DB7110U UNIVERSAL HEAT PUMP DEFROST CONTROLLER
11
34-00032—01
Table 7. Sensor Diagnostics.
Table 6. Fault Code Information.
Fault No.
Description
Corrective Action
1
Internal Communication Fault
• Replace control
2
Internal Fault
• Replace control
3
Low 24V
• Measure 24V (R & C). There may be something in the
system loading the 24V transformer excessively. If voltage
is normal while the fault is currently active, replace the
control.
4
Corrupt Memory
• Reset configuration options. Replace the control if the fault
persists.
5
High Pressure Lockout – HPC
opened 3 times on a single
request.
• Investigate refrigerant charge
• Check indoor coil for blockage
• Check outdoor coil for blockage
6
Low Pressure Lockout – LPC
opened 3 times on a single
request.
• Investigate refrigerant charge
7
High Pressure Cutout is currently
open
• Investigate refrigerant charge
• Check indoor coil for blockage
• Check outdoor coil for blockage
8
Low Pressure Cutout is currently
open
• Investigate refrigerant charge
9
Coil Sensor Open Circuited
• Check the sensor hasn’t become unplugged.
• Check sensor wiring
• Replace sensor
10
Coil Sensor Shorted
• Check for pinched wires
• Replace sensor
11
Air Sensor Open Circuited
• Check the sensor hasn’t become unplugged.
• Check sensor wiring
• Replace sensor
Note that this fault will only present itself if the sensor opens
after it has been detected. It will be cleared on a reset or power
cycle. Running without an air sensor causes the control to
operate in a timed defrost mode, which may be desired
operation.
12
Air Sensor Shorted
• Check for pinched wires
• Replace sensor
Display
Description
Air sensor open circuit or unplugged
Air sensor shorted
Coil sensor open circuit or unplugged
Coil sensor shorted
A
−−
M37655
A
__
M37656
−−
C
M37657
C
M37658
__
