Honeywell THX9321R5012 Wiring - HVAC - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 01-09-2011, 04:00 PM   #1
Newbie
 
Join Date: Jan 2011
Posts: 3
Rewards Points: 10
Default

Honeywell THX9321R5012 wiring


I am replacing an older two wire t-stat with the Honeywell THX9321R5012 t-stat and can't get it to work. I tried the W & R terminals as well as the W & C terminals but no go. Just a blank display. The backplate is stamped with... will not operate without wire to C. If W & R (the two existing wires) are for the heat, and I need to run a third wire for C, what does it tie in to?

Advertisement


Last edited by sws63075; 01-09-2011 at 04:02 PM.
sws63075 is offline   Reply With Quote
Old 01-09-2011, 04:32 PM   #2
AKA HVACTECHFW
 
Join Date: Nov 2010
Location: NE Indiana
Posts: 2,365
Rewards Points: 1,094
Blog Entries: 1
Default

Honeywell THX9321R5012 wiring


c on control board in furnace. what model furnace do you have?

Advertisement

__________________
IT IS WHAT IT IS
hvactech126 is offline   Reply With Quote
Old 01-10-2011, 08:09 AM   #3
Newbie
 
Join Date: Jan 2011
Posts: 3
Rewards Points: 10
Default

Honeywell THX9321R5012 wiring


It's an old American Standard Sunbeam K-100. No control board on this one. Just two wire 24vac for the t-stat and main gas valve. Blower is large squirrel cage type.
sws63075 is offline   Reply With Quote
Old 01-10-2011, 09:45 AM   #4
AKA HVACTECHFW
 
Join Date: Nov 2010
Location: NE Indiana
Posts: 2,365
Rewards Points: 1,094
Blog Entries: 1
Default

Honeywell THX9321R5012 wiring


c will be the ground of the furnace
__________________
IT IS WHAT IT IS
hvactech126 is offline   Reply With Quote
Old 01-10-2011, 11:16 AM   #5
Member
 
Join Date: Sep 2010
Posts: 453
Rewards Points: 252
Default

Honeywell THX9321R5012 wiring


Common Wire Names:

R or RH - HEATER TRANSFORMER
W - HEATING CONTROL
G - FAN RELAY
C - 24 VAC COMMON (optional)*
Y - COOLING COMPRESSOR
RC - COOLING TRANSFORMER
O - DAMPER OR CHANGEOVER VALVE (POWERED IN COOL)
B - DAMPER OR CHANGEOVER VALVE (POWERED IN HEAT)


* The optional C-wire should be connected if available, it will extend your battery life significantly.


Alternate wire names:

Most Common Wire Names -

R NEMA power for both heat and cool (sometimes the marking will be R v )
Rc NEMA power for cool (when separate power for cool)
Rh
or 4 NEMA power for heat (when separate power for heat)
W NEMA Heat (sometimes the marking will be W h)
Y NEMA compressor (sometimes the marking will be Y c)
G NEMA fan (sometimes the marking will be G f)
C NEMA Unswitched side of transformer or Common power
O NEMA Heat pump change over powered in cool.
B NEMA Heat pump change over powered in heat.



diyorpay is offline   Reply With Quote
Old 01-10-2011, 03:24 PM   #6
Newbie
 
Join Date: Jan 2011
Posts: 3
Rewards Points: 10
Default

Honeywell THX9321R5012 wiring


Thanks!
I emailed Honeywells' customer Care Center as well as this chatroom. They replied... The thermostat requires 3 wires for the installation. You must have a wire connected to the R, W and C terminals. The C terminal has its own voltage supplied with the wire to activate the display screen, the R terminal is used for the power from the HVAC system and the W terminal is the heat relay.

If I am understanding this correctly then I need another 24vac line for C. Installing a second transformer just for screen power wouldn't be a bad idea.
Do you agree?

Advertisement

sws63075 is offline   Reply With Quote
Reply


Thread Tools
Display Modes

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Honeywell Thermostat Wiring Differences DavidHwang HVAC 16 01-28-2012 03:11 PM
Wiring a Honeywell RA89A Relay shawnmd HVAC 7 10-21-2010 07:58 PM
Honeywell Prestige HD thermostat wiring 1H/1C + Humidification System TekGamer HVAC 0 07-10-2010 12:58 AM
Wiring help - Honeywell Thermostat w/ Carrier Heat Pump Tom Williams HVAC 7 09-14-2008 08:40 AM
Trane Heat Pump tstat replacement with Honeywell prog - wiring question sep23 HVAC 2 10-20-2006 10:10 PM




Top of Page | View New Posts