95
JOHNSON CONTROLS
FORM 145.05-NOM2 (807)
ANALOG INPUTS
Temperature Sensors
The temperature sensors are all 10K Type II thermistors.
The relationship between the temperature and the
resistance is contained in Table 17. The following
analog outputs are of this type:
•
Supply Air Temperature
•
Return Air Temperature
•
Mixed Air Temperature
•
Slab Temperature
•
In Water Temperature
•
Out Water Temperature
•
Outdoor Air Temperature
•
Coil Leaving Temperature.
TABLE 17 – TEMPERATURE SENSOR
RESISTANCE
° F
RESISTANCE
(OHMS)
° F
RESISTANCE
(OHMS)
-25
196,300
60
15,310
-20
165,100
65
13,480
-15
139,300
70
11,880
-10
118,000
75
10,500
-5
100,200
80
9,298
0
85,350
85
8,250
5
72,910
90
7,331
10
62,480
95
6,532
15
53,640
100
5,826
20
46,230
105
5,209
25
39,910
110
4,663
30
34,560
115
4,182
35
30,000
120
3,757
40
26,100
125
3,381
45
27,760
130
3,047
50
19,900
135
2,750
55
17,440
140
2,486
Duct Pressure Transducer
A duct pressure transducer is located in a control box
to the left hand side of the main control enclosure on
two compressor units and to the right hand side of the
main control enclosure on 4 compressor units. There
may be one or two transducers depending on how the
unit was ordered. The purpose of the transducer is to
sense and convert the static pressure in the supply-side
duct work or the under fl oor space and convert it to a 4
– 20 ma input. The milliamp input is sent to the Unit
Control and compared against the “Fan-S/A Pres SP”.
The transducer(s) are factory wired, but the pneumatic
tubing must be fi eld supplied and installed
(refer to
Section 2 “Installation” in this manual).
On VAV units
the duct static pressure transducer measures differential
pressure between the pressure in the duct and a reference
point, usually atmosphere. On FlexSys units the duct
static pressure transducer measures differential pressure
between the under fl oor space and a reference point.
When verifying transducer operation, the technician
must insert a tee in each of the tubes connected to the
transducer to verify the differential pressure being
applied to the transducer. Once this pressure is known,
a comparison can be made of the duct pressure vs.
output milliamp values from the transducer. To check
the milliamp output from the transducer remove the
wire from the output (S) or (OUT) connection on the
transducer and connect your meter between the end of
the wire and the (S) or (OUT) terminal of the transducer.
Table 18 (for VAV units) and Table 19 (for FlexSys
units) shows the relationship between the pressure
applied to the duct static pressure transducer and the
output voltage. The output is linear.
TABLE 18 – VAV DUCT STATIC PRESSURE
TRANSDUCER
DIFF PRESS
(IN WC)
MA
OUTPUT
DIFF PRESS
(IN WC)
MA
OUTPUT
0.0
4.0
3.0
13.6
0.5
5.6
3.5
15.2
1.0
7.2
4.0
16.8
1.5
8.8
4.5
18.4
2.0
10.4
5.0
20.0
2.5
12.0
TABLE 19 – FLEXSYS DUCT STATIC PRESSURE
TRANSDUCER
DIFF PRESS
(IN WC)
MA
OUTPUT
DIFF PRESS
(IN WC)
MA
OUTPUT
0.0
4.0
0.15
13.6
0.025
5.6
0.175
15.2
0.050
7.2
0.20
16.8
0.075
8.8
0.225
18.4
0.10
10.4
0.25
20.0
0.125
12.0
8
SECTION 8 – SERVICE
Содержание YSCD
Страница 10: ...10 JOHNSON CONTROLS FORM 145 05 NOM2 807 THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 12: ...12 JOHNSON CONTROLS FORM 145 05 NOM2 807 THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 38: ...38 JOHNSON CONTROLS FORM 145 05 NOM2 807 THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 46: ...46 JOHNSON CONTROLS FORM 145 05 NOM2 807 THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 105: ...105 JOHNSON CONTROLS FORM 145 05 NOM2 807 LD13009 8 FIG 11 WIRING DIAGRAM POWER CIRCUIT ...
Страница 106: ...106 JOHNSON CONTROLS FORM 145 05 NOM2 807 Service FIG 12 WIRING DIAGRAM MAIN CONTROL BOARD LD13010 ...
Страница 107: ...107 JOHNSON CONTROLS FORM 145 05 NOM2 807 8 FIG 13 WIRING DIAGRAM EXPANSION CONTROL BOARD LD13011 ...