A
—MR4 Refrigeration Temperature/Defrost Control Installation Bulletin
3
Table 3: Functions and Settings
Function
Description
Setting Range
Default
SI
:
Setpoint
Primary temperature setpoint at which compressor
control contacts open on temperature fall
-40 to 158°F (-40 to 70°C)
---
HY
:
Hysteresis (Differential)
Temperature difference relative to setpoint at which
compressor control contacts close on temperature rise
1 to 9 F° (1 to 9 C°)
5
LL
:
Low Setpoint Stop
High setpoint adjustment limit
-40°F (-40°C)
to
HL
-25
HL
:
High Setpoint Stop
Low setpoint adjustment limit
LL
to 158°F (70°C)
40
CC
:
Anti-short Cycle Delay
Minimum time between two compressor On cycles
0 to 9 minutes
1
Co
:
Deep Freezing Time
Time compressor forced On during deep freeze
0 to 99 minutes
60
AH
:
High Temperature Alarm
Temperature above setpoint where alarm is initiated
0 to 50 F° (0 to 50 C°)
10
AL
:
Low Temperature Alarm
Temperature below setpoint where alarm is initiated
-50 to 0 F° (-50 to 0 C°)
-10
Ad
:
Alarm Differential
Temperature difference between alarm On and Off
1 to 9 F° (1 to 9 C°)
5
At
:
Alarm Time Delay
Delay between alarm detection and activation
0 to 99 minutes
3
dF
:
Defrost Type
Select defrost type
0 = electric heater
1 = hot gas
0
dE
:
Defrost End Mode
Defrost termination type; note that defrost cycle always
ends after time set for
dd
0 = time
1 = temperature
1
dt
:
Defrost Termination
Temperature
Only used when
dE
= 1; defrost ends when
temperature reaches
dt
32 to 68°F (0 to 20°C)
55
di
:
Defrost Interval
Time between two subsequent defrost cycles; when
di
=1 hour,
dd
cannot exceed 40 min.
1 to 99 hours
7
dd
:
Maximum Defrost Duration
Defrost ends after this time, even if defrost end
temperature has not been reached; 0 disables defrost
0 to 99 minutes
45
dC
:
Dripping Time
Time compressor stopped after defrost so evaporator
can drip
0 to 99 minutes
5
dU
:
First Defrost After Power Up
Time first defrost is delayed after power up
OF
, 0 to 99 minutes
OF
(Off)
dP
:
Display During Defrost
Temperature displayed during defrost cycle
0 = last reading
1 = setpoint
0
dr
:
Display Delay After Defrost
Time after defrost before sensed temperature displays 1 to 99 minutes
20
iF
:
Binary Input Function
Configuration for normally closed binary input
0 = none
1 = compres. off, alarm on
2 = alarm on
3 = fan off, alarm on,
AH
and
AL
disabled.
0
id
:
Binary Input Time Delay
Time between binary input detection and enabling of
the function set through
iF
0 to 99 minutes
0
FF
:
Fan Operating Function
Fan operation; note that the fan is always Off during
the defrost cycle
0 = parallel with compres.
1 = always on
0
Fd
:
Fan Start-up Delay (After
Defrost)
Time after defrost that fan is switched On, even if
temperature set through
Fr
has not been reached
0 to 99 minutes
5
Fr
:
Fan Start Temperature After
Defrost End
Evaporator sensor temperature at which the fan is
switched On after a defrost cycle
-22 to 41°F (-30 to 5°C)
40
SF
:
Sensor Failure Operation
Control function after a sensor or sensor wire failure
0 = compressor on
1 = compressor off
2 = based on last 4 cycles
2
So
:
Temperature SensorOffset
Compensate for long sensor leads
-20 to 20 F° (-20 to 20 C°)
0
Un
:
Temperature Units Used
Temperature units used
0 = °C
1 = °F
1
PU
:
Display Refresh Rate
Time after which display is refreshed
1 to 99 seconds
1
