229
JOHNSON CONTROLS
5276178-JIM-C-0118
8
TABLE 95 - DUCT PRESSURE TRANSDUCER
1.25" WC SPAN
DIFFERENTIAL
INPUT PRESS
2.5" WC SPAN
DIFFERENTIAL
INPUT PRESS
5.0" WC SPAN
DIFFERENTIAL
INPUT PRESS
VOLTAGE
VDC
0.125
0.25
0.5
0.50
0.25
0.50
1.0
1.00
0.375
0.75
1.50
1.50
0.50
1.00
2.00
2.00
0.625
1.25
2.50
2.50
0.75
1.50
3.00
3.00
0.875
1.75
3.50
3.50
1.00
2.00
4.00
4.00
1.125
2.25
4.50
4.50
1.25
2.50
5.00
5.00
Building Pressure Transducer
The Building Pressure Transducer is located in the
supply air section of the unit. The purpose of the
transducer is to sense and convert the static pressure in
the building to a 0 to 5VDC voltage. The DC voltage
is then sent to the Unit Controller and compared against
the
“BUILDING PRESSURE ACTIVE SETPOINT”
.
The transducer is factory wired, but pneumatic tubing
must be field supplied and installed
(refer to Section 2
“Installation” in this manual).
The Building Pressure
Transducer measures differential pressure in the
building and atmospheric pressure. When verifying
transducer operation, the technician can insert a tee
into the pneumatic tubing and connect a manometer
to the tee to verify the pressure being applied to the
transducer. Once this pressure is known, a comparison
can be made of the building pressure vs. output VDC
from the transducer. A practical and quick check of
this transducer can also be accomplished by removing
the pneumatic tubing lines from both the low and high
side connections on the transducer. Since both of the
inputs will now be exposed to the same pressure, the
differential pressure will be zero, and the output 2.5VDC
according to Table86.
TABLE 96 - BUILDING PRESSURE
TRANSDUCER OUTPUT
DIFFERENTIAL INPUT
PRESSURE - IWC
OUPTUT VOLTAGE - VDC
-0.50
0.00
-0.40
0.50
-0.30
1.00
-0.20
1.50
-0.10
2.00
0.00
2.50
0.10
3.00
0.20
3.50
0.30
4.00
0.40
4.50
0.50
5.00
Humidity Sensors
The humidity sensor outputs a 0 to 5VDC in response to
the relative humidity sensed. An outdoor air humidity
sensor is used whenever the economizer is configured
for single or dual enthalpy. A return air humidity sensor
is used whenever the economizer is configured for dual
enthalpy. A humidity sensor is also used to monitor the
humidity in the space between the slab and raised floor
system used for FlexSys applications. Table 87 gives the
relationship between the voltage output of the humidity
sensor and the % relative humidity.
TABLE 97 - HUMIDITY SENSOR OUTPUTS
%
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
Содержание 40 25 TON
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