Nest 2.0 & Honeywell HE250A
#1
12-16-12, 09:34 AM
Nest 2.0 & Honeywell HE250A
Hi, I'm trying to determine the proper way to hook up my Nest 2.0 to my Honeywell HE250A. Currently the HE250A is conected to a Honeywell Humidistat mounted on my duct. I understand I need to bypass the Humidistat... My HVAC guy stopped by for my annual service and I asked him about hooking it up. He said it's easy to do, handed me a White Rogers 90-380 relay and said run 2 wires to the Nest and the other 2 to the "HUM" control on the HE250A and you're done. I have no idea based upon the relay he gave me where to begin. Any help is appreciated!
#2
12-16-12, 01:35 PM
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If you want to use the relay, then you wire that in place of the humidistat, then wire the coil side to Nest's * and C at the furnace.
Or redo the wires, and wire the Nest right to the humidifier itself, and no relay needed.
Or redo the wires, and wire the Nest right to the humidifier itself, and no relay needed.
#4
12-16-12, 06:22 PM
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No, you will have to rewire it if you don't want to use the relay. You will undo the wire that is on the current t-stat since you are not using that power.
#5
01-06-13, 04:59 AM
Update
I had some time to look deeper at this.... On my humidifier there are two wires at the "hum control" that go to the humidistat. There is also a block inside the humidifier labeled "equip" which has GR and R that go into the furnace. Finally there is a 24v power block that also goes into the furnace.
Given this scenario, is there a different recommended way to hook up the nest?
Thanks!
Given this scenario, is there a different recommended way to hook up the nest?
Thanks!
#6
01-06-13, 06:23 AM
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Ok, I found the diagram for this unit, and it's a newer model that I have not see in person.
You will need the relay for this.
So you wire the relay between the Nest * and C at the furnace.
Then the contact side of the relay, you will wire the HUM to it.
You will need the relay for this.
So you wire the relay between the Nest * and C at the furnace.
Then the contact side of the relay, you will wire the HUM to it.
#7
01-26-13, 05:11 AM
Since the humidifier is already connected and fully functional (comes on independent of heat) does this change the config? The humidifier is already connected to "c" on furnace.
#10
01-26-13, 06:43 AM
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You should have C and R from "Power" side of it to the furnace, and on the "Equipment" 'side there W and C also should be going to the furnace.
The relay coil side should be * and C. Relay contact side wired to "HUM/Control" on the humidifier
Dip switch on humidifier set "Monitor system" to on, and "call for fan" to off.
The relay coil side should be * and C. Relay contact side wired to "HUM/Control" on the humidifier
Dip switch on humidifier set "Monitor system" to on, and "call for fan" to off.
