How to upgrade Honeywell TH921C1004 to wifi thermostat

Reply

  #1  
Old 06-29-15, 08:28 AM
Member
Thread Starter
Join Date: Jun 2015
Location: USA
Posts: 2
Upvotes: 0
Received 0 Votes on 0 Posts
How to upgrade Honeywell TH921C1004 to wifi thermostat

Hi,

I am in a process of upgrading my thermostat to a wifi thermostat, I tried to replace my current thermostat ( Honeywell TH9421C1004) with sensi wifi thermostat but the sensi doesn't seem to be compatible with my thermostat.

My current thermostat doesn't have any color codes instead it has 1,2,3.

Do you guys know any wifi thermostat compatible with this? Please find the thermostat picture attached.
 
Attached Images  
Sponsored Links
  #2  
Old 06-29-15, 07:34 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,370
Received 10 Votes on 8 Posts
http://www.amazon.com/gp/product/B00..._dp_o_pd_S_ttl


The Honeywell Prestige IAQ is a very close match to your Honeywell IAQ.

The old one has 3 wires but you only need to connect 2 wires between the new thermostat and the New EIM.

Your existing thermostat is connected to an equipment interface module.
The new stat will have a slightly different module.
 
  #3  
Old 06-30-15, 07:38 AM
Member
Thread Starter
Join Date: Jun 2015
Location: USA
Posts: 2
Upvotes: 0
Received 0 Votes on 0 Posts
Thanks Houston204, you are awesome!!!.. I just got a response from Honeywell and they also recommended the same.

Looks like i need to replace Interface module to get the wifi thermostat, seems to be lot of things to change.

Here is Honeywell response:

Thank you for contacting Honeywell.

Please note that the TH9421C thermostat is a VisionPRO IAQ thermostat. This thermostat gets connected to the Heating and Cooling system through an Interface model. Hence this thermostat cannot be replaced with any thermostat. It may be replaced by the same unit. If you want another thermostat, you may consider getting a Redlink thermostat like THX9421R thermostat.
However, do consider that the thermostat is a professionally installed product and for a suitable recommendation we would suggest you get in touch with the installer or contact your nearest HVAC contractor for the same.

For assistance finding a contractor near you, please use the following link:
http://yourhome.honeywell.com/home/A...hereToBuy.aspx
 
  #4  
Old 06-30-15, 04:20 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,370
Received 10 Votes on 8 Posts
I recommend entering the configuration menu on your existing thermostat to see the current settings.
(Especially system type and possibly reversing valve heat or cool)

The old stat uses a code book (like function 174=7) and the new stat uses English (like system type= heat pump).
 
  #5  
Old 06-30-15, 04:37 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,370
Received 10 Votes on 8 Posts
The Prestige IAQ module looks very much like the old IAQ module.

Swapping it out is not a difficult task.

This is an example of the VisionPro IAQ in a heat pump application...



This is an example of the new Prestige IAQ with a 2 stage gas furnace and a 2 stage condenser outside...



This example also has 2 duct sensors and a float switch.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: