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130 RT-SVD03L-EN
depending on model, or the right side beneath the
control panel on Voyager
™
Light Commercial, or the
economizer end of unit for Voyager ™ Commercial
units. Ventilation holes in the access panel of the unit
allow air movement across the sensor. The OAS
connects to the RTRM module.
Figure 78. Outdoor air sensor
Outdoor Air Sensor
Outdoor Humidity Sensor (OHS)
The OHS measures the relative humidity of the outside
air. It is located inside the economizer hood. The OHS
is plugged into the ECA.
Return Air Temperature Sensor (RAT)
The RAT measures the return air temperature. It is
located on the return air damper of the economizer.
The RAT is plugged into the ECA.
Return Humidity Sensor (RHS)
The RHS measures the relative humidity of the return
air. It is located on the return air damper of the
economizer. The RHS is plugged into the ECA.
Economizer Damper Enthalpy Layout
Table 92. Choice of enthalpy method
Method used to determine
economizer effectiveness
Required Data
Comparative Enthalpy
MAS, OAT, OAH, RAT,
RAH
Reference Enthalpy MAS, OAT, OAH
Reference Dry Bulb MAS, OAT
Unit will not economize
MAS or OAT data is
invalid or unavailable
Figure 79. Economizer - sensors location
Return Air Humidity Sensor
Return Air Temp Sensor
Outside Air Humidity Sensor
Economizer Operation Enthalpy
Changeover
Dry Bulb/Reference Point Selections
The dry bulb or reference enthalpy point is user-
selectable, according to the choices below. This
selection is made on the ECA.
Table 93. Potentiometer settings
Potentiometer
Setting Point
Dry bulb
changeover
Point
Reference
Enthalpy
A 73°F 27 BTU/lb.
B 70°F
25 BTU/lb.
C
(a) 67°F
23 BTU/lb.
D 63°F
22 BTU/lb.
E 55ºF
19 BTU/lb.
(a) Factory setting
Comparative Enthalpy Method
OA enthalpy is compared with RA enthalpy.
• The economizer is enabled when OA Enthalpy < [RA
Enthalpy - 3.0 BTU/lb.]
• The economizer is disabled when OA Enthalpy > RA
Enthalpy.
• While [RA Enthalpy - 3.0 BTU/lb.] < OA Enthalpy <
RA Enthalpy, the economizer enable/disable status
is not changed.
E Ecco on no om miizze err