Aprilaire 6504 Setup guide

Safety & Installation Instructions
Model 6504
Intelligent Zoned Comfort Control System

2© Research Products Corp.
TABLE OF CONTENTS
WARNINGS AND CAUTIONS . . . . . . . . . . . . . . . . . . . . . . .3
CONTROL PANEL SPECIFICATIONS . . . . . . . . . . . . . . . . .3
CONTROL PANEL LAYOUT . . . . . . . . . . . . . . . . . . . . . . . . .4
RUN WIRE FOR THE SYSTEM . . . . . . . . . . . . . . . . . . . . . .5
MOUNT THE CONTROL PANEL . . . . . . . . . . . . . . . . . . . . .6
SET THE CONTROL CONFIGURATION
SWITCHES/JUMPER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
WIRE THE SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Select and Wire the Transformers to the Control Panel . . . .8
Install the Model 8570 Thermostats and Wire to the
Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Wire the HVAC Equipment to the Control Panel . . . . . . . .10
Wire the Zone Dampers to the Control Panel . . . . . . . . . .12
Wire a Plenum Sensor to the
Control Panel – OPTIONAL . . . . . . . . . . . . . . . . . . . . . . . .12
Wire an Outdoor Sensor to the
Control Panel – OPTIONAL . . . . . . . . . . . . . . . . . . . . . . . .13
Wire an Aprilaire Automatic Humidifier Control (AHC)
to the Control Panel – OPTIONAL . . . . . . . . . . . . . . . . . . .14
Wire an EAC, ERV or Ventilation Damper to the
Control Panel – OPTIONAL . . . . . . . . . . . . . . . . . . . . . . . .15
START UP AND TEST . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
SEQUENCE OF OPERATION . . . . . . . . . . . . . . . . . . . . . . .22
Automatic Changeover . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Initial Power Up or Reset . . . . . . . . . . . . . . . . . . . . . . . . . .22
Damper Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Heating Equipment Outputs – Configured for
HEAT/COOL Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Heating Equipment Outputs – Configured for
HEAT PUMP Operation . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Emergency Heat Equipment Outputs – Applies Only
When Configured for HEAT PUMP Operation . . . . . . . . . . .25
Cooling Equipment Outputs . . . . . . . . . . . . . . . . . . . . . . . .25
EAC Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
ERV/Vent Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
AHC Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
CONTROLS:
• Up to four zones
• Separate two-stage heating and two-stage cooling
equipment
• Two stage heat pumps with one stage of auxiliary heat
• Energy Recovery Ventilators or Model 6506 Ventilation
Damper
• Electronic Air Cleaners
• 2-wire or 3-wire dampers
REQUIRES:
• Two 24-volt transformers: one for control panel and
thermostats, and one for dampers
• One Aprilaire Model 8570 Thermostat per zone
• Standard thermostat wire
OPTIONAL:
• Plenum Temperature Sensor (Aprilaire Model 8052)
• Model 56 Aprilaire Automatic Humidifier Control
• Outdoor Temperature Sensor (Aprilaire Model 8052 – not
needed if installed with an AHC)
INTEGRATES WITH:
• Aprilaire Automatic Humidifier Control (AHC) to enhance
humidity control
• Aprilaire Model 8570 Thermostat

3
WARNINGS AND CAUTIONS
WARNING
1. 120 Volts may cause serious
injury from electrical shock.
Sudden operation may cause
serious injury from moving parts.
Leave power disconnected until
installation is complete.
2. Sharp edges may cause serious
injury from cuts. Use care when
making duct openings and
handling ductwork.
3. The Aprilaire Zoned Comfort
Control System is designed for
indoor use only. Do not expose
any component of the zone
control system to moisture. Do
not mount any Aprilaire Zoned
Comfort Control equipment
where it may be accessible to
children.
CAUTION
1. Turn off the HVAC system power before removing or installing any wires
into the terminals of any component on the system. Wiring with a live
circuit can lead to electrical shorts that can damage components.
2. Installation must be done in accordance with all applicable codes.
3. Installer should touch a grounded metal object before handling the
Aprilaire control panel to avoid potential loss of internal computer
programs due to static discharge.
4. A zoned comfort control system may not control temperature properly
unless the heating and cooling system is properly sized and balanced.
5. Insufficient air flow or excessive temperatures through the heating and
cooling system could result in equipment damage. Refer to the
manufacturer’s recommendations for minimum safe airflow and
temperature requirements.
6. Excessive pressure across a bypass evaporative type humidifier may cause
high air velocity in the humidifier, resulting in water being blown into the
ductwork. Refer to the Design Guide form 5001 for humidifier installation
considerations.
7. Install an outdoor thermostat to prevent non-seasonal equipment starts.
8. Do not mount the control panel on any part of the heating/cooling
equipment or ductwork.
9. Do not install control panel where temperatures exceed 140°F (60°C) or
are below 32°F (0°C).
10. Improper system installation could cause water damage from frozen
pipes. Check system operation after installation.
SPECIFICATIONS
ELECTRICAL ENVIRONMENTAL
Operating Temperature 32°F (0°C) to 140°F (60°C)
Operating Humidity up to 90% non-condensing
Shipping Temperature -40°F (-40°C) to 180°F (82°F)
Control Panel Input Voltage 20-30 VAC
Power Requirement
(control panel & thermostats only) 40 VA
Max. current through EAC terminals 1 amp @ 24 VAC
Max. current through ERV/Vent terminals 1 amp @ 24 VAC
Max. current through 1 amp each or 3 amp
equipment control terminals total @ 24 VAC
Damper Voltage 18-30 VAC
Damper Fuse 3 amp, fast acting
Outdoor Temperature Sensor RPC Model 8052
Plenum Temperature Sensor RPC Model 8052

4
CONTROL PANEL LAYOUT (See Figure 1)
(1) 24 VAC power input serves
thermostat and AHC connection.
(2) POWER LED light blinks at once per
second with power applied unless
put in Test Mode when it blinks
twice per second.
(3) Four sets of thermostat inputs.
H (eat) LED lights when the
thermostat calls for heating, C (ool)
LED lights when calling for cooling,
F (an) LED lights when calling for
continuous fan and the LINK LED is
lit continuously when a thermostat
is connected.
(4) LEDs for all HVAC Equipment
outputs.
(5) Visible (with the cover on) LEDs to
indicate when the system is Heating,
Cooling or operating the Fan.
(6) Separate power input for 2 or
3-wire dampers.
(7) ZONE LEDs light when the Normally
Open (NO) contact is closed.
(8) Automatic Humidifier Control
connection; LINK LED lights when
the AHC is communicating to the
control panel.
(9) HUM LED lights when the
Humidifier valve is on.
(10) Outputs for ERV/Ventilation and
Electronic Air Cleaner (EAC) control.
(11) LED indicates when ERV/Vent or
EAC relay is closed.
(12) Dip switch settings to configure
HVAC outputs, activate/deactivate
ERV/Vent outputs and set period
and frequency for ventilation control.
(13) Jumper to turn on/off EAC control.
(14) Inputs for an outdoor temperature
sensor and plenum temperature
sensor.
(15) Test button runs automatic test
sequence. Reset button momentarily
breaks power to control panel
microcontroller.
FIGURE 1

5
RUN WIRE FOR THE SYSTEM (See Figure 2)
FIGURE 2
Single-Stage Two-Stage Boiler w/AC Radiant 1st Stage Heat, Single-Stage Two-Stage
System Type Furnace & A/C Furnace & A/C (2-xformer) Furnace 2nd Stage Heat & A/C Heat Pump Heat Pump
Wires 465 5 57
TABLE 1 – WIRES REQUIRED FOR VARIOUS HVAC EQUIPMENT TYPES
WIRE TYPE: Standard 18-24 gauge stranded or solid thermostat wire can be used for all wire runs.
IMPORTANT
Avoid running thermostat, AHC and sensor wires along side line voltage wires to prevent electrical noise on the Intelligent
Zoned Comfort Control system.
Model 8570 Thermostat
Model 6504 Control Panel
Zone Dampers
Plenum or Outdoor
Temperature Sensor
Automatic
Humidifier Control
Energy Recovery Ventilator or
Ventilation Control Damper
HVAC
Equipment
Electronic
Air Cleaner
4 wires
(1000 ft. max.)
4 wires
(300 ft. max.)
See
Table 1
2 or 3 wires
2 wires Future
Connection
2 wires

6
MOUNT THE CONTROL PANEL (See Figure 3)
FIGURE 3
CAUTION
Electrostatic discharge can damage the control. Touch a grounded metal object before touching the circuit board, and
then only touch the circuit board on the edges when handling.
• Do not mount directly on foundation walls or on the HVAC equipment or ductwork. These locations can cause moisture to
condense on the control panel.
• Mount indoors, in a location where the temperature will not exceed 140°F (60°C) or drop below 32°F (0°C).
1. Press in the cover latch on the left side of the enclosure and pull open the cover.
2. There are six (6) keyholes on the base of the enclosure. Use the four that are visible with the circuit board in place.
3. Use #8 screws (field supplied) to mount the base.
If space limits the use of the outside keyholes, the circuit board must be removed from the base to use the two center keyholes.
a. Carefully remove the screw securing the circuit board to the base.
b. Flex back the retaining clips holding the top of the circuit board to release.
c. Re-install the circuit board after mounting the base.
D4
D3 D6D5
D13
D15
c 2004 Research Products Corp.
F1
C6
+
R12
R34
R26
R21
R30
R27
R31
R33
R35
R37
R41
R46
R52
R39
R42
R47
R56
R53
R55
R59
R61
R63
R49
R48
R45
R44
R62
R60
R58
R57
R50
R51
R54
R68
C15
R32
C31
J11
J8
R15
R5
RST
J10
K7
J9
R80
U1
K2
J12
C19
U11
R85
K12
C9
R75
R24
R79
F2
R6 C14
U3
R11
JP3
C13
K6
R10
J1
C40
R16
W1
SW5
C20
PURGE
NO
ERV
C34
/
140
VNT
EAC
DAMPERS
R
R
R
ZB
40
C
D7
C
ZA
ZB
ZA
U10
C
R
ZB
ZA
C
C3
ZA
R
ZB
ODT
Plenum
ODT
R83
C
I-
I+
R78
R1
R25
ELEC.
170
45
C32
GAS
PURGE
MULTI-STAGE
OFF
VENT
HC
HP
ERV
ON
SNGL
K1
CD
CD
AB
K11
AB
CD
DC
AB
A
R36
B
RESET TEST
# of ZONES USED
# of ZONES STAGED
PLENUM SENSOR
HIGH LIMIT
LOW LIMIT
VENT TIME
K8
ON
ERV/VNT
EQUIP.
VENT CYCLE
B2203429 Rev. 3
C29
OFF
EAC
R87
C
5VDC
1
24VDC
REG.
GND.
MFG.
R
LINK
D28
F
C
H
D29
ZONE 4
ZONE 3
ZONE 2ZONE 1
AHC
D30
LINK
F
C
D31
H
LINK
F
C
C41
H
LINK
F
C
H
FAN
Y1
Y2
W1
W2
B
SW6
O
Sensor
MAIN
AGND
TEST
J3
D32
R76
RV1
D33
D34
K10
R43
R18
D35
C25
C22
D36
D37
+
C35
Q1
Y1
J2
C33
+
J13
R22
Q2
R28
C7
+
C39
R81
R19
K9
U2
D38
SW1
C23
C38
U5
+
C42
D39
C21
R8
C1
C16
R74
L1
K4
C11
R20
D26
D40
C8
+
C24
D41
D46
SW2
C2
K5
SW3
J7
21
1
61
U8
41
J5
O
W2
B
RC
Y2
Y1
RH
G
R65
J6
R82
C12
R13
R67
R9
JP1
C17
R84
C30
JP2
R29
D42
R77
R7
K3
R23
D43
U6
C36
R14
R86
C10
C18
C27
+
U7
R3
C37
R4
C26
J4
R17
R69
U9
K14
K15
K16
R73
K13
D44
D45
R72
R71
R70
C5
C4
D47
D20
R40
R64
R66
C28
U4
R38
SW4
D1
D2
D8
D9
D11
D12
D14
D16
D17
D18
D19
D21
D22
D23
D24
D25
D27
AHC
LINK
EAC
HUM
TEST
ZONE 1
COOL
ZONE 2
ZONE 3
ZONE 4
HEAT
ERV/VENT
iHVAC
On
ZONE 4
ZONE 3
ZONE 2ZONE 1
24VAC DAMPER
RCCOMNCNOCOMNCNOCOMNC
NO
COM
NC
POWER NO
Mounting Keyholes
(2 located under
circuit board)
Cover Latch
Circuit Board
Retainer Screw
Retaining
Clips

7
SET THE CONTROL CONFIGURATION SWITCHES/JUMPER (See Figure 4)
EAC ON or EAC OFF – In the future, the Aprilaire Model 5000 will be capable of wiring directly to the 6504.
Alternative wiring options do currently exist – contact the factory and request Diagram 30-293. Set the jumper to the
top two pins if EAC control is desired.
SINGL(E) OR MULTI-STAGE – Set to SINGL if the heating and cooling
equipment or heat pump is single stage.
ERV/VNT: ON/OFF – If you want the control panel to control an energy
recovery ventilator or a ventilation damper, turn this switch on.
ERV/VNT: ERV/Vent – To control an ERV, set the switch to ERV. To control a
ventilation damper, set to Vent (ERV/VNT ON/OFF switch must be set to ON
for this switch to have any function).
HC EQUIP or HP (Heat Pump) – If controlling a heat pump, set to HP. If
controlling separate source heating and cooling equipment, such as a furnace
and air condition or roof top unit, set to HC EQUIP.
Plenum Sensor: 40° or 45° Low Limit – Set the temperature at which the
cooling outputs will be turned off to prevent coil freezing. (Requires an
Aprilaire Model 8052 Plenum Sensor.)
Plenum Sensor: 140° or 170° High Limit – Set the temperature at which
the heating outputs will be turned off to prevent overheating. (Requires an
Aprilaire Model 8052 Plenum Sensor.)
ELEC or GAS – Set to ELEC if the G terminal is to be energized with W1/W2
heating outputs.
NO PURGE or PURGE – Set to NO PURGE if the HVAC equipment has a built in purge, where the blower continues to operate,
after a cooling call for a specific amount of time. Set to PURGE to allow the control panel to control this purge cycle.
# of ZONES USED – Set the number of zones that will be wired to the control panel.
# of ZONES STAGED – Set to something other than 1 if it is desired to allow staging (and subsequently increased airflow) only
when 2, 3 or 4 zones are calling, and at least one of those zones are calling for second stage heating or cooling.
VENT TIME – Sets the amount of time that the ERV will operate or the Ventilation Damper will be open during the Vent Cycle.
VENT CYCLE – Sets the period over which the amount of ventilation run time will be summed. For example, if the Vent Time is
set for 30 minutes and the Vent Cycle is set for 1 hour, the ERV or Ventilation Damper will be operated for 30 minutes per hour.
15 minutes 30 minutes 45 minutes 60 minutes
1 Hour 2 Hours 3 Hours 4 Hours
1 Zone 2 Zones 3 Zones 4 Zones
1 Zone 2 Zones 3 Zones 4 Zones
IMPORTANT: This must be set properly for the system to operate.
FIGURE 4

8
SELECT AND WIRE THE TRANSFORMERS TO THE CONTROL PANEL
WIRE THE SYSTEM
WARNING
120-volts may cause serious injury from electrical shock. Sudden operation may cause serious injury from moving parts.
Leave power disconnected until installation is complete.
1. Two separate 24-volt transformers will be required for the system. The HVAC equipment transformer can not be used for
power. Transformer #1 is used to power the control panel, thermostats and humidifier. Transformer #2 is used to power the
zone dampers and Ventilation Damper.
2. Size Transformer #1.
• If an Aprilaire Automatic Humidifier control (AHC) will be part of the system, install a 50 VA transformer.
• If an AHC will not be part of the system, install a 40 VA transformer.
3. Install Transformer #1 (see Diagram 1). The load side (24-volt side) of Transformer #1 is wired to the 24 VAC terminals
of the control panel.
4. Size Transformer #2.
• Add all the zone dampers that are in the system.
• Subtract the number of dampers in the zone with the least
number of dampers.
• This is the most number of dampers that could be energized
at one time. Multiply this number by 10.
Example: If you have a 4-zone system, and there are two
dampers per zone in all but one zone that has only one damper
(7 total dampers in the system), then the total number of dampers
that could be energized at one time is: 7 - 1 = 6 dampers.
• Add 10 VA if a Ventilation Damper will be powered from this
transformer. In the example above you would need 70 VA to
power the zone dampers (60 VA) and the Ventilation Damper
(10 VA), so use a 75 VA transformer.
5. Install Transformer #2 (see Diagram 1). The load side
(24-volt side) of Transformer #2 is wired to the DAMPER POWER
terminals of the control panel.
6. If multiple transformers are required for damper power,
refer to the “Wire the Zone Dampers to the Control Panel”
section on page 12.
Component Component VA Required
Control Panel and up to Four Thermostats 40 VA
AHC and Humidifier 10 VA
Zone Damper 10 VA each
Ventilation Damper (Aprilaire Model 6506) 10 VA
DIAGRAM 1

9
INSTALL THE MODEL 8570 THERMOSTATS AND WIRE TO THE CONTROL PANEL
DIAGRAM 2 – MODEL 8570 THERMOSTAT (shown with enclosure face removed)
TERMINALS
R= 24-volt (hot)
C= 24-volt common
ZA, ZB = Information
terminals
1. Run wire between the thermostat and control panel. Use standard 4-conductor, 18-24 gauge thermostat cable.
The maximum wire length is 1000 feet. Do not run wire along side line voltage (110-volt) wire.
2. Install the thermostat base according to the instructions supplied with the thermostat.
Make the wire entry hole in the wall as small as possible to prevent drafts into or out from the inside of the wall.
3. Install the wires in the
thermostat terminals as shown
in Diagram 2. Use the same
wire colors for the terminals at
each of the thermostats for
consistency – this will help to
ensure a successful start up.
4. Set the 6504/AHC dip switch
(see Figure 5) located on the
thermostat circuit board to the
6504 position, and set the other
dip switches to match what
was set on the control panel
dip switches.
5. Install the wires in the control
panel terminals as shown in
Diagram 2.
ON
HEAT / COOL
GAS
MULTI
6504
HEAT PUMP
ELEC
AHC
SINGLE
IMPORTANT NOTE: Always wire to the lowest
numbered zones on the control panel. If there are
only three zones, wire to Zone 1, Zone 2 and Zone 3.
DO NOT SKIP A ZONE – the system will not
operate correctly if zones are skipped.
FIGURE 5

10
WIRE THE HVAC EQUIPMENT TO THE CONTROL PANEL
WARNING
120-volts may cause serious injury from electrical shock. Sudden operation may cause serious injury from moving parts.
Turn off power to HVAC System and leave power disconnected until installation is complete.
1. Disconnect power to the HVAC system.
2. Run wire between the HVAC equipment and the control panel. Use the appropriate number of conductors for your application.
Standard 18-24 gauge thermostat cable can be used.
3. Set the HVAC equipment configuration switches to match your application (see “Set the Control Configuration
Switches/Jumper” on page 7).
4. Use the diagram that is appropriate for your application to terminate the wires to the HVAC equipment and the HVAC
EQUIPMENT terminals of the control panel. (Refer to Diagrams 3-8.)
DIAGRAM 3 – Single-Stage Furnace and A/C DIAGRAM 4 – Two-Stage Furnace and A/C
TERMINAL DEFINITIONS
Y1 = 1st-stage cooling
Y2 = 2nd-stage cooling
W1 = 1st-stage heating
W2 = 2nd-stage heating
G= Fan
TERMINAL DEFINITIONS
Y1 = 1st-stage cooling
W1 = 1st-stage heating
G= Fan

11
DIAGRAM 5 – Boiler and A/C DIAGRAM 6 – Radiant Floor First-Stage Heat,
Furnace 2nd-Stage Heat and A/C
DIAGRAM 7 – Singe-Stage Heat Pump DIAGRAM 8 – Two-Stage Heat Pump
TERMINAL DEFINITIONS
Y1 = 1st-stage compressor
W1 = 2nd-stage heat & emer.
heat (auxiliary heat)
G= Fan
O= Reversing valve
(cooling)
TERMINAL DEFINITIONS
Y1 = 1st-stage compressor
Y2 = 2nd-stage compressor
W1 = 3rd-stage heat & emer.
heat (auxiliary heat)
W2 = Emergency heat
G= Fan
O= Reversing valve (cooling)
TERMINAL DEFINITIONS
Y1 = 1st-stage cooling
W1 = 1st-stage radiant
floor heat
W2 = 2nd-stage furnace heat
G= Fan
TERMINAL DEFINITIONS
Y1 = 1st-stage cooling
W1 = 1st-stage
boiler heat
G= Fan

12
WIRE THE ZONE DAMPERS TO THE CONTROL PANEL
1. Run 2-wire thermostat cable
to normally open or normally
closed dampers. Run 3-wire
cable for power open/power
close dampers. Multiple dampers
for the same zone can be daisy
chained together.
2. Wire the dampers to the Zone
Damper output terminals on the
control panel (See Diagram 9):
NC – This terminal remains
energized when that zone
thermostat is calling for
heating/cooling/fan or when no
zone is calling. This terminal is
used to power a damper open.
NO – This terminal energizes in a non-calling zone when another zone thermostat makes a call for heating/cooling/fan.
This terminal is used to power a damper closed.
COM – This terminal provides a common connection for the NC and NO terminals.
3. If multiple transformers will be required, wire them in parallel as shown. Before wiring the transformers together,
ensure that they are connected in phase by observing polarity marks or terminal orientation on each transformer.
DIAGRAM 9
WIRE A PLENUM SENSOR TO THE CONTROL PANEL – OPTIONAL
1. Locate the Aprilaire Model 8052 sensor in the supply trunk, after the heat exchanger
and cooling coils and before the zone dampers (see the shaded areas of Figure 6).
2. Mount the sensor according to the installation instructions provided with the sensor.
3. Before wiring to the control panel, measure the resistance across the sensor.
The resistance corresponds (approximately) to the sensed temperature according to
the following table:
4. Wire the sensor to the control panel PLENUM SENSOR terminals. THIS MUST BE
DONE BEFORE POWER IS APPLIED TO THE CONTROL PANEL or the sensor will not be
recognized by the control panel.
IMPORTANT
Do not mount the sensor in direct line-of-sight of the heat exchanger, cooling coils or UV lights as this may cause the
sensor to report false temperature readings.
FIGURE 6 – Furnace Setup
Temperature (°F) 30 40 50 60 70 80 90 100
Resistance (kΩ)34.6 26.1 19.9 15.3 11.9 9.4 7.4 5.9 Locate
sensor
in shaded
area.

13
WIRE AN OUTDOOR SENSOR TO THE CONTROL PANEL – OPTIONAL
Temperature (°F) 0 102030405060708090100
Resistance (kΩ)85.4 62.6 46.3 34.6 26.1 19.9 15.3 11.9 9.4 7.4 5.9
NOTE: If an outdoor sensor is wired to the control panel, it will override the temperature provided by the AHC, if an AHC
will be part of the installation. Outdoor temperature is transmitted to all the connected thermostats to be shown on the
display, is used for ventilation control and is used for balance point control on heat pump applications.
1. Mount the Aprilaire Model 8052 sensor (see Figure 7).
• Locate on the North, side of the building if possible. East and
West are acceptable locations as long as the sensor will not
be exposed to direct sunlight.
• Mount above anticipated snow line.
• Mount at least 3 ft. away from exhaust vents and
condensing units.
• Maximum wire length from sensor to thermostat is 300 feet.
• Under a soffit or under a wall overhang are recommended
areas for mounting the sensor.
2. Run a 2-wire cable from the sensor to the control panel.
3. Take a resistance measurement before connecting to the ODT terminals of the control panel to verify the sensor is
properly installed. Measure the resistance at the control panel to account for wire splices. The resistance will depend on
the outdoor temperature:
4. Wire the sensor to the ODT terminals of the control panel.
NORTH, EAST
OR WEST SIDE
OF BUILDING
SENSOR WITH
BRACKET
ABOVE SNOW LINE
FIGURE 7

14
WIRE AN APRILAIRE AUTOMATIC HUMIDIFIER CONTROL (AHC) TO THE CONTROL PANEL – OPTIONAL
The AHC must be the type that has the “CHANGE WATER PANEL” LED on the front and has the front access door for wiring
(knob does not need to be removed to access the wiring terminals).
Information is shared between the AHC and the control panel. The AHC provides indoor humidity, outdoor temperature and
humidifier valve status (on/off) to the control panel. The control panel tells the AHC when the heat is on or when continuous fan
is on, eliminating the need for a Model 50 relay or use of equipment humidifier (HUM) terminals. The control panel also supplies
power to the AHC. The control panel will distribute outdoor temperature to be displayed on the thermostats and will use outdoor
temperature for ventilation control and high and low balance point control in heat pump applications.
NOTE: If an AHC is installed, do not wire an outdoor temperature sensor to the ODT terminals of the control panel.
1. Install the Automatic Humidifier Control and its outdoor temperature sensor:
• Follow the directions provided with the AHC except do not mount the AHC temperature sensor in a fresh air intake.
To ensure accurate measurement, the temperature sensor must be mounted outside.
• Maximum wire length from AHC to the control panel is 300 feet.
• Power the AHC through the 6504 Control Panel as shown. DO NOT power the AHC through furnace accessory terminals.
• DO NOT operate the AHC in Manual Mode – this will result in the outdoor temperature shown on the thermostats
to always be 20°F.
2. Run a 4-wire cable from the AHC to the control panel – maximum wire length is 300 feet.
3. Wire the AHC to the control panel – see Diagram 10. Use wire color as a means to ensure the terminals are connected correctly.
4. After completing the Model 6504 installation, you will need to verify proper operation of the AHC – see AHC installation
instructions for details on how this is done.
DIAGRAM 10

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WIRE AN EAC, ERV OR VENTILATION DAMPER TO THE CONTROL PANEL – OPTIONAL
To control an electronic air cleaner (EAC), ventilation damper or an energy recovery ventilator (ERV), 24-volt control will be
required. The EAC relay closes whenever the HVAC equipment is operating (heating, cooling or continuous fan – see sequence of
operation for details). The ERV/VNT relay closes in accordance with the amount of time set on the VENT TIME and VENT CYCLE
dip switches – see sequence of operation for details.
EAC OR ERV INSTALLATIONS – REQUIRES 24-VOLT CONTROL
1. Mount the EAC or ERV in
accordance with the installation
instructions provided with the unit.
2. Run a 2-wire cable from the
24-volt control of the device to
the control panel.
3. Connect the wires to the 24-volt
control of the device.
4. For EAC control – connect the
other end of the wires to the EAC
terminals on the control panel
(see Diagram 11).
• Set the EAC ON/OFF jumper to
the ON position as shown in
Diagram 11.
5. For ERV control – connect the
other end of the wires to the
ERV/Vent terminals on the
control panel (see Diagram 12).
• Set the ERV/Vent switches as
shown in Diagram 12.
DIAGRAM 11
DIAGRAM 12
Contact the factory and request diagram 30-293 to control
an Aprilaire Model 5000 Electronic Air Cleaner.
Contact the factory and request diagram 30-293 to control
an Aprilaire Model 8100 Energy Recovery Ventilator.

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MODEL 6506 VENTILATION CONTROL DAMPER INSTALLATIONS
Control of a ventilation damper requires a 24-volt power source, which can be taken from the zone damper power input terminals.
It also requires an AHC or an outdoor temperature sensor – see sequence of operation for details.
1. Install the Aprilaire Model 6506
Ventilation Damper, into a fresh air
intake duct in accordance with the
instructions provided with the damper.
2. Run a 2-wire cable from the ventilation
damper to the control panel.
3. Wire the ventilation damper according
to Diagram 13. Set the ERV/Vent
switches as shown in Diagram 13.
4. Set the Ventilation Time and
Ventilation Cycle dip switches to
meet ventilation needs.
DIAGRAM 13
House Size Bedrooms
(square feet) 2345
1000-1500 15 30 30 30
1501-2000 30 30 30 30
2001-2500 30 30 30 30
2501-3000 30 30 30 45
3001-3500 30 30 45 45
TABLE 2 – RECOMMENDED SETTINGS FOR VENTILATION CONTROL
Ventilation Time Setting (minutes/hour)
As an example, for a 2,500 square foot home with 3 bedrooms set the Vent Time switches for 30 minutes and the Vent Cycle
switches for a one-hour cycle.
NOTES:
Based on ASHRAE 62.2 ventilation requirement.
Based on fresh air duct of 20’ long flex duct, 0.08 in. w.c. static pressure at fresh air duct. A longer fresh air intake duct or lower
return static will increase the Ventilation Time required. Additionally, local codes may affect the settings.
Based on the default setting of one hour Cycle Time. Use Cycle Time settings of 2, 3 or 4 hours where longer run times or less
frequent operation is preferred. Adjust Ventilation Time accordingly. (In the above example set the Ventilation Time to 50 minutes
and the Cycle Time to 2 hours.)

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START UP AND TEST
1. Before applying power to the control panel or the HVAC equipment, perform the
following inspections:
• Make sure that the “# of ZONES USED” dip switches are set correctly for your
installation and that the thermostat inputs for the lowest numbered zones are used.
For example if there are two zones in your system, set the “Number of Zones” dip
switches for 2 zones, then wire to the Zone 1 and Zone 2 thermostat inputs.
# of ZONES USED
• Verify that the 6504/AHC dip switch is set to 6504 on all thermostats.
• Verify that the following dip switches are set correctly and are the same on the
control panel and the thermostats:
– Heat/Cool or Heat Pump
– Single or Multi-Stage
– Electric or Gas
• Use wire colors to verify wiring to each thermostat terminal in each zone.
2. Power up the control panel transformer – do not power the HVAC Equipment.
• Powering the control panel will initiate an addressing sequence that will cause the
LEDs at each zone to blink in sequence – this is normal. After power up, or whenever
the RESET button is pressed, the control panel goes through the addressing sequence.
The sequence takes approximately 5 seconds to complete.
3. Verify that the “LINK” LED at each set of wired thermostat inputs is lit continuously.
If one or more of the “LINK” LEDs is not lit, is blinking or if all LEDs are blinking then return
to step 1. If all are on, then continue with step 4.
1 Zone 2 Zones 3 Zones 4 Zones
SYMPTOM CAUSE
Not all of the zones were included
in the addressing sequence
# of ZONES USED dip switch is not set correctly – change setting and press
the RESET button.
All of the LEDs in a zone
are blinking
Corrupt response or no response from a thermostat. Make sure the smallest
numbered zones are used, verify that wiring is correct, and that the thermostat
6504/AHC dip switches are set to 6504. Press the RESET button.
The LINK LED is blinking Heat/Cool or Heat Pump dip switch on this thermostat does not match what
was set on the control panel. Set the thermostat or the control panel dip
switch to the correct setting, then press the RESET button.
The LINK LED in a zone is not lit # of ZONES USED dip switches not set correctly – change setting and press
the RESET button.
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4. Power up the damper transformer.
5. Auto Test
Auto Test allows you to turn on/off all of the outputs without having to go to the thermostats to make calls for heating, cooling
or fan. Auto Test will turn on and off all of the outputs that have been configured to be available. If, for example, the EAC
and ERV/Vent outputs are not turned on by their respective dip switch, or an AHC has not been installed, then these steps are
skipped in the Auto Test sequence. Similarly, if the dip switches have been set for single stage operation, then second stage
outputs will not be turned on.
BEFORE STARTING AUTO TEST, DETERMINE IF THE HVAC EQUIPMENT POWER IS TO BE TURNED ON AND CLOSE
FURNACE/AIR HANDLER ACCESS DOORS. As stated, the outputs will turn on/off, so, for example, if you do not want to have
the compressor turn on with the control panel outputs, do not turn on the power to the condensing unit. Each step will last for
one minute, or until the next press of the TEST button.
To Auto Test, repeatedly press the TEST button on the control panel to cycle through the steps shown in Table 3. You have one
minute to check that the outputs are functioning before Auto Test times out. If it times out before desired, simple repeat the
Auto Test. Press the TEST button to cycle to the next step. After the final step, all thermostat LEDs will blink to indicate that
Auto Test has been completed, after which the panel will reset.
Auto Test is only available the first four minutes after power up or after pressing the RESET button on the control panel.
Step Output Relays Closed LEDs ON (see Figure 8) Step skipped if…
(see Figure 8) Thermostat Equipment Side Panel
1 B none B none
2 EAC none B EAC EAC ON/OFF pin jumper
in OFF position
3 ERV/Vent none B ERV/Vent ERV/Vent ON/OFF
dip switch set to OFF
4 B none B HUM AHC has not been installed
5 B, W1 Zone 1-4 “H” B, W1 HEAT
6 B, W1, W2 Zone 1-4 “H” B, W1, W2 HEAT SINGL/MULTI-STAGE
dip switch set to SINGL
7 B none B none
8 G Zone 1-4 “F” B FAN ON
9 B none B none
10 O, Y1 Zone 1-4 “C” O, Y1 FAN ON, COOL
11 O, Y1, Y2 Zone 1-4 “C” O, Y1, Y2 FAN ON, COOL SINGL/MULTI-STAGE
dip switch set to SINGL
12 B none B none
13 ZONE 1 NO (damper) none B ZONE 1
14 ZONE 1,2 NO (dampers) none B ZONE 1 & ZONE 2 # of ZONES USED
set to 1
15 ZONE 1-3 NO (dampers) none B ZONE 1 – ZONE 3 # of ZONES USED
set to 1 or 2
16 ZONE 1-4 NO (dampers) none B ZONE 1 – ZONE 4 # of ZONES USED
set to 1, 2 or 3
17 B none B none
TABLE 3 – AUTO TEST SEQUENCE

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FIGURE 8 – Control Panel Layout

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OUTDOOR
TEMPERATURE
UP (▲) AND
DOWN (▼) BUTTONS
MULTI-FUNCTION
BUTTONS
FIGURE 9
6. Reapply power to the HVAC equipment if not already done prior to Auto Test (step 5).
7. Verify that the AHC or outdoor temperature sensor has been installed correctly.
• The thermostat display will be similar to Figure 9. The time and date, mode of operation, temperature settings and fan
status may be different.
• To check the AHC or outdoor temperature sensor, at one of the thermostats, look for the outdoor temperature on the display.
SYMPTOM CAUSE
Auto Test did not start No power – apply power to control panel.
Auto Test is only available the first four minutes after power up – press the
RESET button and try Auto Test again.
EAC or ERV/Vent output
and LED did not activate
Outputs not configured to be on – use jumper/dip switches to turn EAC ON
or ERV/VENT ON.
AHC LED did not light or
HUM LED did not light
No AHC detected:
• Apply power to AHC or ensure power supplied to AHC is continuous.
• Verify wiring is correct.
W2 or Y2 outputs
did not energize
Configured for single-stage operation – change SINGLE/MULTI dip switch position.
Not all of the damper
outputs were energized
Not configured for correct number of zones – see NO. OF ZONES dip switch.
TROUBLESHOOTING GUIDE