Section 8 – service, Analog input operation, Temperature sensors – York ECO2 YPAL 050 User Manual

Page 153: Duct pressure transducer

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153

JOHNSON CONTROLS

FORM 100.50-NOM6 (1207)

8

ANALOG INPUT OPERATION

This section describes the control operation of the (29)
twenty-nine analog inputs. These inputs are used by
the control to monitor and respond to unit temperatures,
pressures, enthalpy, etc. The location of each of these
connections on the Unit Controller is contained in
Table 8-8. Notice that the ID gives the jack connection
designated as “J” and then the identifying number of
the connector, followed by a – and then the pin number
of the connector. For example the SUPPLY AIR
TEMPERATURE analog input would be found at J1-1.
This is connector J1 – Pin 1. As the Unit Control board
is positioned in the control box the top row of the J series
connectors is the input, the middle row is the common,
and the bottom row is the 5 VDC input to the sensor.
Also the pin in the right hand top corner is pin 1.

Temperature Sensors

The temperature sensors are all 10K Type III Thermistors.
The relationship between the temperature and the
voltage output and resistance is contained in Table 8-1
.The following analog input are of this type: Supply
Air Temperature, Heat Entering Temp, Flex Evap Temp,
Outside Air Temp, Return Air Temp, Suction Temp #1,
Suction Temp #2, Zone Temp, and Under Floor Temp.

Duct Pressure Transducer

The Duct Pressure Transducer is located behind the right
hand damper door. The purpose of the transducer is to
sense and convert the static pressure in the supply-side
of the duct to a 0 to 5 volt DC voltage. The DC voltage
is sent to the Unit Controller and compared against the
“DUCT STATIC PRESS ACTIVE SP”. The transducer is
factory wired, but pneumatic tubing must be fi eld supplied
and installed (refer to Section 2 “INSTALLATION” in this
manual).
The Duct Static Pressure Transducer measures
differential pressure between the pressure in the duct
and atmospheric pressure. When verifying transducer
operation, the technician must insert a tee in 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 duct pressure
vs. output volts DC from the transducer. Table 8-2 shows
the relationship between the pressure applied to the duct
pressure transducer and the output voltage. The output is
linear between 0" WC and the SPAN. The “DUCT PRESS
TRANSDUCER SPAN”
can be set to 1.25, 2.5 or 5" WC.
The “DUCT PRESS TRANSDUCER SPAN” must always
be set based on the span of the transducer installed.

°F

VOLTAGE

RESISTANCE

°C

-25

0.49

139,639

-30.6

-20

0.53

127,453

-28.9

-15

0.60

109,624

-26.1

-10

0.69

94,519

-23.34

-5

0.78

81,665

-20.55

0.0

0.88

70,750

-17.78

5

0.98

61,418

-15.00

10

1.10

53,426

-12.22

15

1.22

46,582

-9.44

20

1.35

40,703

-6.67

25

1.48

35,639

-3.89

30

1.62

31,269

-1.11

35

1.77

27,490

1.67

40

1.91

24,219

4.44

45

2.06

21,377

7.22

50

2.21

18,900

10.00

TABLE 8-1 – TEMPERATURE SENSOR RESISTANCE

°F

VOLTAGE

RESISTANCE

°C

55

2.36

16,744

12.78

60

2.51

14,681

15.56

65

2.66

13,216

18.33

70

2.80

11,771

21.11

75

2.94

10,502

23.89

80

3.08

9,388

26.67

85

3.21

8,404

29.45

90

3.33

7,537

32.22

95

3.45

6,770

35.0

100

3.56

6,090

37.78

105

3.66

5,487

40.56

110

3.76

4,951

43.34

115

3.85

4,475

46.11

120

3.94

4,050

48.89

125

4.02

3,671

51.66

130

4.09

3,332

54.44

135

4.16

3,029

57.22

SECTION 8 – SERVICE

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