17
4. ELECTRICAL CONNECTION TO THE FURNACE
WARNING
Never connect a 120-volt AC circuit to the terminals of the furnace interlock (standard wiring). Only use the low voltage class
2 circuit of the furnace blower control.
!
For a furnace connected to a cooling system:
On some older thermostats, energizing the “R” and “G” terminals at the furnace has the effect of energizing “Y” at the thermostat and
thereby turning on the cooling system. If you identify this type of thermostat, you must use the
ALTERNATE
FURNACE
INTERLOCK
WIRING
.
S
TANDARD
FURNACE
INTERLOCK
WIRING
A
LTERNATE
FURNACE
INTERLOCK
WIRING
W
R
G
Y
W
R
G
C
Y
UNIT TERMINAL
CONNECT
OR
THERMOSTAT
TERMINALS
FOUR
WIRES
TWO WIRES
heating only
FURNACE
24-VOLT
TERMINAL BLOCK
TWO WIRES
COOLING SYSTEM
N
O
C
N
C
I O
C
OL
Y
R G B
W R G
Y
W
R
Y
R
G
Y
C
THERMOSTAT
TERMINAL
4 WIRES
2 WIRES
heating only
wiring
nuts
FURNACE
24-VOLT
TERMINAL BLOCK
2 WIRES
COOLING SYSTEM
NO
NC
C
UNIT TERMINAL
CONNECT
OR
N
O
C
N
C
I OC
O
L
Y
R G B
VE0108A
5. SPEED SELECTION
The factory set high speed value for theses units is 100 CFM, and low speed value is approximately 50 CFM. To change these values, the
transformer wire taps connections must be changed (see table and illustration below).
Speed
Connection
High Speed
100 CFM
BL-BL
85 CFM
BN-BL
Low Speed
65 CFM
GY-R
50 CFM
R-R
J14
10
9
8
7
6
5
4
3
2
1
J20
1 2
J13
ICP
A1
E
LECTRONIC
A
SSEMBLY
12
345
J12
J11
1 2
4 3 2 1
J9
J10
2 1
F1
3A
3AG T
YPE
3 2 1
JU1
M
H
4 3 2 1
5
J8
J5
J7
1
1
2
2
3
J6
1
2
J4
1
2
3
T1
24 V Class 2
9.5 V
Class 2
120 V
103 V
76 V
64 V
55 V
neutral
BK
BL
BN
GY
R
W
R
R
GY
BN
BL
BL
NC
NC
Y
Y
O
O
VE0299A
R
R
GY
BN
BL
BL
NC
NC
LOW SPEED
HIGH SPEED
C
OLOR
C
ODE
BLACK
BLUE
BROWN
GREEN
GREY
BK
BL
BN
G
GY
ORANGE
RED
WHITE
YELLOW
O
R
W
Y
NC
NO
CONNECTION
