Johnson Controls MR2 Manual

FANs 125, 121
Temperature Controls Section A
Installation Bulletin
Issue Date 1199
© 1999 Johnson Controls, Inc. 1
Part No. 24-7664-1695, Rev. A www.johnsoncontrols.com
Code No. LIT-125194
IMPORTANT: All MR2 controls are designed for
use only as operating controls.
Where an operating control
failure would result in personal
injury or loss of property, it is the
responsibility of the installer to
add devices (safety, limit
controls) or systems (alarm,
supervisory systems) that protect
against, or warn of, control
failure.
Refer to the MR Series Refrigeration Temperature
Controls Product Bulletin, LIT-125199, for necessary
information on operation and performance
specifications for this product.
Mounting
The MR2 Control is not position-sensitive but should
be mounted for convenient wiring and adjustment.
To mount the Panel Mount version, ensure that there
is a space of at least 2-3/4 in. (70 mm) behind the
panel. Make a cutout 1-3/16 x 2-13/16 in.
(29 x 71 mm). Remove retaining clip from the control.
Insert the control into the hole. Install retaining clip and
adjust for tightness.
To mount the DIN Rail Mount version, install the DIN
rail where appropriate. Snap the control onto the rail in
position.
Wiring
!
WARNING: Shock Hazard. To avoid
possible electrical shock or
equipment damage, disconnect
power supply before wiring any
connections.
Follow these wiring guidelines:
All wiring must conform to the National Electric
Code and local regulations.
Make all wiring connections using adequate gauge
copper conductors only. Connectors are rated for
14-22 AWG wiring.
Internal to Control
V1 V2
Power
Supply Compressor
Alarm
Binary
Input
Process
Temperature
Sensor
C
A1
S1 SC DCD
Sensor
Common
Binary
Common
A2
Fr
Terminal Not Used
Refer to Rating Table
for more information.
Figure 1: MR2 DIN Rail Control
Internal to Control
V1 V2 DSC S1
Power
Supply
Binary
Input Process
Temperature
Sensor
Sensor
Common
A1
Alarm
A2
C
Compressor
Fr
Terminal Not Used
Refer to Rating Table
for more information.
Figure 2: MR2 Panel Mount Control
Canadian DOC Compliance
This digital apparatus does not exceed the Class A
limits for radio noise emissions from digital apparatus
set out in the Radio Interference Regulations of the
Canadian Department of Communications.
INSTALLATION BULLETIN
MR2 Refrigeration Temperature/Defrost Control

2A—MR2 Refrigeration Temperature/Defrost Control Installation Bulletin
Use Table 1 with function So to compensate for long
sensor leads.
Table 1: Sensor Wire Size and Length
18 AWG
20 AWG
22 AWG
Offset
300-599 ft
91-183 m
190-374 ft
58-114 m
120 -239 ft
36-73 m
1F°
1C°
600-899 ft
183-274 m
375-564 ft
114-172 m
240-349 ft
73-107 m
2F°
2C°
900+ ft
274+ m
565+ ft
172+ m
350+ ft
107+ m
3F°
3C°
Table 2: Rating Table
Rating Category
120
VAC
240
VAC
24
VDC
Horsepower
1/4
1/2
---
Full Load Amperes
5.8
4.9
---
Locked Rotor Amperes
34.8
29.4
---
Inductive (non-motor)
Amperes
8
8
8
Pilot Duty VA
275
450
---
Power source is 24 VAC. Alarms require external
power source.
FCC Compliance
This equipment has been tested and found to comply
with the limits for a Class A digital device pursuant to
Part 15 of the FCC Rules. These limits are designed to
provide reasonable protection against harmful
interference when the equipment is operated in a
commercial environment. This equipment generates,
uses, and can radiate radio frequency energy and, if
not installed and used in accordance with the
instruction manual, may cause harmful interference to
radio communications. Operation of this equipment in
a residential area is likely to cause harmful
interference, in which case the user will be required to
correct the interference at his/her own expense.
Display
Press Up and Down buttons to scroll through process
temperature, binary input status (On or OF), and
auxiliary temperature sensor reading (F2 if none). After
15 seconds of inactivity, the display shows the process
temperature.
Programming the Control
To lock and unlock the unit for programming:
Press the Enter, Up, and Down buttons
simultaneously and hold until “- - -” is
displayed. Hold for about 10 seconds until the
current temperature is displayed.
To change the setpoint:
1. Hold the Enter button for approximately
3 seconds. The display will change to
show the setpoint. Release the Enter
button.
2. Press the Up or Down button until you
reach the new setpoint.
3. Press the Enter button to save the new
setpoint.
Note: If the Enter button is not pressed after selecting the new
setpoint, the new setpoint is not saved. The control reverts
to the original setpoint.
To run the self-test procedure:
IMPORTANT: Disconnect loads before self-test
procedure. Cycle power to resume
normal operation.
Press the Up and Down buttons in sequence,
and hold for 5 seconds.
To begin a manual defrost cycle:
Hold the Defrost button for 3 seconds.
To begin a deep freeze cycle:
Press the Enter and Up buttons in sequence
and hold both for 5 seconds. The compressor
status LED will light.
To program values other than setpoint:
1. Hold the Enter button for about 10
seconds. The display changes to HY.
2. Press the Up or Down button until the
desired parameter is displayed.
3. Press the Enter button. The parameter’s
current value is displayed.
4. Press the Up or Down button until the
desired value is shown.
5. Press the Enter button to save the new
value. After 10 seconds of inactivity, the
display will return to its normal function.
Note: If the Enter button is not pressed after selecting the new
value, the new value is not saved. The control reverts to
the previous value.

A—MR2 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
Low setpoint adjustment limit
-40°F (-40°C) to HL
-25
HL:High Setpoint Stop
High setpoint adjustment limit
LL to 158 F° (158 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
di:Defrost Interval
Time between two subsequent defrost cycles; when
di=1 hour, dd cannot exceed 40 minutes
1 to 99 hours
7
dd: Maximum Defrost Duration
Defrost ends after this time; 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 cycle 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 = compressor off, alarm
on 2 = alarm on
3 = 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
SF: Sensor Failure Operation
Control function after a sensor or sensor wire failure
0 = compressor On
1 = compressor Off
2 = based on last four
cycles
2
So: Temperature Sensor Offset
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
Repair and Replacement
Field repair of the control should not be made. In
case of a defective or improperly functioning control,
check with your nearest Johnson Controls/PENN
representative.
When contacting the supplier for replacement, state
the model number of the control. This number can
be found on the data plate.

4A—MR2 Refrigeration Temperature/Defrost Control Installation Bulletin
Table 4: Error Codes and Status
Error Code (Codes will flash on the display)
System Status
F1 Open or shorted temperature sensor
Alarm output On. Compressor runs according to SF. Cycle
power to reset.
A1 Binary input open for longer than id and iF = 1
Compressor output Off. Alarm output On. Correct problem to
reset.
A2 Binary input open for longer than id and iF = 2
Alarm output On. Correct problem to reset.
A3 Binary input open for longer than id and iF = 3
Alarm output On, AH and AL disabled. Correct problem to reset.
HI Temperature has reached or exceeded
(setpoint + AH)
Alarm output On. Correct problem to reset.
LO Temperature has reached or fallen below
(setpoint –AL)
Alarm output On. Correct problem to reset.
EE Program failure
Alarm output On. Other outputs Off. Replace control.
Ordering Information
Table 5: Specifications
Power Requirements
3.7 VA @ 24 VAC 50/60 Hz, Class 2 (20-30 VAC)
Ambient Conditions
Operating 14 to 140oF (-10 to 60oC); 0 to 95% RH (non-condensing)
Storage -22 to 176oF (-30 to 80oC); 0 to 95% RH (non-condensing)
Accuracy
+1.8 Fo(+1Co)
Agency Listings
UL Recognized: File E194024, CCN XAPX2
Canadian UL Recognized: File E194024, CCN XAPX8
FCC Compliant per Class A Digital Device, Part 15
Canadian DOC Compliant per Class A, Radio Interference Regulations
Table 6: Ordering Information
Product Code Number
Description
MR2PM24-11C
MR2 Panel Mount Control; A99BB-200C sensor included
MR2DR24-11C
MR2 DIN Rail Mount Control; A99BB-200C sensor included
A99BB-200C
Replacement Sensor, cable length: 6-1/2 ft (2 m)
The performance specifications are nominal and conform to acceptable industry standards. For application at conditions beyond these
specifications, consult Johnson Controls/Penn Refrigeration Application Engineering at (414) 274-5535. Johnson Controls, Inc. shall not be
liable for damages resulting from misapplication or misuse of its products.
Controls Group
507 E. Michigan Street
P.O. Box 423 Printed in U.S.A.
Milwaukee, WI 53201 www.johnsoncontrols.com
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