DB7110U UNIVERSAL HEAT PUMP DEFROST CONTROLLER
3
34-00032EF—03
Wiring
WARNING
Electrical Shock Hazard. Can cause severe injury,
death, or property damage.
Disconnect power supply before beginning wiring
to prevent electrical shock or equipment damage.
More than one disconnect may be involved.
1.
Make sure the wiring complies with all local codes
and ordinances.
2.
If the low voltage wiring is bare wire with no termi-
nals, wire nut them to the included wiring pigtails.
Do not crimp terminals to solid wire.
3.
Check the line voltage connections on the fan relay
to ensure they are tight, in good connection, 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.
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)
Low 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
