Honeywell DB7110U User Manual

DB7110U Universal Heat Pump

MENU

SETTING

SYSTEM

FAULT

M37637

DB7110U-DEFROST CONTROL

Defrost Controller

INSTALLATION INSTRUCTIONS

APPLICATION

The DB7110U Universal Heat Pump Defrost
Controller is a heat pump defrost control used in
single stage heat pump appliances. This product
replaces over 260 OEM and competitive controls and
can be easily programmed to meet the requirements
of virtually any single stage heat pump. See Table 2,
“Compatibility Chart.,” on page 5.

FEATURES

The DB7110U provides:

• Universal defrost control for single stage heat
pumps

• LED display for easy setup and configuration

• Small, square footprint for easier installation

• Demand and timed defrost modes

• System status and fault indication

• Selectable reversing delay to limit noise when
going in and out of a defrost cycle

• Fault history for easy troubleshooting

SPECIFICATIONS

Electrical Ratings

Input Voltage: 24VAC, 60Hz

Max. Input Current: 200mA

Compressor Contactor: 1A @ 24VAC

Outdoor Fan:

1/2HP motor
5A full load, 30A locked rotor, 240VAC.

Aux Heat: 1A @ 24VAC

Reversing Valve: 1A @ 24VAC

All outputs rated for 100,000 operations.

All terminals except FAN-IN and FAN-OUT are NEC
Class 2 low voltage.

Environmental Ratings

Operating Temperature Range: -40F to 150F

Humidity Limits: less than 95% (non-condensing)

Fig. 1. DB7110U1000.

INSTALLATION AND CONFIGURATION

Overview

When Installing This Product…

1. Read these instructions carefully. Failure to fol-

low instructions can damage the product or
cause a hazardous condition.

2. Check ratings given in these instructions and
on the product to make sure the product is suit­able for your application.

3. Installer must be a trained, experienced service
technician.

4. Use these instructions to check out the product
operation after installation.

34-00032-01

DB7110U UNIVERSAL HEAT PUMP DEFROST CONTROLLER

WARNING

WARNING

M37663

M37664

Electrical Shock Hazard. Can cause severe
injury, death or property damage.

Disconnect power supply before beginning
installation to prevent electrical shock or
equipment damage. More than one disconnect
may be involved.

Control Location

1. Before removing the old control, make note of

the wire connections to ensure the wires will be
connected to the correct terminals of the
DB7110U.

2. Mount DB7110U inside the junction box on the
outdoor unit using the two included self-drilling
sheet metal screws.

3. Use the control as a template to drill new mount­ing holes if necessary.

4. If the mounting tabs interfere with other compo­nents in the junction box, break/cut off the
unused mounting tabs prior to tightening the
mounting screws.

Coil Sensor Location

Fig. 2. Coil Sensor.

1. The outdoor coil sensor must be used. Without

the coil sensor, the DB7110U cannot determine
when to defrost. The coil sensor included with
the DB7110U replaces the existing defrost ther­mostat or coil sensor installed on the unit.

2. Place the sensor on the coil where the OEM sen­sor/thermostat was located. If replacing a
defrost thermostat, note the original settings for
proper adjustment of the termination and
enable temperatures on the DB7110U. They are
often marked with their open and close points. A
thermostat marked L60-25F for example would
correspond to a Termination Temperature of
60degF and an Enable Temperature of 35degF
(60deg-25deg).

3. If the location of the OEM sensor/thermostat is
inaccessible or difficult to access, place the new
coil sensor on the coil loop nearest the expan­sion valve where refrigerant is entering the coil
during the heating mode. This location gives the
largest temperature difference between the air.

4. Ensure the coil sensor is clamped tightly to the
coil. It may be desirable to add insulation to the
sensor to yield more accurate readings,
although this is generally not needed.

Wiring

SENSOR

M37638

Fig. 3. Coil Sensor Mounting.

OUTDOOR AIR SENSOR LOCATION

Fig. 4. Air Sensor.

1. The outdoor air sensor is optional. Using the

outdoor air sensor will enable the DB7110U to
implement a more advanced defrost algorithm
that determines to defrost based on the relation­ship between coil and air temperatures. Without
the air sensor, the DB7110U defrosts when the
coil temperature is below the Enable Tempera­ture for the Defrost Cycle Time. It is advisable to
use the air sensor if possible as it may reduce the
number of unnecessary defrosts that are com­mon among defrost timers.

2. Mount the air sensor such that the capsule is
hanging in air near the outdoor coil.

3. Do not locate the air sensor too close to the coil
that sensor readings are influenced by it.

4. Do not mount the air sensor in direct sunlight.

5. The air sensor capsule should not be in contact

with metal or some other material that may
change its readings.

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 ter­minals, wire nut them to the included wiring pig­tails. Do not crimp terminals to solid wire.

34-00032—01 2

DB7110U UNIVERSAL HEAT PUMP DEFROST CONTROLLER

A

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

AIRCOIL

IF THE PRESSURE SWITCH(ES) ARE IN SERIES
WITH THE CONTACTOR, JUMPER THE
ONBOARD CONNECTIONS. DO NOT BYPASS
ANY PROTECTIVE PRESSURE SWITCHES.

M37758

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.

Name Function

R (24V) 24V Hot

C (COM) 24V Common

W Aux/emergency heat request from

Y Compressor request from

O Reversing valve request from

HPC
(2 Terminals)

LPC
(2 Terminals)

AUX Output to auxiliary/emergency heat

COMPR
(2 Terminals)

RV
(2 Terminals)

thermostat – W requests will cause
the AUX output to be energized.

thermostat – Y requests will cause
the COMPR and FAN terminals to be
energized.

thermostat – controls the status of
the RV output.

High pressure cutout/switch – these
terminals must be shorted for
compressor operation. Never

bypass protective pressure
switches.

High pressure cutout/switch – these
terminals must be shorted for
compressor operation. Never

bypass protective pressure
switches.

– energized during a defrost cycle or
when requested by W input.

Output to compressor contactor –
energized by Y request.

Output to reversing valve –
energized by O input and as
required by a defrost cycle.

INDOOR

EQUIPMENT

UX

R

C

O/B

W

Y

Fig. 6. Wiring diagram for systems with no low

DB7110U

FAN-OUT

FAN-IN

RV

COMPR

HPC

LPC

AIRCOIL

pressure switch.

OUTDOOR

EQUIPMENT

FAN

REVERSING

CONTACTOR

PRESSURE

(OPTIONAL)

SWITCH

SENSOR

SENSOR

L2

L1

VALVE

HIGH

AIR

COIL

M37757

OUTDOOR

EQUIPMENT

FAN

REVERSING

CONTACTOR

PRESSURE

PRESSURE

(OPTIONAL)

SENSOR

L2

L1

VALVE

HIGH

SWITCH

LOW

SWITCH

AIR

SENSOR

COIL

INDOOR

EQUIPMENT

AUX

R

C

O/B

W

Y

Fig. 5. Wiring diagram with pressure switches

DB7110U

FAN-OUT

FAN-IN

RV

COMPR

HPC

LPC

AIR

COIL

connected to defrost control.

Fig. 7. Wiring diagram for systems with pressure

switches in series with the contactor and no

connection to the defrost control.

M37756

3 34-00032—01

DB7110U UNIVERSAL HEAT PUMP DEFROST CONTROLLER

M37640

CURRENT MODE OF OPERATION
OFF, HEAT, COOL, DELAY, ETC.

OUTDOOR COIL TEMPERATURE
DEGREES FAHRENHEIT

OUTDOOR AIR TEMPERATURE
DEGREES FAHRENHEIT

INDOOR

EQUIPMENT

AUX

R

C

O/B

W

Y

DB7110U

FAN-OUT

FAN-IN

RV

COMPR

HPC

LPC

AIRCOIL

WHEN THE COMPRESSOR CONTACTOR IS POWERED DIRECTLY
FROM THE Y TERMINAL, SET THE REVERSING DELAY AND SHORT
CYCLE DELAY TO 0.

HIGH

PRESSURE

SWITCH

PRESSURE

SWITCH

OUTDOOR

EQUIPMENT

IF THE PRESSURE

SWITCH(ES) ARE IN SERIES

WITH THE CONTACTOR,
JUMPER THE ONBOARD

DO NOT BYPASS ANY

PROTECTIVE PRESSURE

LOW

FAN

L2

L1

REVERSING

VALVE

CONNECTIONS.

SWITCHES.

COIL

SENSOR

CONTACTOR

M37759

Fig. 8. Wiring diagram for simple timer applications.

CONFIGURATION

1. Connect power.

2. On power up the display will briefly flash the

software version of the DB7110U and then begin
cycling between the normal operating screens
showing the current mode and the values of the
two temperature sensors. Note that there is brief
startup delay following power up where com­pressor operation is prohibited.

Fig. 9.

The displayed coil and air temperature readings
can be very useful for optimizing and trouble­shooting defrost performance.

3. There are several configurable options to opti­mize defrost performance. See “User Interface”
on page 7 for a detailed description of each
parameter/screen. Press the select (o) button
advance through the various screens and  and
 buttons to adjust the various parameters.
Table 4 below describes each parameter.

CHECKOUT

1. After the startup delay has expired, generate a

request for heat by shorting R to Y (and R to O if
configured as a “B” system, reversing valve ener­gized in heating mode).

2. Verify the compressor, fan, and reversing valve (if
applicable) are energized.

3. Press and hold the  button until “tESt” appears
on the display as shown below.

M37641

Fig. 10.

4. Verify the unit enters defrost mode

de Fr

M37642

Fig. 11.

The reversing valve will change states and the
aux heat will be energized. A few moments later
the fan will be turned off. If Reversing Delay is
enabled, the compressor will be turned off for
the selected time, and then turn back on to
reduce noise.

The DB7110U will remain in defrost for at least
one minute. After one minute has elapsed, the
DB7110U will exit defrost after the coil tempera­ture has risen above the termination
temperature or after the selected defrost time,
whichever comes first.

Test mode can be terminated at any time by
pressing and holding the  button again.

34-00032—01 4