Diagram 8: Two-Stage Heat Pump - Aprilaire 8570 Safety & Installation Instructions

INDOOR UNIT - AIR HANDLER
SUPPLIED JUMPER
2ND STAGE
W2
EMER. HEAT
1ST STAGE
W1
AUX. HEAT
1ST STAGE COMP. Y1
2ND STAGE COMP. Y2
FAN
G
RELAY
C
24
VAC
R
120
VAC
W1
DEFROST
Y1
1ST STAGE
COMP.
2ND STAGE
Y2
COMP.
REV.
O
VALVE
L
SERVICE
R
C

Diagram 8: Two-Stage Heat Pump

OUTDOOR UNIT - HEAT PUMP
- 16 -
APRILAIRE MODEL
8570 THERMOSTAT
W2
THERMOSTAT
W1
CONFIGURATION
RH
SWITCH SETTINGS
R
SINGLE 1 MULTI
RC
HP 2 HC
G
ELECT GAS
3
Y1
O B
4
Y2
B
O
SINGLE/MULTI – SET TO
C MULTI FOR TWO STAGE
HEAT PUMP
I+
AHC
ELECT/GAS - SET TO
CONNECTION
I-
ELECT FOR ELECTRIC
AUXILIARY HEAT , SET TO
ZB GAS FOR FOSSIL FUEL
6504
(DUAL FUEL) AUXILIARY
CONNECTION
ZA
HEAT
OUTDOOR (ODT)
GND
O/B – SET TO "O" IF HEAT
& INDOOR (IDS)
PUMP REVERSING VALVE
ODT TEMPERATURE
MUST BE ENERGIZED
SENSORS
IDS
WHEN COOLING, SET TO
"B" IF IT IS TO BE
EVENT
COM
ENERGIZED IN HEATING
TRIGGERED
NO
OUTPUT
NC
(ETO)
(6) OPTIONAL – WIRE THE EVENT TRIGGERED OUTPUT (ETO)
Terminals NO, COM and NC are the
Figure 6
Normally Open, Common and Normally
Closed outputs, respectively, of a relay
that can be used to control auxiliary
equipment. When the relay is on, a
circuit is complete between NO and
COM; when the relay is off a circuit is
complete between NC and COM. The
relay is programmed to be on or off,
with each of the programming events.
Examples of where this output might
be used include:
• Turn on outdoor ventilation for
LOAD
programming periods of the day
2A MAX OPERATING CURRENT
when the building is occupied and
3A MAX IN-RUSH CURRENT
turn it off when unoccupied.
• Have an electronic air cleaner turn
on and off only when the building is
occupied to reduce maintenance
time/cost.
MODEL 8570 THERMOSTAT
(shown with enclosure face removed)
USE ONLY TO
CONTROL 24-VOLT
LOADS
NC
COM
NO
ZA
ZB
I+
I-
IDS
ODT
GND
- 17 -
C
R
RC
RH
W1
W2
G
O/B
Y1
Y2