York YCUL0045E, Installation Operation & Maintenance

Page: 100 / 144

JOHNSON CONTROLS
100
FORM 150.63-NM8 (1020)
SERVICE AND TROUBLESHOOTING
CHECKING INPUTS AND OUTPUTS
DIGITAL INPUTS
Refer to the unit wiring diagram. All digital inputs are
connected to J13 of the I/O Board. The term “digital”
refers to two states – either on or off. As an example,
when the air proving switch is closed, 30 volts DC will
be applied to J13, pin 5 (J13-5) of the I/O Board. If
the air proving switch is open, 0 volts DC will then be
present at J13-5.
Pin 1 of J13 is an unregulated 30VDC that is the DC
voltage source used to supply the DC voltage to the
various contacts, unit switch, flow switch, etc. This
DC source is factory wired to CTB1, terminal 13. Any
switch or contact used as a digital input would be con-
nected to this terminal, with the other end connecting to
its respective digital input on the I/O Board. Any time a
switch or contact is closed, 30VDC would be applied to
that particular digital input. Any time a switch or con-
tact is open, 0VDC would be applied to that particular
digital input.
Typically, as high as 34VDC could be measured for the
DC voltage on the digital inputs. This voltage is in refer-
ence to ground. The unit case should be sufficient as a
reference point when measuring digital input voltages.
ANALOG INPUTS – Temperature
Refer to the unit wiring diagram . Temperature inputs are
connected to the I/O Board on plug J6. These analog
inputs represent varying DC signals corresponding to
varying temperatures. All voltages are in reference to
the unit case (ground). Following are the connections
for the temperature sensing inputs:
Outside Air Sensor
J6-6 = +5VDC regulated supply to sensor.
J6-9 = VDC input signal to the I/O Board. See Table
29 for voltage readings that correspond to
specific outdoor temperatures.
J6-3 = drain (shield connection = 0 VDC )
TABLE 29
–
OUTDOOR AIR SENSOR
TEMPERATURE/VOLTAGE/
RESISTANCE CORRELATION
TEMP °F VOLTAGE RESISTANCE TEMP C°
0 0.7 85398 -18
5 0.8 72950 -15
10 0.9 62495 -12
15 1.0 53685 -9
20 1.1 46240 -7
25 1.2 39929 -4
30 1.4 34565 -1
35 1.5 29998 2
40 1.7 26099 4
45 1.8 22673 7
50 2.0 19900 10
55 2.2 17453 13
60 2.3 15309 16
65 2.5 13472 18
70 2.6 11881 21
75 2.8 10501 24
80 2.9 9298 27
85 3.1 8250 29
90 3.2 7332 32
95 3.4 6530 35
100 3.5 5827 38
105 3.6 5209 41
110 3.7 4665 43
115 3.8 4184 46
120 3.9 3759 49
125 4.0 3382 52
130 4.1 3048 54