® U.S. Registered Trademark
Copyright © 2002 Honeywell • • All Rights Reserved
INSTALLATION INSTRUCTIONS
69- 1344- 1
W8703A
Damper Interface Module
APPLICATION
The W8703A Damper Interface Module (DIM) controls
up to three conventional zone dampers when used with
T8635L Microelectronic Communicating Programmable
Thermostats and the W8635 Equipment Interface
Module, Table 1. The W8703A uses Enviracom, a low-
cost wired communications protocol.
Using the W8703A Damper Interface Module with up to
three T8635L Microelectronic Communicating Program-
mable Thermostats and a W8635A,B Equipment
Interface Module enables the following features:
• Time synchronization.
• Shared filter indication.
• Outdoor temperature display in all zones with only
one C7089B Outdoor Temperature Sensor
connected.
• Vacation Hold in all zones.
• Check LED in all zones (when used with the
W8635B Equipment Interface Module for heat
pumps).
• System switch setting automatically changes in all
zones.
• Individual fan control in each zone.
NOTES:
— Up to three T8635 Thermostats can be con-
trolled with the W8703A Damper Interface
Module.
— Up to six zones can be controlled using two
W8703A and up to nine zones can be con-
trolled using three W8703A.
Table 1. W8703A Description.
Required Accessories
1. T8635L Microelectronic Communicating Pro-
grammable Thermostat.
2. W8635A Equipment Interface Module for up to
2H/2C conventional applications or W8635B
Equipment Interface Module for up to 2H/1C heat
pump applications.
INSTALLATION
When Installing this Product . . .
1. Read these instructions carefully. Failure to follow
them could damage the product or cause a haz-
ardous condition.
2. Check the ratings given in the instructions and on
the product to make sure the product is suitable
for your application.
3. Installer must be a trained, experienced service
technician.
4. After installation is complete, check out product
operation as provided in these instructions.
5. Follow local codes for installation and application.
CAUTION
Voltage Hazard.
Can cause electrical shock or equipment
damage.
Disconnect power before beginning installation.
Location
Locate the W8703A in the equipment room near the
HVAC equipment. See Fig 1.
Model Application Recommended Zone Dampers Comments
W8703A Controls up to
three zone
dampers.
Trol-A-Temp Model AOBD
or
Trol-A-Temp Model ARD
or
Trol-A-Temp Model ZD
Use with T8635L Microelectronic
Communicating Programmable
Thermostat and W8635A,B Equipment
Interface Modules.
W8703A DAMPER INTERFACE MODULE
69-1344-1 2
Fig. 1. Mounting W8703A on wall or duct.
Mounting
CAUTION
Mounting Location Hazard.
Mounting W8703A inside HVAC equipment
can damage the DIM.
Mount the W8703A only on the outside of HVAC
equipment.
1. Remove the cover from the W8703A by pulling it
from the center or the corners of the module.
2. Locate the two mounting holes. See Fig 1.
3. Position the W8703A on the wall or the cold air
return.
4. Level the W8703A for appearance only; the
device will function properly even when not level.
5. Use a pencil to mark the position of the mounting
holes on the wall or cold air return.
6. Remove the W8703A from the wall or cold air
return and drill 3/16 in. holes in the wall (if drywall)
where marked. For firmer materials such as plas-
ter or wood, drill 7/32 in. holes. See Fig. 2.
7. Gently tap the anchors (provided) into the holes
until flush with the wall.
8. When mounting on the cold air return, drill a pilot
hole where marked.
9. Reposition the W8703A over the holes.
10. Loosely insert the screws into the holes.
11. Tighten the screws.
Fig. 2. Mounting W8703A Damper Interface Module.
WIRING
CAUTION
Voltage Hazard.
Can cause electrical shock or equipment
damage.
Disconnect power before beginning installation.
All wiring must comply with local codes and ordinances.
Use the following steps:
1. Loosen the terminal screws on the W8703A and
connect the system wires; see Fig. 3 and Table 2.
2. Securely tighten each terminal screw.
Fig. 3. Correct wiring technique.
M13427
WATER HEATER
W8703A
FURNACE OR BOILER
ZONE C
COM
TR1
TR2
2
3
CLOSE
OPEN
CLOSE
OPEN
CLOSE
OPEN
MOUNTING
HOLES (2) MOUNTING
SCREWS (2)
W8703
WALL
M13440
1
ZONE B ZONE A
M4826
FOR WRAPAROUND
INSERTION STRIP
7/16 IN. (11 MM).
FOR STRAIGHT INSERTION
STRIP 5/16 IN. (8 MM).
W8703A DAMPER INTERFACE MODULE
3 69-1344-1
Table 2. Terminal Designations
3. See Fig. 4 to wire the T8635L, W8635A and
W8703A in forced air systems.
4. See Fig. 5 and 6 to wire hydronic heat with V8043
zone valves.
5. See Fig. 7-9 to wire hydronic heat with circulators.
6. See Fig. 10 to wire hydronic heat with V8043
zone valves and an indirect water heater.
7. See Fig. 11 to wire hydronic heat with time-out on
an indirect water heater.
8. Connect a 24 VAC transformer to the W8703.
Connect HVAC system 24 VAC to the W8635.
Provide disconnect means and overload protec-
tion as required.
9. If the application is for 4-6 forced air zones, then
connect an additional W8703 and a correspond-
ing transformer. For 6-9 zones, then connect a
third W8703 and a corresponding transformer.
See SETTINGS for instructions on how to set the
DIP switches on the W8703
10. If the application is for 4-6 hydronic zones, con-
nect an additional W8703 and a corresponding
transformer. Wire the second W8703 COM termi-
nal to terminal 4 on the R8222N1011, and termi-
nal number 6 on the relay to zone 4-6 zone valves
or circulator relays. For 7-9 hydronic zones use
the normally open contacts on a 4PDT 4 pole
relay in the same way for each of the three
W8703 panels.
Fig. 4. T8635L/ W8703A/ W8635A wiring diagram.
W8703A Terminal Designations Function
1 To communications bus.
2 To communications bus.
3 To communications bus.
TR1 To external 24 Vac transformer – to power zone dampers.a
aTransformer must be appropriately sized to supply power to total damper load (60 VA maximum).
TR2 To external 24 Vac transformer – to power zone dampers.a
Zone A Open Connect to zone 1 zone damper.b
b30 VA maximum damper load per zone.
Closed
Zone B Open Connect to zone 2 zone damper.b
Closed
Zone C Open Connect to zone 3 zone damper.b
Closed
L1
(HOT)
L2
1
SYSTEM
TRANSFORMER
COOL 1
RELAY
HEAT 2
RELAY
FAN
RELAY
OT
OT 2
13
FACTORY INSTALLER JUMPERS.
M13430A
C7089B
OUTDOOR
TEMPERATURE
SENSOR
1
T8635L
HEAT 1
RELAY
W8635A
C
R
RH
RC
1
2
3
Y2
W2
Y1
G
W1
COOL 2
RELAY
W8703A
L1
(HOT)
L2
EXTERNAL
40 VA
TRANSFORMER
OT
OT 2
13
T8635L
OT
OT 2
13
T8635L
ZONE AZONE B
ZONE C
CLOSE
OPEN
OPEN
CLOSE
OPEN
CLOSE
COM
TR1
TR2
2
3
1
546Z
213X
546Z
213X
546Z
213X
MODEL AOBD
ZONE DAMPER
MODEL ARD
OR ZD DAMPER
W8703A DAMPER INTERFACE MODULE
69-1344-1 4
Fig. 5. Hydronic heat with V8043 zone valves and non-zoned air conditioning wiring diagram.
V8043F
END
SWITCH
TH-TR
TH
TR
L1
(HOT)
L2
SYSTEM
TRANSFORMER
W8635A
C
R
RH
RC
1
2
3
Y2
W2
Y1
G
W1
W8703A
L1
(HOT)
L2
EXTERNAL
40 VA
TRANSFORMER
ZONE AZONE B
ZONE C
CLOSE
OPEN
OPEN
CLOSE
OPEN
CLOSE
COM
TR1
TR2
2
3
1
V8043F
END
SWITCH
TH-TR
TH
TR
BOILER
13
V8043F
END
SWITCH
TH-TR
TH
TR
OT
OT 2
13
C7089B
OUTDOOR
TEMPERATURE
SENSOR
T8635L
OT
OT 2
13
T8635L
OT
OT 2
13
T8635L
M20251A
R8222N1011
T
T
W8703A DAMPER INTERFACE MODULE
5 69-1344-1
Fig. 6. Hydronic heat with V8043 zone valves and air conditioning with dampers wiring diagram.
V8043F
END
SWITCH
TH-TR
TH
TR
W8635A
C
R
RH
RC
1
2
3
Y2
W2
Y1
G
W1
W8703A
L1
(HOT)
L2
EXTERNAL
40 VA
TRANSFORMER
ZONE AZONE B
ZONE C
CLOSE
OPEN
OPEN
CLOSE
OPEN
CLOSE
COM
TR1
TR2
2
3
1
V8043F
END
SWITCH
TH-TR
TH
TR
BOILER
13
V8043F
END
SWITCH
TH-TR
ARD
TH
TR
OT
OT 2
13
C7089B
OUTDOOR
TEMPERATURE
SENSOR
T8635L
OT
OT 2
13
T8635L
OT
OT 2
13
T8635L
M20170A
R8222N1011
FORCED
AIR
HEATING
AND
COOLING
T
T
ARD
ARD
R
C
R
C
C
C
W8703A DAMPER INTERFACE MODULE
69-1344-1 6
Fig. 7. Hydronic heat with circulator relays and no air conditioning wiring diagram.
W8635A
C
R
RH
RC
1
2
3
Y2
W2
Y1
G
W1
W8703A
L1
(HOT)
L2
EXTERNAL
40 VA
TRANSFORMER
ZONE AZONE B
ZONE C
CLOSE
OPEN
OPEN
CLOSE
OPEN
CLOSE
COM
TR1
TR2
2
3
1
13
OT
OT 2
13
C7089B
OUTDOOR
TEMPERATURE
SENSOR
T8635L
OT
OT 2
13
T8635L
OT
OT 2
13
T8635L
R8222N1011
M20168A
Zone B
Open
Zone A
Open
Zone C
Open
R8222N1011 RELAYS FOR EACH CIRCULATOR
BOILER
T
T
C1 C2 C3
120
LINE
VOLTAGE
USE ENCLOSURE AND WIRE FOLLOWING LOCAL CODES AND ORDINANCES.1
1
L1
(HOT)
L2
SYSTEM
TRANSFORMER
W8703A DAMPER INTERFACE MODULE
7 69-1344-1
Fig. 8. Hydronic heat with circulators and non-zoned air conditioning wiring diagram.
W8635A
C
R
RH
RC
1
2
3
Y2
W2
Y1
G
W1
W8703A
L1
(HOT)
L2
EXTERNAL
40 VA
TRANSFORMER
ZONE AZONE B
ZONE C
CLOSE
OPEN
OPEN
CLOSE
OPEN
CLOSE
COM
TR1
TR2
2
3
1
13
OT
OT 2
13
C7089B
OUTDOOR
TEMPERATURE
SENSOR
T8635L
OT
OT 2
13
T8635L
OT
OT 2
13
T8635L
R8222N1011
M20249A
Zone B
Open
Zone A
Open
Zone C
Open
R8222N1011 RELAYS FOR EACH CIRCULATOR
BOILER
T
T
C1 C2 C3
120
LINE
VOLTAGE
FORCED
AIR
HEATING
AND
COOLING
R
C
R
C
C
C
USE ENCLOSURE AND WIRE FOLLOWING LOCAL CODES AND ORDINANCES.1
1
W8703A DAMPER INTERFACE MODULE
69-1344-1 8
Fig. 9. Hydronic heat with circulators and air conditioning zoned with dampers wiring diagram.
W8635A
C
R
RH
RC
1
2
3
Y2
W2
Y1
G
W1
W8703A
L1
(HOT)
L2
EXTERNAL
40 VA
TRANSFORMER
ZONE AZONE B
ZONE C
CLOSE
OPEN
OPEN
CLOSE
OPEN
CLOSE
COM
TR1
TR2
2
3
1
13
OT
OT 2
13
C7089B
OUTDOOR
TEMPERATURE
SENSOR
T8635L
OT
OT 2
13
T8635L
OT
OT 2
13
T8635L
R8222N1011
M20167A
Zone B
Open
Zone A
Open
Zone C
Open
R8222N1011 RELAYS FOR EACH CIRCULATOR
BOILER
T
T
C1 C2 C3
120
LINE
VOLTAGE
ARD
ARD
ARD
USE ENCLOSURE AND WIRE FOLLOWING LOCAL CODES AND ORDINANCES.1
1
FORCED
AIR
HEATING
AND
COOLING
R
C
R
C
C
C
W8703A DAMPER INTERFACE MODULE
9 69-1344-1
Fig. 10. Hydronic heat with V8043 zone valves and indirect water heater wiring diagram.
V8043F
END
SWITCH
TH-TR
TH
TR
W8635A
C
R
RH
RC
1
2
3
Y2
W2
Y1
G
W1
W8703A
L1
(HOT)
L2
EXTERNAL
40 VA
TRANSFORMER
ZONE AZONE B
ZONE C
CLOSE
OPEN
OPEN
CLOSE
OPEN
CLOSE
COM
TR1
TR2
2
3
1
V8043F
END
SWITCH
TH-TR
TH
TR
BOILER
13
V8043F
END
SWITCH
TH-TR
TH
TR
OT
OT 2
13
C7089B
OUTDOOR
TEMPERATURE
SENSOR
T8635L
OT
OT 2
13
T8635L
OT
OT 2
13
T8635L
M20169A
R8222N1011
T
T
RA889A
120 VAC
X2X1N.C.
COM
L2L1
W(T)R(T) C
T T
IWH AQUASTAT
YELLOW
YELLOW IWH
V8044
VALVE
FORCED
AIR
HEATING
AND
COOLING
R
C
R
C
C
C
W8703A DAMPER INTERFACE MODULE
69-1344-1 10
Fig. 11. Hydronic heat with time-out and indirect water heater with no air conditioning wiring diagram.
Wiring W8703 For Hot Water Zoning
Hydronic Zone Applications
Networked zoning can be used to control hydronic
systems with or without ducted air conditioning sys-
tems. The damper interface module controls a 24 Vac
zone valve directly or a 120 Vac circulator using isola-
tion relays.
HYDRONIC ZONING WITH ZONE VALVES
Networked Zoning can control a hydronic system using
Honeywell V8043 or similar zone valves. The zone
valve end switches are wired in parallel and connected
to the Aquastat on the boiler. A relay is used to prevent
the dampers from opening when the heating system is
idle. See Fig. 5.
In a ducted air conditioning system, dampers are con-
nected as shown in Fig. 6. Power closed, spring open,
round ARD or rectangular ZD dampers are recom-
mended. Three-wire, power open/power closed
dampers such as the AOBD are wired as follows:
V8043F
END
SWITCH
TH-TR
TH
TR
L1
(HOT)
L2
SYSTEM
TRANSFORMER
W8635A
C
R
RH
RC
1
2
3
Y2
W2
Y1
G
W1
W8703A
L1
(HOT)
L2
EXTERNAL
40 VA
TRANSFORMER
ZONE AZONE B
ZONE C
CLOSE
OPEN
OPEN
CLOSE
OPEN
CLOSE
COM
TR1
TR2
2
3
1
V8043F
END
SWITCH
TH-TR
TH
TR
BOILER
13
V8043F
END
SWITCH
TH-TR
TH
TR
OT
OT 2
13
C7089B
OUTDOOR
TEMPERATURE
SENSOR
T8635L
OT
OT 2
13
T8635L
OT
OT 2
13
T8635L
M20250A
R8222N1011
YELLOW
YELLOW
T
T T
T
IWH AQUASTAT DELAY ON
BREAK TIMER,
SET FOR 30 MINUTES
IWH
V8044
VALVE
MODEL PMT-40
24 VAC
TRANSFORMER
LINE
VOLTAGE
SENSE
SENSE
NC
COM
W8703A DAMPER INTERFACE MODULE
11 69-1344-1
• The first W8703 Damper Interface Module drives the
zone valves using its open contacts.
• The second W8703 Damper Interface Module,
addressed with the same DIP switch settings as the
first W8703 (Fig. 12-14) drives the AOBD damper.
• AOBD dampers open and close on a call for heat
and on a call for cool. An optional isolation relay can
be used to depower the common wire to the second
W8703 to prevent a call for heat from the operating
damper on a call for heat. Wire the coil to Y1 and C
on the W8635A.
NOTE: The transformer must be appropriately sized to
supply power to the total valve load (60 VA
maximum or 30 VA maximum valve load per
zone).
HYDRONIC ZONING WITH CIRCULATORS
Networked zoning can control a hydronic system zoned
with circulators. The damper module damper terminals
are wired to isolation relays that control the 120 Vac cir-
cuator. See Fig. 8.
If the system uses ducted air conditioning, wire using
Fig. 9.
PRIORITY ZONING
When an indirect water heater (IWH) is used, the
domestic water can be put on a priority zone. This
directs all the available heat from the boiler to the IWH,
if present, when a call for domestic hot water occurs.
Fig. 10 shows an isolation relay used to remove power
from the room-heating zones valves whenever the IWH
Aquastat calls for heat. In addition to powering the isola-
tion relay, the IWH Aquastat also powers the zone valve
for the IWH loop.
Fig. 11 shows a method of adding a time-out feature to
Fig. 10. This feature prevents the Aquastat from steal-
ing the heat for extended periods.
RELAY AND BOILER CONTROL PANELS
Networked zoning can control Honeywell zone valve or
circular panels. Wire similar to Fig. 7 but wire the nor-
mally open contacts on the circulator relays to zone
thermostat R or W contacts on the panel.
On Argo or Taco panels, connect the normally open
contacts to the TT terminals on the panel.
On Tekmar panels, connect the normally open contacts
where the end switches or thermostats are shown in the
Tekmar installation instructions.
SETTINGS
T8635 Thermostat Settings
The T8635 Thermostats must be configured using
Installer Setup. See Installer Setup 51 in Table 6 of the
T8635 Thermostat Installation Instructions.
Set Installer Setup 51 for the correct cycle rate. Use 6
cph for conventional forced air. Use 3 cph for high-effi-
ciency forced air or hydronic applications.
Set Installer Setup 5 to the number of stages of heat.
For example, set to 1 for a single-stage heat system.
Set Installer Setup 8 for the number of stages of cool-
ing. For example, for one stage of cooling, set it to 1.
For a heat only application, set it to 0.
W8703 DIP Switch Settings
Zones a, b, and c on the W8703 correspond with the
thermostat configuration zones 1, 2, and 3, respectively.
DIP switches are set in the factory as shown in Fig. 12.
Fig. 12. Zones 1-3 DIP switch settings.
When two W8703 are connected and the DIP switch is
configured on the second module as shown in Fig. 13,
zones a, b, and c on the W8703 correspond with the
thermostat configuration zones 4, 5, and 6, respectively
.
Fig. 13. Zones 4-6 DIP switch settings.
When three W8703 are connected and the DIP switch is
configured on the third module as shown in Fig. 14,
zones a, b, and c on the W8703 correspond with the
thermostat configuration zones 7,8 and 9, respectively.
Fig. 14. Zones 7-9 DIP switch settings.
M13428
1
0
ZONES 1-3
M20252
1
0
ZONES 4-6
M20253
1
0
ZONES 7-9
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W8703A DAMPER INTERFACE MODULE
Printed in U.S.A. on recycled
paper containing at least 10%
post-consumer paper fibers.
LED Indicators
There are four LED on the W8703A used to indicate
damper position and system communications.
DAMPER POSITION LED
Three two-color LED on the left side of the base are red
when the W8703A is commanding the damper closed,
and green when commanding the damper open.
COMMUNICATION LED
One green LED on the right side of the base flashes
periodically to indicate that system communications are
functional.
CHECKOUT AND TEST
When power is initially applied to the W8703A, the con-
nected dampers are in the Open position.
To test for proper wiring of the W8703A and the associ-
ated zone dampers:
1. Make sure that the zone thermostats are not call-
ing for heating or cooling and that the thermostat
Fan setting is in the Auto position. All heating and
cooling equipment, including the system fan,
should be off. All zone dampers should be in the
Open position (status LED green).
2. Initiate a call for heating or cooling on the Zone 1
thermostat. The system should start, the Zone 1
damper should remain open and all other damp-
ers should close.
3. Initiate the same call in each of the remaining
zone thermostats. The damper in each zone
should open in response to this action.
4. Remove the call for heating or cooling in each
thermostat. The damper in each zone should
close in response to this action.
5. After all calls for heating and cooling are
removed, the system blower should stop and all
dampers should return to the Open position.
TROUBLESHOOTING GUIDE
Symptom Possible Cause Action
No LED are on. Panel is not powered. Check for 24 Vac between TR1 and TR2 terminals; if missing 24 Vac:
— Check if the circuit breaker is tripped; if so, reset the circuit
breaker.
— Check if the Power switch on the HVAC equipment is in the Off
position; if so, set to the On position.
— Check wiring between the thermostat and HVAC equipment—
replace any broken wires and tighten any loose connections.
— If 24 Vac is present, proceed with troubleshooting.
Damper does not
open/close when
expected.
System
communications are
incorrectly connected.
Verify that system communications LED is periodically blinking; if not:
— Check wiring of system. Verify that system terminals 1, 2 and 3
are correctly connected.
Damper is incorrectly
connected to Damper
Interface Module.
Verify correct color of LED is visible: red for Closed and green for
Open; if correct:
— Check wiring of damper. Verify that Open, Close and Com
terminals are correctly connected to damper terminals.
