Thx9321 Thermostat Wiring Diagrams Using Universal Relays To Control Heating Or Cooling - Honeywell THX9321 Prestige 2.0 Product Data

®
THX9321 PRESTIGE 2.0 AND THX9421 PRESTIGE
THX9321 Thermostat Wiring Diagrams
Using Universal Relays to Control Heating or Cooling
The THX9321 Thermostat and the EIM have universal outputs that can be configured for the following stages of heating and
cooling, based on the terminals available.
THX9321 THERMOSTAT (U1 AND U2)
• Cool Stage 3 (ISU 2080 - commercial only)
• Cool Stage 4 (ISU 2090 - commercial only)
• Conventional Heat Stage 3 (ISU 2100, 2140)
• Backup Heat Stage 2 for Heat Pumps (ISU 2170)
• Geothermal Radiant Heat (see wiring diagrams on
page 140, page 141, and page 144)
Powering universal relay with system transformer (THX9321
shown).
Transformer
120 24
VAC VAC
HEAT STAGE 3 or
COOL STAGE 3 or
3
Fig. 326. Prestige THX9321 powering universal relay with
system transformer.
1 U1/U2/U3 terminals are normally open dry contacts when set up for a stage of heating or cooling.
2 You must install a field jumper if the stage of heating or cooling is powered by system transformer. Do NOT install a field jumper
if the stage of heating has its own transformer.
3 U1/U2/U3 terminals are assigned to a stage of heating or cooling in the Installer Setup.
68-0311—02
C
R
C
Rc
COOL STAGE 4
R
2
U1
1
U1
U2
1
U2
M32952A
®
IAQ WITH EIM
FOR THX9421 WITH EIM (U1, U2, AND U3)
• Cool Stage 3 (ISU 2080 - commercial only)
• Cool Stage 4 (ISU 2090 - commercial only)
• Geothermal Radiant Heat (see wiring diagrams on
page 140, page 141, and page 144)
NOTE: The EIM has dedicated terminals for
Conventional Heat Stage 3 and
Backup Heat Stage 2 for Heat Pumps
Powering universal relay with separate heating transformer
(THX9321 shown).
Transformer
Transformer
Fig. 327. Prestige THX9321 powering universal relay with
142
120
24
C
VAC
VAC
R
2
HEAT STAGE 3
R
3
120
24
C
VAC VAC
separate heating transformer.
C
Rc
R
U1
1
U1
U2
1
U2
M32953