First Co EVBQ (Variable Speed) - Manual (Page 5)

from unit (as measured along the low-voltage wires), use No. 16 AWG color-coded, insulated (35 degrees C minimum) wires.
Connect low-voltage thermostat leads and low-voltage outdoor unit leads to the fan coil circuit board as shown on unit
wiring diagram. (See Figure 3.)
CAUTION: Do not use power stealing thermostats. The thermostat will cause the motor to function
improperly. A high grade digital thermostat is recommended. Failure to do so could result in damage to
components and will void all warranties.
Figure 3 - Low Voltage Wiring Connections
5
* NOTE - Some Thermostats may require a jumper between “E” and “W1”. Most Heat Pump
Thermostats have an “E” terminal for Emergency Heat. When the Tstat is switched from “Normal” to
“Emergency” the compressor circuit “Y” is locked out. Usually “E” becomes the 1st stage of heat. If
no heat call occurs on a temperature drop below set point, jumper “E” to “W” at the Tstat or at the
fan coil. If unit runs continuously on temperature rise above set point, remove jumper and refer to
the thermostat installation instructions.
Y1
W/W1
Y2
G
C
R
Y1
W1
Y2
G
C1
R
NC
HUM
Y1
Y2
R
C
DEHUM
Two Stage A/C Cooling
W/ Single Stage Heat
INDOOR
TSTAT
FAN COIL
24V
CONNECTIONS
2 STAGE
OUTDOOR
CONDENSER
Y
G
W
C
R
Y2
G
W1
C1
R
NC
HUM
Y
C
DEHUM
Single Stage A/C Cooling
W/ Single Stage Heat
INDOOR
TSTAT
FAN COIL
24V
CONNECTIONS
OUTDOOR
CONDENSER
Y
G
O/B
W
E
C
R
Y2
G
O
W1
EM
C1
R
NC
HUM
Y
O/B
W2
R
C
DEHUM
Single Stage Heat Pump
W/ Auxiliary / Backup Heat
INDOOR
TSTAT
FAN COIL
24V
CONNECTIONS
OUTDOOR
HEAT PUMP
O/B
Y1
W/W1
Y2
E
G
C
R
O
Y1
W1
Y2
EM
G
C1
R
NC
HUM
O/B
Y1
W
Y2
R
C
DEHUM
Two Stage Heat Pump
W/ Auxiliary / Backup & Emergency Heat
INDOOR
TSTAT
FAN COIL
24V
CONNECTIONS
OUTDOOR
HEAT PUMP
*
*