Honeywell PC8900A Manual page 39

NOTE: When a discharge air temperature sensor is installed
and configured in an application, we recommend
interrupting the power supply briefly before leaving
the site. This removes the discharge air temperature
from the display when the CHECK key is pressed
and avoids confusion.
C7189A Remote Indoor Temperature Sensor
The C7189A Wall Mount Temperature Sensor provides the
input required by the Comfort Center™ control system to
sense the indoor air space temperature. See Fig. 40 for the
resistance vs. temperature characteristics for the C7189A
Remote Indoor Temperature Sensor.
At a remote location, the C7189A can also average
temperature in several ways:
• PC8900A and one C7189A.
• Four or nine C7189As in series/parallel networks.
• PC8900A and a C7189A network (four or nine sensors).
NOTE: The remote temperature (or temperature averaging
network temperature) is displayed on the PC8900A
with the Time, Day, and Mode of operation. Pressing
the CHECK key does not display the remote
temperature separately.
2300
2200
2100
2000
1900
1
1800
1700
1600
1500
1400
1300
1200
1000
40
(4)
Fig. 40. C7189A Remote Temperature Sensor resistance vs. temperature performance characteristics.
70 80
50 60
(10) (16) (21) (27)
TEMPERATURE
1 RESISTANCE DECREASES 18.6 OHMS PER 1 F
CHANGE OR 33.4 OHMS PER 1 C CHANGE.
Keypad Lockout
The keypad lockout feature allows temporary settings to be
made, but the installer setup and program settings can not be
changed. This feature gives the PC8900A the security of a
locking cover with flexibility to meet the user's schedule. To
activate keypad lockout, press and hold RUN until LOCK KEY
shows on the display (approximately three seconds). To
deactivate keypad lockout, press and hold RUN until OPEN
KEY shows on the display.
CHECK Key
Press the PC8900A CHECK key to display the following
information:
• Outdoor temperature (if C7089A installed).
• Humidity level in room.
• Discharge air temperature (if C7100A installed).
• Heating and cooling setpoints.
• Fan setting.
• Ventilation setting.
• System setting.
If the Check LED is lighted, troubleshooting messages are
displayed. Refer to Fig. 41 for flowchart of troubleshooting
messages.
ROOM TEMPERATURE
F
46
48
50
52
54
56
58
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
90 100
F 94
(32) (38)
( C )
96
98
100
39
OHMS OF
RESISTANCE
C
7.8 2131 to 2094
8.9 2094 to 2057
10.0 2057 to 2019
11.1 2019 to 1982
12.2 1982 to 1945
13.3 1945 to 1908
14.4 1908 to 1871
15.6 1871 to 1833
16.7 1833 to 1796
17.8 1796 to 1759
18.9 1759 to 1722
20.0 1722 to 1685
21.1 1685 to 1647
22.2 1647 to 1610
23.3 1610 to 1573
24.4 1573 to 1536
25.6 1536 to 1499
26.7 1499 to 1461
27.8 1461 to 1424
28.9 1424 to 1387
30.0 1387 to 1350
31.1 1350 to 1313
32.2 1313 to 1275
33.3 1275 to 1238
34.4 1238 to 1201
35.6 1201 to 1164
36.7 1164 to 1127
37.8 1127 to 1089
M6357
68-0173—3