18
FAN
RELAY
2ND
STAGE
HEAT
1ST
STAGE
HEAT
R
ROOF TOP UNIT
C
G
W1
W2
Y2
Y1
L1
L2
120
VAC
24
VAC
IMPORTANT!
The B terminal is for
reversing valve-heat.
DO NOT connect the
B terminal to common
side of transformer.
1ST
STG
COOL
2ND
STG
COOL
G
Y1
W1
Y2
W2
RH
RC
O
APRILAIRE MODEL
8870 THERMOSTAT
COMMUNICATION
TERMINALS
B
C
RSB
RSR
RSC
R
RSA
B+
A-
A+
B-
REF
REMOTE
SENSOR(S)
NOTE: HVAC installer may need to connect
24V AC to the R and C terminals to check
the HVAC operation. If the automation
system is to be installed after the HVAC
installation, leave the R and C terminals
connected to ensure the HVAC system
operates. If the automation system is
installed before the HVAC wiring, then
DO NOT connect HVAC wires to R and C.
SEE
NOTE
24V FIELD WIRING
FACTORY WIRING
OPTIONAL 24V
FIELD WIRING (SEE NOTE)
DIAGRAM 3 – ROOF TOP UNIT (TWO STAGE HEAT AND TWO STAGE COOL)
Summary of Contents for 8870
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