YORK INTERNATIONAL
126
FORM 100.50-NOM1 (604)
Service
CO
2
Sensor
The CO
2
sensor is used in conjunction with the
De mand
Ventilation
option. The demand for ventilation is deter-
mined by comparing the level of CO
2
in the build ing
to the
Demand Ventilation Setpoint.
The CO
2
lev el in
the building is measured by the CO
2
sensor and out puts
0 to 5 volts DC based on the level of carbon di ox ide
sensed. The unit controller then modulates the out side
air dampers to bring the level of CO
2
. Table 30 il lus -
trates the DC output for a given CO
2
level.
TABLE 30 – CO
2
SENSOR OUTPUT
combination sensor also has a tem per a ture sensor that
senses the outdoor air temperature and has the same
resistance value of a “stand-alone” out door sensor. The
resistance value for a speci
Þ
c out door temperature is
shown in Table 22. Note that the combination humidity/
temperature sensor has four ter mi nals – two for the hu-
midity sensor and two for the temperature sensor.
TABLE 29 – HU MID I TY SENSOR OUTPUT
Humidity Temperature Sensor – Outside, Return
and Underfl oor (MIT)
The humidity/temperature sensor is a combination sen-
sor that will output a 0 to 5 volt DC voltage in response
to the relative humidity sensed. The hu mid i ty sensor is
used in conjunction with the economizer function. The
HUMIDITY SENSOR OUTPUT TABLE
% RELATIVE HUMIDITY
OUTPUT VOLTAGE - VDC
% RELATIVE HUMIDITY
OUTPUT VOLTAGE - VDC
5
0.25
55
2.75
10
0.50
60
3.00
15
0.75
65
3.25
20
1.00
70
3.50
25
1.25
75
3.75
30
1.50
80
4.00
35
1.75
85
4.25
40
2.00
90
4.50
45
2.25
95
4.75
50
2.50
100
5.00
CO
2
OUTPUT TABLE
PPM CO
2
OUTPUT VOLTAGE - VDC
PPM CO
2
OUTPUT VOLTAGE - VDC
200
0.40
2800
5.60
400
0.80
3000
6.00
600
1.20
3200
6.40
800
1.60
3400
6.80
1000
2.00
3600
7.20
1200
2.40
3800
7.60
1400
2.80
4000
8.00
1600
3.20
4200
8.40
1800
3.60
4400
8.80
2000
4.00
4600
9.20
2200
4.40
4800
9.60
2400
4.80
5000
10.00
2600
5.20