Home

href="
Perfect Climate Comfort Center™  
Control System  
PRODUCT DATA  
FEATURES  
The PC8900A mounts in the living space and accurately  
measures and controls room temperature and humidity.  
Only four wires required for installation.  
Large, continuously lit LCD.  
Seven-day (auto copy) programming.  
Simultaneous display of heat and cool setpoints.  
Keyboard lockout protection available.  
No batteries required, indefinite program retention.  
Circulation fan setting improves indoor air quality.  
Field configurable for:  
PC8900A  
Automatic or manual changeover.  
°F or °C display.  
12- or 24-hour clock.  
Adaptive Intelligent Recovery™ control or conven-  
tional recovery.  
Humidity control in heating or cooling.  
Outdoor, remote, and discharge temperature sen-  
sors available.  
Fan overrun in cooling.  
Ventilation control.  
The W8900A-C mounts near the equipment. The  
PC8900A, heating, cooling, ventilation and  
dehumidification equipment and all additional sensors  
are wired to the W8900A-C.  
W8900A-C  
Compatible with most 24 Vac Systems.  
Remote sensor, discharge sensor, outdoor sensor and  
GENERAL  
CO monitor available.  
2
This document contains information on the Perfect Climate  
Comfort Center™ Control System including components and  
accessories. Some components and accessories include the  
PC8900A Control Panel, W8900A-C Remote Module,  
C7189A Remote Indoor Sensor, C7089A Outdoor Sensor,  
C7100A Discharge Air Sensor, CO2 Monitor, CM8900A  
Communication Module, and W8735B Telephone Access  
Module.  
Optional remote communications available.  
Contents  
General .............................................................................  
Features ...........................................................................  
Specifications ....................................................................  
Ordering Information ........................................................  
Installation ........................................................................  
Wiring Diagrams ...............................................................  
W8900A,C Hookup Diagrams .......................................  
W8900B Hookup Diagrams ........................................... 14  
W8900A,B,C Humidity Control Hookup Diagrams ........ 18  
Installer Setup ................................................................... 24  
Programming PC8900A .................................................... 27  
Checkout .......................................................................... 33  
Operation .......................................................................... 34  
Troubleshooting ................................................................ 40  
Glossary ........................................................................... 44  
1
1
2
2
5
9
9
The Comfort Center control system provides 24 Vac energy  
saving control for a heating and cooling system, while  
providing reliable and precise temperature, ventilation and  
humidity control.  
®
U.S. Registered Trademark  
Copyright © 2001 Honeywell • All Rights Reserved  
68- 0173- 3  
href="
SPECIFICATIONS  
IMPORTANT  
C7100A: See Fig. 4.  
C7189A: See Fig. 5.  
PC8900A: See Fig. 6.  
W8900A-C: See Fig. 7.  
The specifications given in this publication do not  
include normal manufacturing tolerances; therefore,  
an individual unit might not exactly match the listed  
specifications. Also, this product is tested and cali-  
brated under closely controlled conditions, and some  
minor differences in performance can be expected if  
those conditions are changed.  
Operating Ambient Temperature Range:  
NOTES: System is capable of turning on heat at 0°F (-18°C).  
C7089A: -40° to 128°F (-40° to 53°C).  
C7100A: 40° to 150°F (4° to 66°C).  
Models:  
C7189A: 40° to 95°F (4° to 35°C).  
PC8900A: 40° to 110°F (4° to 43°C).  
W8900A-C: -40° to 150°F (-40° to 66°C).  
The PC8900A Comfort Center™ Control Panel mounts in the  
living space and accurately measures and controls room  
temperature and humidity. The W8900A-C Remote Module  
provides a wiring panel and switching for the Perfect Climate  
Comfort Center™ Control System. See Table 1.  
Shipping Temperature Range (All Components): -20° to  
150°F (-29° to 66°C).  
System Components and Accessories (See Fig. 1):  
C7089A1002 Outdoor Sensor: Used to measure outdoor tem-  
perature.  
Operating Relative Humidity Range (All Components):  
5 percent RH to 90 percent RH, noncondensing.  
C7100A1015 Discharge Air Sensor: Used to sense tempera-  
ture in discharge or return air.  
C7189A1001 Remote Indoor Sensor: Used for remote sensor  
applications.  
Mounting Means:  
C7089A Outdoor Sensor: Mounts outside of living space using  
locally obtained mounting hardware.  
C7100A Discharge Air Sensor: Mounts in discharge air duct,  
near air exchanger in a 2 x 4 in. outlet box or on a flat duct  
or plenum surface. The temperature sensor probe passes  
through a 7/8 in. knockout in the 2 x 4 in. outlet box.  
C7189A Remote Indoor Sensor: Mounts directly on the wall  
using mounting screws and anchors provided.  
PC8900A Control Panel:  
CM8900A1009 Communication Module: Used for remote  
communication.  
W8735B1003 Telephone Access Module: Used for remote  
communication.  
2
02689A Mounting Plate Accessory: Used when C7189A  
Remote Indoor Sensor cannot cover wall marks from old  
thermostat.  
Without Remote Sensor: Mounts directly on the wall in liv-  
ing space using mounting screws and anchors provided.  
With Remote Sensor: Mounts directly on the wall in a  
closet or other convenient location using mounting  
screws and anchors provided.  
2
05224A Wall Cover Plate: Used when PC8900A Control  
Panel cannot cover wall marks from old thermostat.  
2007496-001 Replacement Door: Used for PC8900A Control  
Panel.  
3
Dimensions:  
W8900A-C Remote Module: Mounts directly on the wall, near  
HVAC equipment or cold air return, using mounting screws  
and anchors provided.  
205224A: See Fig. 2.  
C7089A: See Fig. 3.  
Table 1. W8900A-C Models.  
Use with  
Heat  
Stages  
Cool  
Stages  
Vent  
Humidity  
Humidity  
Model  
W8900A  
W8900B  
W8900C  
System Type  
Conventional  
Heat pump  
Adjustment Adjustment Heat Adjustment Cool  
Use with  
PC8900A  
2a  
2
3
2
yes  
yes  
yes  
yes  
yes  
yes  
yes  
yes  
yesb  
2
2
PC8900A  
PC8900A  
Conventional  
a
b
Models with O and B terminals have single stage cooling.  
Uses reheat. See Operation section.  
ORDERING INFORMATION  
When purchasing replacement and modernization products from your TRADELINE® wholesaler or distributor, refer to the  
TRADELINE® Catalog or price sheets for complete ordering number.  
If you have additional questions, need further information, or would like to comment on our products or services, please write or  
phone:  
1
2
.
.
Your local Home and Building Control Sales Office (check white pages of your phone directory).  
Home and Building Control Customer Relations  
Honeywell, 1885 Douglas Drive North  
Minneapolis, Minnesota 55422-4386 (800) 328-5111  
In Canada—Honeywell Limited/Honeywell Limitée, 35 Dynamic Drive, Scarborough, Ontario M1V 4Z9.  
International Sales and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France,  
Germany, Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A.  
68-0173—3  
2
href="
Finish:  
Heat Pump Failure Input (L Terminal on W8900B Models):  
24 Vac load, 50/60 Hz, 0.3 VA load.  
C7189A Wall Mount Remote Indoor Sensor: Premier White®  
color.  
CO Monitor Input (CO Terminal on all W8900A-C Mod-  
2
2
PC8900A Control Panel: Premier White® color.  
els): 24 Vac load, 50/60 Hz, 0.3 VA load.  
W8900A-C Remote Module: Charcoal gray color.  
Output Ratings:  
Humidity Control Output Relay: 50 VA at 24 Vac.  
Ventilation, W1, W2, Y1, Y2, E, G, O, B, AUX, Y1/W1:  
a. 1.5A running, 3.5A inrush at 200,000 cycles  
(30 Vac).  
Clock Accuracy: ± 1 minute per month.  
Approvals:  
FCC Class B: Pending.  
NEMA DC-3: Not required.  
b. 1.5A running, 7.5A inrush at 100,000 cycles  
(
30 Vac).  
Batteries: No batteries required. During power outages, time  
is retained for six hours. All programmed setpoints and  
times are retained indefinitely.  
Run: 40% power factor minimum.  
Inrush: 50% power factor minimum.  
Temperature Setting Range: PC8900A: 45° to 88°F  
Resistance Characteristics of Sensors:  
(7° to 31°C).  
C7089A Outdoor Sensor: PTC Sensor. See Fig. 39 in the  
Operation section for sensor resistance characteristics.  
C7100A Discharge Air Sensor: See Fig. 39 in the Operation  
section for sensor resistance characteristics.  
C7189A Remote Indoor Sensor: NTC Sensor. See Fig. 40 in  
the Operation section for sensor resistance characteristics.  
Humidity Setting Range:  
PC8900A: 10 to 80% RH.  
Cooling: 40 to 80% RH.  
Heating: 10 to 80% RH.  
Calibration: C7089A, C7100A, C7189A, and PC8900A are  
Auxiliary Heat and Emergency Heat Indication: PC8900A  
display indicates when auxiliary heat and emergency heat  
are activated.  
factory calibrated and require no field calibration.  
CO Monitors: The W8900A-C allows for connection of a  
2
CO Monitor with uncommitted contacts.  
2
Input Ratings:  
20 to 30 Vac, 50/60 Hz.  
C7089A  
Outdoor Sensor  
PC8900A  
Comfort Center™  
Control Panel  
W8735B  
Telephone Access  
Module  
W8900A-C  
Remote Module  
C7189A  
CM8900A  
C7100A  
Remote Indoor Sensor  
Communication Module  
Discharge Air Sensor  
Fig. 1. System components and accessories.  
3
68-0173—3  
href="
1
-1/2 (38)  
6
(
152)  
7
/8  
22)  
(
7
/8  
22)  
(
M4488  
3
-1/4 (83)  
8
-1/2 (216)  
Fig. 3. Dimensions for C7089A Outdoor Sensor  
Mounting Clip in in. (mm).  
M7513  
Fig. 2. Dimensions for 205224A Wall Cover  
Plate in in. (mm).  
1
(
-3/16 1-13/16  
30)  
(46)  
1-3/16  
(30)  
3
(
/4  
19)  
13-1/4 (336)  
M4461  
1
-13/16  
46)  
(
Fig. 4. Dimensions for C7100A Discharge Air Sensor in in. (mm).  
4
(
-5/8  
117)  
4-5/8  
(117)  
3
(
-1/4  
83)  
1
(
-1/8  
29)  
2
-3/4 (70)  
2-3/4 (70)  
M4465  
FRONT VIEW  
SIDE VIEW  
FRONT VIEW (COVER OFF)  
Fig. 5. Dimensions for C7189A Remote Indoor Sensor in in. (mm).  
68-0173—3  
4
href="
6
(152)  
1-5/8 (41)  
3
-1/4 (83)  
4
(102)  
3
(
-3/8  
86)  
7
/8  
22)  
(
7
/8  
22)  
(
6
-3/8 (162)  
SYSTEM  
CHECK  
4
102)  
(
SET  
CLOCK  
SYSTEM  
HEAT OFF COOL  
FAN  
AUTO ON CIRC  
HEAT/COOL  
SETPOINTS  
DAY  
SELECT  
PERIOD  
HUMIDITY  
VENTILATE  
HOLD  
RUN  
NOTE:  
PC8900 SHOWN WITH  
COVER REMOVED.  
TIME  
TIME  
CANCEL  
M6356  
Fig. 6. Dimensions for PC8900A Control Panel in in. (mm).  
MERCURY NOTICE  
If this control is replacing a control that contains  
mercury in a sealed tube, do not place your old control  
in the trash.  
7
(
-13/16  
197)  
Contact your local waste management authority for  
instructions regarding recycling and the proper  
disposal of this control or of an old control containing  
mercury in a sealed tube.  
8
(
-3/4  
222)  
If you have questions, call Honeywell Inc. at  
1
5
-800-468-1502, Monday through Friday, 7:00 a.m. to  
:30 p.m., Central time.  
1
/2 (12)  
INSTALLATION  
3
(
/4  
19)  
4
-7/8 (124)  
6
6
-3/8 (163)  
-3/8 (163)  
(
4) 3/8 (5)  
When Installing this Product…  
1.  
Read these instructions carefully. Failure to follow  
instructions can damage the product or cause a  
hazardous condition.  
2
51)  
(
2.  
3.  
4.  
Check the ratings on the product to make sure the  
product is suitable for your application.  
Installer must be a trained, experienced service  
technician.  
After completing installation, use these instructions to  
check out product operation.  
NOTE: W8900 SHOWN WITH COVER REMOVED.  
M6355  
Fig. 7. Dimensions for W8900A-C Remote  
Module in in. (mm).  
5
68-0173—3  
href="
CAUTION  
Disconnect power supply before wiring to prevent  
electrical shock or equipment damage.  
W8900  
WALL  
Mounting the W8900A-C Remote Module  
Locate the W8900A-C in the equipment room near the HVAC  
equipment. See Fig. 8.  
MOUNTING  
HOLES (4)  
CAUTION  
Do not mount the W8900A-C inside any HVAC  
equipment. Mounting the W8900A-C inside HVAC  
equipment can cause damage to the W8900A-C.  
1
.
Grasp the top edge of the W8900A-C cover, either at  
thecenterorbothcorners,andpullitofffrom the base.  
Locate the four mounting holes. See Fig. 9.  
Position the W8900A-C on wall or cold air return. Level  
the W8900A-C for appearance only; the device will  
function properly even when not level. Use a pencil to  
mark the mounting holes on the wall.  
2.  
.
3
MOUNTING  
SCREWS (4)  
M4463  
W8900  
Fig. 9. Mounting W8900A-C Remote Module.  
Wiring the W8900A-C to the HVAC Equipment  
CAUTION  
Disconnect power supply before connecting  
wiring to prevent electrical shock or equipment  
damage.  
FURNACE OR BOILER  
WATER HEATER  
M4459  
Fig. 8. W8900A-C location example.  
Wiring must comply with applicable codes, ordinances, and  
regulations.  
4
.
.
Remove the W8900A-C from the wall, and drill 3/16 in.  
holes in the wall (if drywall) as marked. For firmer mate-  
rial such as plaster or wood, drill 7/32 in. holes. Gently  
tap anchors (provided) into drilled holes until flush with  
the wall.  
Reposition the W8900A-C over the holes. Loosely insert  
the four mounting screws (included) into the holes.  
IN REPLACEMENT INSTALLATION:  
1. Locate the terminal wiring strip on the old thermostat.  
2. Note the wire color for each wiring terminal used.  
3. Remove the wires connected to the old thermostat and  
other controls. Tape off unused wires.  
4. Use Table 2 or 3 to identify the W8900A-C terminal  
labels. Connect the same loads that were connected to  
the old thermostat to the W8900A-C Remote Module  
with a new bundle of 18-gauge color-coded thermostat  
wire; see Fig. 10. See Fig. 11 through 20 for wiring dia-  
grams for specific equipment applications.  
5
68-0173—3  
6
href="
IMPORTANT  
Be sure to connect the C terminal to transformer  
W8900  
common.  
IN NEW INSTALLATION:  
1
2
.
.
Locate the terminal strip(s) on the HVAC equipment.  
Refer to Fig. 11 through 20 for wiring diagrams for spe-  
cific equipment applications.  
FOR STRAIGHT  
CONNECTION—  
STRIP 5/16 IN. (8 MM)  
3
.
.
Connect all loads to the appropriate W8900A-C wiring  
terminal using 18-gauge, color-coded thermostat wire;  
see Fig. 10.  
Use a small screwdriver to connect the loads. Do not  
overtighten; device can be damaged.  
FOR WRAPAROUND  
CONNECTION—  
STRIP 7/16 IN. (11 MM)  
4
M4464  
Fig. 10. Proper wiring technique for  
W8900A-C and PC8900A.  
Table 2. Conventional Applications (W8900A or C).  
Function  
PC8900A Control Panel  
W8900A, C Terminal Designation  
Existing Thermostat Designation  
1
2
B
PC8900A Control Panel  
PC8900A Control Panel  
PC8900A Control Panel  
Heating, changeover valve  
24 Vac Transformer Common  
Carbon Dioxide Monitor  
3
4
B
C
C
CO2  
VNT  
G
VNT Relay  
G
Fan Relay  
GND  
HUM  
OUT  
Ground  
O
Humidity Relay  
Outdoor Air Temperature Sensor  
Cooling, Changeover Valve  
24 Vac System Transformer  
24 Vac Cooling Transformer  
24 Vac Heating Transformer  
Remote Air Temperature Sensor  
Fan Control—Evaporative Cooling  
Heat Pump Contactor  
O
R
R
RC  
RC  
RH  
F
RH  
S, S1  
See note a  
See note b  
T, T1  
W1  
P
Discharge Air Temperature Sensor  
Heating Relay  
W
W1  
W2  
Y
W1  
Stage 1 Heat Relay  
W2  
Stage 2 Heat Relay  
Y1  
Cooling Relay  
Y1  
Stage 1 Cool Relay  
Y1  
Y2  
1
Y2  
Stage 2 Cool Relay  
See note c  
See note c  
See note d  
none  
Fan Control (Honeywell dual fuel thermostat [T834])  
Fan Control (Honeywell dual fuel thermostat [T834])  
Filter Light  
2
X
Remote Timer Contacts  
Z
a
b
c
d
PC8900A/W8900A,C are not compatible with evaporative cooling equipment.  
In single stage heat pump applications, jumper W1 and Y1 and connect to Y. Configure the system for Auto Fan in Heat.  
Dual fuel fan feature configured in installer setup.  
Filter light feature available in PC8900A fan accumulation timer feature.  
7
68-0173—3  
href="
Table 3. Heat Pump Applications (W8900B).  
Existing Thermostat  
Existing Thermostat  
Designations  
(Customer Specials)  
W8900B Terminal  
Designations  
Designations  
(Standard)  
Function  
PC8900A Control Panel  
1
2
W3  
B
PC8900A Control Panel  
PC8900A Control Panel  
PC8900A Control Panel  
Stage-3 heat control (strip heat)  
Heating, changeover valve  
24 Vac transformer common  
Carbon dioxide monitor  
3
4
AUXa  
B
C
C
X,B  
CO2  
E
VNT  
G
Emergency heat relay  
VNT relay  
E
G
K
Fan relay  
F
GND  
L
Ground  
L
System monitor  
L
O
Cooling, changeover valve  
24 Vac system transformer  
Remote Air Temperature Sensor  
Discharge Air Temperature Sensor  
Stage-2 heat control (compressor)  
Compressor contactor  
Compressor contactor  
Stage-1 cool control  
O
R
R
R
V
S, S1  
T, T1  
W2b  
Y1/W1c  
Y1/W1c  
Y1/W1c  
Y1/W1c