![background image](http://html1.mh-extra.com/html/carrier/50lc-07/50lc-07_service-and-maintenance-instructions_2561600050.webp)
50
Hardware
Actuators —
The Economizer X damper actuators are direct--coupled
types with spring--return. Power is 24--v from the W7220
outputs. Range of rotation is 95--degrees; timing for
full--range movement is 90 seconds to drive open in
normal operation, 30 seconds in Test Mode and 25
seconds for spring return.
These actuators are S--bus enabled. The S--bus is a
proprietary local equipment network that connects the
W7220 controller, one S--enabled actuator and up to three
S--type enthalpy sensors on a two--wire communication
network. The S--bus is polarity--insensitive. Devices
attached to the S-- bus are automatically recognized by the
controller.
Actuator command position is defined in a 2--10 vdc
value. 2.0--v is outside air damper position fully--closed
(0% open); 10.0--v is damper position fully--open (100%
open). See Table 13 to correlate control voltage values to
outside air damper opening percentage.
Table 13 – Actuator Voltage vs. Damper Position
Vdc
% Open
Vdc
% Open
Vdc
% Open
2.0
0
4.8
35
7.6
70
2.4
5
5.2
40
8.0
75
2.8
10
5.6
45
8.4
80
3.2
15
6.0
50
8.8
85
3.6
20
6.4
55
9.2
90
4.0
25
6.8
60
9.6
95
4.4
30
7.2
65
10.0
100
These units use a 3--Nm (27 lb--in) torque model,
Honeywell Series MS3103K actuator.
Supply Air Temperature Sensor —
The W7220 controller uses a 20--k ohm analog sensor for
Supply Air Temperature (SAT). The thermistor is attached
to a ring terminal. The ring terminal is attached to the
unit’s supply fan housing, downstream of the unit’s indoor
coil. The SAT sensor is connected to the W7220 input
terminals marked MAT. See Table 14 for sensor resistance
to temperature correlations.
The W7220 controller requires a valid signal from its SAT
channel in order to function. If the SAT connection to the
W7220 is lost, the W7220 will initiate an alarm condition
immediately. No economizing operation will be permitted
until this alarm is cleared.
Table 14 – SAT/OAT Sensor Characteristics
Deg C
Ohms
Deg F
Ohms
---30
415156
---20
386130
---25
301540
0
193070
---20
221210
20
101820
---15
163834
32
70200
---10
122453
40
55420
---5
92382
45
47771
0
70200
50
41258
5
53806
55
35725
10
41561
60
31035
15
32341
65
27069
20
25346
70
23719
25
20000
77
20000
30
15886
80
18473
35
12698
100
11544
40
10212
120
6768
45
8261
50
6720
Outside Air Temperature Sensor —
Economizer X systems equipped with outdoor dry bulb
temperature changeover control include a 20--k ohm
analog sensor to measure Outdoor Air Temperature
(OAT). This is the same sensor used for the SAT function;
see Table 14 for resistance vs temperature characteristics.
The OAT sensor is attached to the outside air damper frame.
It is connected to the W7220’s OAT input terminals.
If an accessory enthalpy sensor is added to an Economizer X
system with factory dry bulb changeover, disconnect this
OAT sensor wiring at the W7220’s OAT input terminals.
Enthalpy Control Sensor Configuration—
The W7220 economizer control system can accommodate
up to three S--bus enthalpy sensors. On Economizer X
models with factory--installed Enthalpy Changeover
control, one S--bus sensor is provided in the economizer
outdoor section. Additional sensors may be added to
measure Return Air and Discharge Air conditions.
The Enthalpy Control sensor (Part Number: HH57AC081)
communicates with the W7220 Economizer controller on the
two--wire local equipment network bus (S--bus) and can
either be wired using a two pin header or using a side
connector. This sensor is used for all OAT (Outdoor Air
Temperature), RAT (Return Air Temperature) and DAT
(Discharge Air Temperature), depending on how its three
position DIP switch is set.
Use Fig. 61 and Table 15 to locate the wiring terminals for
each Enthalpy Control sensor.
Use Fig. 61 and Table 16 to set the DIP switches for the
desired use (location) of the sensor.
Summary of Contents for 50LC 07
Page 9: ...9 COOLING CHARGING CHARTS C150169 Fig 9 Cooling Charging Charts 07 ...
Page 10: ...10 COOLING CHARGING CHARTS C150172 Fig 10 Cooling Charging Charts 08 ...
Page 11: ...11 COOLING CHARGING CHARTS C150170 Fig 11 Cooling Charging Charts 09 ...
Page 12: ...12 COOLING CHARGING CHARTS C150171 Fig 12 Cooling Charging Charts 12 ...
Page 27: ...27 C150181 Fig 34 50LC 07 Control Wiring Diagram ...
Page 28: ...28 C150225 Fig 35 50LC 07 RTU Open Control Wiring Diagram ...
Page 29: ...29 C14095 Fig 36 50LC 07 Power Wiring Diagram 208 230V 460V and 575V Units ...
Page 30: ...30 C14013 Fig 37 50LC 08 12 Control Wiring Diagram ...
Page 31: ...31 C14104 Fig 38 50LC 08 12 RTU Open Control Wiring Diagram ...
Page 32: ...32 C14105 Fig 39 50LC 08 12 Power Wiring Diagram 208 230V Units ...
Page 33: ...33 C150216 Fig 40 50LC 08 12 Power Wiring Diagram 460V 575V Units ...
Page 57: ...57 C13683 Fig 62 Typical EconoMi er X Wiring Diagram ...