Unit Operation; Vav W7100A Discharge Air; Controller (7U11) - Trane RAUJ-C20 Installation, Operation And Maintenance Manual

Figure 64. Junction box: 80-120 Ton units
HPC Wires
4S1/4S2
LPC Wires
4S3/4S4 Blu
Control Box
Connection Wires
Compr Protection
Switch Wires
4S5/4S6 Yel
Control Box
Connection Wires
Crankcase Heater
Wires
3B2HR13/3B3HR14
3B5HR16/3B6HR17
Control Box
Connection Wires
Power Wires from
Control Box

Unit Operation

VAV W7100A Discharge Air Controller
(7U11)
The discharge air controller used in Variable Air
Volume applications is a Honeywell W7100A. This
microprocessor controller is designed to maintain an
average discharge air (D/A) temperature by:
• Monitoring the discharge air temperature sensor;
and
SS-SVX11K-EN
Crankcase Heater
Wires
3B1HR12/3B4HR15
Blk
Control Box
Connection Wires
DLT Wire 4S76/4S77
Control Box Connection Wire
Power Wires from Control Box
T1
Red
T3
Compressor 1B, 2B, 1C & 2C
J-Box Shown w/o cover
T1
Red
Compressor 1A & 2A
J-Box Shown w/o cover
T2
See Detail E
Blue
• Modulating economizer dampers and sequencing
stages of mechanical cooling "On" or "Off", as
required.
The W7100A receives analog input from the discharge
air sensor mounted in the supply duct every 2 to 3
seconds by pulsing DC current across the sensor, then
"reading" the voltage potential across this thermistor.
If the comparison between the setpoint and the actual
discharge air temperature indicates that cooling is
required, the W7100A attempts to satisfy the load by
modulating the economizer open (if applicable).
O O p p e e r r a a t t i i n n g g P P r r i i n n c c i i p p l l e e s s
T2
Blue
See Detail E
Control Box
Connection Wire
DLT Wire
4S76/4S77
L2 L3
L1
L N S1 S2 M1 M2
Detail E
89