Honeywell PRESTIGE THX9321 - Manual (Page 151)

THX9321 PRESTIGE ® 2.0 AND THX9421 PRESTIGE ® IAQ WITH EIM
151 68-0311—02
Economizer Module Wiring Diagrams
Typical wiring of a W7220 Economizer Module for a heat pump system, using a Prestige THX9321 thermostat or Equipment
Interface Module.
Fig. 346. Wiring a W7220 Economizer Module for a heat pump system.
Typical wiring of a W7220 Economizer Module for a conventional system, using a Prestige THX9321 thermostat or Equipment
Interface Module.
Fig. 347. Wiring a W7220 Economizer Module for a conventional system.
1 “A” or “L/A” terminal must be configured for Economizer in the installer setup (ISU 2220). These terminals are powered by the
cooling transformer (Rc terminal).
2 Terminal AUX 2 is present only on the Equipment Interface Module.
3 Connect the changeover valve from the roof top unit to the normally open contacts of an isolation relay to prevent feedback into
the economizer module during defrost. If this is not done when the system goes into defrost, it will change the economizer into
cooling mode due to the feedback and open the outside damper while in heating mode.
120
VAC
O/B Y1 Y2 AUX AUX 2 G
24
VAC
AUX2-I
OCC
E-GND
AUX1-O
Y2-I
Y2-O
Y1-I
Y1-O
C
R
Rooftop Unit
Transformer
O/B L/A Y Y2 AUX AUX 2 G
Thermostat/EIM
R
C
W7220 Economizer Module
(See wiring guidelines provided with the product)
2 1
MCR34808
3
3 1
120
VAC
Y1 Y2 W1 W2 G
24
VAC
Rooftop Unit
Transformer
A Y Y2 W W2 G
Thermostat/EIM
R
C
W7220 Economizer Module
(See wiring guidelines provided with the product)
1
MCR34810
AUX2-I
OCC
E-GND
AUX1-O
Y2-I
Y2-O
Y1-I
Y1-O
C
R