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BillyHvac
BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22472
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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Well, I purchased a Honeywell TH9320WF5003 tstat to replace

Customer Question

Well, I purchased a Honeywell TH9320WF5003 tstat to replace a TH8321R1001. Unfortunately, there are different connectors & I'm not sure how to connect it. The OB, Y and G are easy, but the new one doesn't have U1 connectors.
This is in a brand-new house w/ a Lennox gas heat/ ac system.
Submitted: 1 year ago.
Category: HVAC
Expert:  BillyHvac replied 1 year ago.

hello,

what device do you have in U1?

Customer: replied 1 year ago.
In the old tstat, there is a jumper from R to the first U1 - the lead is red. A blue lead goes to the second U1. Red is heat, blue is a/c?
Customer: replied 1 year ago.
I have a drawing of the old & new connector blocks that I have scanned..
Expert:  BillyHvac replied 1 year ago.

the U feeds power for a dehumidifier or humidifier.

The R handels 24 for heat and cool. Do you know where the blue wire goes?

Customer: replied 1 year ago.
Why are there 2 u1's? I have a picture of the connector board in the attic unit, as well as a diagram or each tstat. Is there some way to send you attachments?
Expert:  BillyHvac replied 1 year ago.

the one u is to make power available for something else.

It is the "something else" we need to know. The current thermostat does heat. cool and...either humidifier or dehumidifier.

Once I know which I can direct further...and is there an issue with the current thermostat?

Customer: replied 1 year ago.
Just saw this
Expert:  BillyHvac replied 1 year ago.

ok, here is the issue.

The new thermostat will work fine for heating and cooling...but it will not control whatever you have extra on U1.

So basically whatever the blue goes to...whether dehumidifier or humidifier..will not function.

Is there a fault with existing unit?

Customer: replied 1 year ago.
The tstat is fine, I wanted the wifi capabilities. Does this picture help?
Expert:  BillyHvac replied 1 year ago.

No it does not.

The final item is that whatever you have attached as an accessory...Which is on U1....there is no provision for that item in the new thermostat.

The new thermostat simply does not have an accesssory feature

Customer: replied 1 year ago.
OK, thanks. More wasted money...
Expert:  BillyHvac replied 1 year ago.

I am sorry, I would love to help hook it up...but the existing system simply has one too many features for the wifi you have.

I wish you the best

Billy

Customer: replied 1 year ago.
OK, thanks.
Expert:  BillyHvac replied 1 year ago.

please rate the service of the site and I will close this question. Have a great weekend

Billy

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