice on how I can make that happen? Or another stat? Maybe I just get rid of the nest for the basement and get a stat that can control the heat and dehumidifier? Thoughts?

Thanks for the frost protection advice. It was set to "0" not installed, so it kept coming on. Once it was set to "1" FP Off, it deactivated it.

Thanks,
Chris

 

Do you know if the dealer has wired the TrueIAQ to the furance's G wire?

 

So, I opened up the IAQ stat cover and found six wires connected. Red, Common (blue), white, green, yellow to dehumid and brown to dehumid. I then opened up the furnace and found all those wires spliced in a bunch running into the dehumidifier, furnace and Nest wires...

The tstat wire does not go into the G wire on the furnace though there is a G wire connected from the furnace to the Zone board. This particular furnace runs two zones.

What do you think? Thanks very much!

 

The colors don't mean anything, but what they are connected to there.. But since you said G wasn't tied to it, then the blower is not doing anything.

But you can program the TrueIAQ to turn on the fan when the dehumidifier comes on, and it needs to be wired up.

 

I can confirm that the system and the tstat work properly. The furnace blower comes on when dehumid is called for. What I would really like is for the Nest to have a programmable fan only function? Or to have a tstat that will be programmable (time on off setting) that will work with my config. Thoughts?

Thanks,
Chris

 

Oh ok.

If you did the Honeywell IAQ lines, then yes, you can program the fan to run on a schedule.

 

Could I just leave the Nest as is, and replace the TrueIAQ with a programmable IAQ? Would I wire it the same way as the TrueIAQ (as mentioned above)? Which IAQ would you recommend to work with the DR65 combined with the Nest? Thanks.

 

No, you won't be able to leave the Nest, there will be conflex in the wiring and you can get wifi on the IAQ models.

 

Sorry, poor choice of words. If I keep the Nest and want to swap out the TrueIAQ for an IAQ programmable, wifi model, would I need to change the current wiring setup to a "new" IAQ tstat? Or would I just wire it exactly the same?

Thanks.

 

You'll have some wire changes, and all the wire will be tied to the EIM near the furnace vs up at the t-stat itself.

We can help you with the hook up if youget one.

 

Thank you. I will keep you posted.

 

One more quick question...after all my fiddling around with the stat, I now have a humidifier (auto off) option setting on the TrueIAQ along with the dehumidifier (auto off) setting. Is there any way to remove that humidifier setting, since I don't have a humidifier? Thanks.

 

No, there's no way to "shut off" the humidifier part of the TrueIAQ..