DB7110U UNIVERSAL HEAT PUMP DEFROST CONTROLLER
3
34-00032—01
3.
Check the line voltage connections on the fan
relay to ensure they are tight, in good connec-
tion, and more than 1/4" away from any part of
the appliance enclosure.
4.
Plug in the outdoor sensor (if used) and the coil
sensor.
5.
Reference the wiring diagrams in Figs. 5 to 8 to
aide in proper appliance wiring.
Table 1. Class 2 Low Voltage Terminations,
24V 60Hz.
Fig. 5. Wiring diagram with pressure switches
connected to defrost control.
Fig. 6. Wiring diagram for systems with no low
pressure switch.
Fig. 7. Wiring diagram for systems with pressure
switches in series with the contactor and no
connection to the defrost control.
Name
Function
R (24V)
24V Hot
C (COM)
24V Common
W
Aux/emergency heat request from
thermostat – W requests will cause
the AUX output to be energized.
Y
Compressor request from
thermostat – Y requests will cause
the COMPR and FAN terminals to be
energized.
O
Reversing valve request from
thermostat – controls the status of
the RV output.
HPC
(2 Terminals)
High pressure cutout/switch – these
terminals must be shorted for
compressor operation.
Never
bypass protective pressure
switches.
LPC
(2 Terminals)
High pressure cutout/switch – these
terminals must be shorted for
compressor operation.
Never
bypass protective pressure
switches.
AUX
Output to auxiliary/emergency heat
– energized during a defrost cycle or
when requested by W input.
COMPR
(2 Terminals)
Output to compressor contactor –
energized by Y request.
RV
(2 Terminals)
Output to reversing valve –
energized by O input and as
required by a defrost cycle.
LPC
HPC
CONTACTOR
AUX
REVERSING
VALVE
FAN-IN
FAN-OUT
R
C
O/B
W
Y
AIR
SENSOR
(OPTIONAL)
COIL
SENSOR
INDOOR
EQUIPMENT
OUTDOOR
EQUIPMENT
FAN
DB7110U
L1
L2
COMPR
RV
HIGH
PRESSURE
SWITCH
LOW
PRESSURE
SWITCH
AIR
COIL
M37756
LPC
HPC
CONTACTOR
AUX
REVERSING
VALVE
FAN-IN
FAN-OUT
R
C
O/B
W
Y
AIR
SENSOR
(OPTIONAL)
COIL
SENSOR
INDOOR
EQUIPMENT
OUTDOOR
EQUIPMENT
FAN
DB7110U
L1
L2
COMPR
RV
HIGH
PRESSURE
SWITCH
AIR
COIL
M37757
LPC
HPC
CONTACTOR
AUX
REVERSING
VALVE
FAN-IN
FAN-OUT
R
C
O/B
W
Y
AIR
SENSOR
(OPTIONAL)
COIL
SENSOR
INDOOR
EQUIPMENT
OUTDOOR
EQUIPMENT
FAN
DB7110U
L1
L2
COMPR
RV
HIGH
PRESSURE
SWITCH
LOW
PRESSURE
SWITCH
AIR
COIL
IF THE PRESSURE SWITCH(ES) ARE IN SERIES
WITH THE CONTACTOR, JUMPER THE
ONBOARD CONNECTIONS. DO NOT BYPASS
ANY PROTECTIVE PRESSURE SWITCHES.
M37758