Honeywell PC8900A Manual page 38

Center™ program turns on the heat. When the heat raises the
temperature so there is a call for cooling and the
dehumidification requirement is still not met, cooling starts
again. This switching continues until the dehumidification and
cooling setpoints are met. This feature assures that the
occupants do not experience excessive temperature drop due
to the need for dehumidification.
CO Monitor
2
When a CO monitor is configured and installed, the Comfort
2
Center™ programl turns on ventilation (if configured for
ventilation), or
system fan (if configured for no ventilation), in
response to a high CO monitor reading.
2
3900
3800
3700
3600
1
3500
3400
3300
3200
3100
3000
2900
2800
-40 -20
(-40) (-29)
1 RESISTANCE INCREASES 4.84 OHMS PER 1 F CHANGE OR 8.7 OHMS PER 1 C CHANGE.
M6358
Fig. 39. C7089A Outdoor Temperature Sensor and C7100A Discharge Temperature Sensor
C7100A Discharge Air Temperature Sensor
The C7100A Discharge Air Temperature Sensor mounts on
the duct wall or plenum surface with integral mounting flange
or in a 2 x 4 in. junction box. The C7100A senses the air temper-
ature in the discharge and if the temperature is not acceptable for
the heating or cooling setting, the Comfort Center™ control
system lights the check LED and presents a Check message.
See Fig. 39 for the resistance vs. temperature characteristics for
the C7100A Discharge Air Temperature Sensor.
68-0173—3
20 40 60 80
0
(-18) (-7) (5) (16) (27)
TEMPERATURE
resistance vs. temperature performance characteristics.
C7089A Outdoor Temperature Sensor
The outdoor temperature sensor is necessary for the Frost
control feature to be activated. The Comfort Center™ control
system takes the outdoor temperature reading and calculates
the dewpoint to help prevent humidity from accumulating on
the windows. With the C7089A installed and configured, the
user can read the outdoor temperature by pressing the
CHECK key. See Fig. 39 for the resistance vs. temperature
characteristics for the C7089A Outdoor Temperature Sensor.
When a C7089A Outdoor Temperature Sensor is configured
and installed and the PC8900A is configured for humidity
control in the heating mode, the frost control feature is
enabled.
140 160
100 120 F
(38) (49) (60) (79) ( C )
The discharge air temperature is displayed on the PC8900A
when the Check key is pressed. If the PC8900A is configured
for a discharge air temperature but the discharge air tempera-
ture is not displayed, then a power outage has cleared the
discharge air temperature reading from the Check feature. To
re-establish the discharge air temperature, enter the installer
setup mode for a few seconds. After the RUN key is pressed,
the discharge air temperature is displayed when the CHECK
key is pressed (until another power outage occurs).
38
OUTDOOR TEMPERATURE
OHMS OF
RESISTANCE
F C
-40 -40.0 2929 to 2905
-35 -37.2 2953 to 2929
-30 -34.4 2978 to 2953
-25 -31.7 3002 to 2978
-20 -28.9 3026 to 3002
-15 -26.1 3050 to 3026
-10 -23.3 3074 to 3050
-5 -20.6 3099 to 3074
0 -17.8 3123 to 3099
5 -15.0 3147 to 3123
10 -12.2 3171 to 3147
15 -9.4 3195 to 3171
20 -6.7 3220 to 3195
25 -3.9 3244 to 3220
30 -1.1 3268 to 3244
35 1.7 3292 to 3268
40 4.4 3316 to 3292
45 7.2 3341 to 3316
50 10.0 3365 to 3341
55 12.8 3389 to 3365
60 15.6 3413 to 3389
65 18.3 3437 to 3413
70 21.1 3462 to 3437
75 23.9 3486 to 3462
80 26.7 3510 to 3486
85 29.4 3534 to 3510
3558 to 3534
90 32.2
95 35.0 3583 to 3558
100 37.8 3607 to 3582
105 40.6 3631 to 3607
110 43.3 3655 to 3631
115 46.1 3679 to 3655
120 48.9 3703 to 3679
125 51.7 3728 to 3703
130 54.4 3752 to 3728
135 57.2 3776 to 3752
140 60.0 3800 to 3776
145 62.8 3824 to 3800
150 65.6 3849 to 3824