Master Bilt Master Controller 2.0 User manual

Master Controller 2.0
Reverse Cycle Defrost System
Installation & Operations Manual
An Electronic Microprocessor- ased
Electric Expansion Valve Refrigeration Control System
With TCP/IP Internet Monitoring Feature
January 2012
PN 888-88889

2
IMPORTANT NOTICES
• Read this manual before installing your Master Controller 2.0
system. Keep the manual and refer to it before doing any service on
the equipment. Failure to do so may result in personal injury or
waive warranty of damaged equipment.
• Modifications to existing equipment are subject to approval by Master-
Bilt and must be explicitly written. There are no implied flexibilities
designed into this product.
• The following points apply unless overwritten and approved by the
Master-Bilt engineering department
o Maximum distance of wires between the evaporator and the
Master Controller 2.0 MUST not exceed 40 ft.
o The Master Controller 2.0 MUST be mounted on the
neighborhood of the vestibule entrance door for below -40
o
F extra
low temp freezer
o All sensor wires MUST be in separate metal conduit from power
wiring and control wiring for below -40
o
F extra low temp freezer
• Due to continuous product enhancements, Master-Bilt reserves the right
to make engineering changes and change specifications for product
improvement without notice.

3
INTRODUCTION...................................................................................................................4
WARNING LABELS AND SAFETY INSTRUCTIONS...........................................................5
APPLICATIONS ....................................................................................................................5
MASTER CONTROLLER......................................................................................................6
Description .................................................................................................................6
Factory-Mounted Parts ...............................................................................................8
Features .....................................................................................................................9
Sequences of Operation...........................................................................................10
START UP .........................................................................................................10
OFF MODE .........................................................................................................10
COOL MODE ......................................................................................................10
DEFROST MODE .................................................................................................11
Scheduled Defrost ......................................................................................11
Demand Defrost ........................................................................................11
Manual Defrost ..........................................................................................12
COIL DRAIN MODE ...............................................................................................12
FAN DELAY MODE ...............................................................................................12
SAFETY MODE ....................................................................................................12
Multiple Evaporator Configuration ............................................................................13
BOND CONTROLLERS FROM FRONT PANEL ..............................................................13
PEER TO PEER MODE ..........................................................................................13
ALTERNATING MODE ...........................................................................................14
Definition of On-Board Symbols ...............................................................................14
STATUS, DEFAULT AND READING DISPLAY ...............................................................14
ALARM DISPLAY .................................................................................................17
Setting Parameters by On-Board Pushbuttons ........................................................17
Temperature Sensors...............................................................................................19
SENSOR SERVICE INSTRUCTIONS ..........................................................................19
Pressure Transducer ...............................................................................................20
Charging the Master Controller 2.0 Refrigeration System .......................................21
Technical Notes........................................................................................................22
REVERSE CYCLE DEFROST ...........................................................................................23
General Information..................................................................................................23
Advantages ..............................................................................................................23
Factory-Installed Parts..............................................................................................23
Eliminated Parts .......................................................................................................24
Defrost Time.............................................................................................................24
Charging a Master Controller 2.0 System Equipped with Reverse Cycle Defrost ...24
ELECTRIC WIRING............................................................................................................24
TYPICAL WIRING DIAGRAMS ............................................................................................25
TYPICAL SET POINTS FOR CONTROLLER.....................................................................28
TROUBLESHOOTING GUIDE............................................................................................29
Troubleshooting Electric Expansion Valve ..............................................................30
MASTER-BILT PART NUMBERS .......................................................................................30

4
INTRODUCTION
Thank you for purchasing a Master-Bilt Master Controller 2.0 Reverse Cycle Defrost system. This manual
contains important instructions for installing, using and servicing the system as well as a parts list. Read this
manual carefully before installing or servicing your equipment.
DANGER
Improper or faulty hook-up of electrical components of the refrigeration units can result in severe
injury or death.
All electrical wiring hook-ups must be done in accordance with all applicable local, regional or national
standards.
NOTICE
Installation and service of the refrigeration and electrical components must be performed by a
refrigeration mechanic and/or a licensed electrician.
The portions of this manual covering refrigeration and electrical components contain technical instructions
intended only for persons qualified to perform refrigeration and electrical work.
This manual cannot cover every installation, use or service situation. If you need additional information, call or
write us
Customer Service Department
Master-Bilt Products
Highway 15 North
New Albany, MS 38652
Phone [phone]
Fax [phone]
Email [e-mail]

5
WARNING LA ELS AND SAFETY INSTRUCTIONS
This is the safety-alert symbol. When you see this symbol, be alert to the potential for personal
injury or damage to your equipment. Be sure you understand all safety messages and always
follow recommended precautions and safe operating practices.
NOTICE TO EMPLOYERS
You must make sure that everyone who installs, uses or services your refrigeration is thoroughly
familiar with all safety information and procedures.
Important safety information is presented in this section and throughout the manual. The following signal words
are used in the warnings and safety messages
DANGER: Severe injury or death will occur if you ignore the message.
WARNING: Severe injury or death can occur if you ignore the message.
CAUTION: Minor injury or damage to your refrigeration system can occur if you ignore the message.
NOTICE: This is important installation, operation or service information. If you ignore the message, you
may damage your refrigeration system.
The warning and safety labels shown throughout this manual are placed on your Master- ilt
refrigeration system at the factory. Follow all warning label instructions. If any warning or safety labels
become lost or damaged, call our customer service department at 800-684-8988 for replacements.
This label is on the housing of the Master Controller 2.0 typically located on an evaporator coil.
APPLICATIONS
Master Controller 2.0 Reverse Cycle Defrost systems are designed to control Master-Bilt made condensing
units and evaporators for freezer and cooler applications. Each system contains a condensing unit,
evaporator(s) with Master Controller 2.0 board(s), electric expansion valve(s), pressure transducers,
temperature sensors, reverse cycle valve and operational controls.

6
MASTER CONTROLLER
Description
The Master Controller 2.0 is a custom-designed microprocessor-based electronic controller for Master-Bilt
refrigeration products to control an electric expansion valve in response to evaporator superheat and return air
temperature. The hardware and input/output descriptions and connections of a Master Controller 2.0 are
shown below.
Figure 1 . Master Controller 2.0 Board Layout.

7
• SEI or SER Terminals. Sporlan SEI and SER type electric expansion valves are currently used for all
applications. There are 1596 nominal steps for entire valve stroke.
• Pressure Transducer is mounted at the evaporator suction header to measure saturated suction pressure in
absolute value but displayed in gauge pressure in PSIG. The suction pressure is converted to evaporating
temperature. The difference between outlet temperature and evaporating temperature is the true superheat
displayed as “SUPH”.
• Defrost Termination Temperature Sensor TS3 is mounted downstream of the distributor tube after the valve
and close enough to the evaporator coil to measure defrost termination temperature during defrost cylce. Figure
2 on the previous page shows the sensor locations of the evaporator and the controller.
• Outlet/Fan Cut-In Temperature Sensor TS1 is mounted on the suction line about 6” to 10” away from the
evaporator to measure outlet temperature during cooling cycle and to serve as evaporator fan cut-in temperature
sensor. The sensor is at a 2 or 10 o’clock position on the suction line. The default value of the fan cut-in
temperature is pre-set at 20
o
F for commercial refrigeration application.
• Room Temperature Sensor TS2 is typically mounted with a plastic tie at the drain pan on the side of the
evaporator return air. It is located around the middle of the evaporator to allow even air flow across it. If
necessary, it can be relocated to a spot with better representation of the cold room temperature.
• Four Digit LED Display is used to show status of the controller, set point values and temperatures.
• Green Amber and Red LED Status Indicators. The green LED will be on when the compressor relay is
energized. The green LED will blink when the air temperature is satisfied, but the compressor minimum run timer
or minimum off timer has not yet timed out. The red LED indicates a critical alarm has occurred (Low Pressure
alarm). The amber LED indicates all other alarms.
• Six Push uttons are used to display set points and status as well as to reset operational parameters like room
temperature, defrost mode, number of defrosts, etc. Their functions can be also performed by using the TCP/IP
interface.
• Two 20 Amp, 240 VAC NC/NO Relays. One relay is used for the defrost heater when the heater load is less
than 20 amp. It will be wired to defrost heater contactor when heater load is over 20 amp or three phase heaters.
For a reverse cycle defrost system, it is wired to a 40VA transformer that provides 24VAC power to the
reversing valve solenoid coil. The other relay is used to switch evaporator fans ON and OFF. A fan contactor
will be used if the fan motor is lager than 10 amps or three phase or the voltage is different from control voltage.
• One 3 Amp, 240 VAC NC/NO Relay is used for the compressor contactor or liquid line solenoid.
• One 3 Amp, 240 VAC NC/NO Relay is an option for an external alarm system. The customer can decide what
type of a physical alarm is used. This relay is energized when the controller is powered on. Whenever the
controller gives an alarm, the relay will be de-energized. For example, a technician can connect a phone alarm
system to this relay. When there is an alarm, the alarm system can dial in his pager or cellular phone.
• One RJ-45, TCP/IP Ehternet Port is used for Peer to Peer system or an alternating system communication
requiring ethernet connection. It is also used to communicate with a Laptop, internal network, or the internet.
• Power Input 120 or 208/240 VAC. For 120 VAC input, jumper between pins 1 and 2 o ‘Voltage Jumper’ connector and
jumper between pins 3 and 4 o ‘Voltage Jumper’ connector. For 208/240 VAC input, jumper between pins 2 and 3 o
‘Voltage Jumper’ connector.

8
Pressure
T1 T2 T3
Transducer
Valve
Electric
Liquid Line
Evaporator
De rost Temp. Sensor
Evap Coil In/
Distributor
Room Temp Sensor
Temp Sensor
Evap out / Fan Delay
Suction Line
ADVANCED MASTER CONTROLLER
Expansion
Figure 2.
Factory-Mounted Parts
• A controller board, an electric expansion valve, a pressure transducer, and three temperature sensors
for single evaporator system (standalone or alternating) or peer (multiple evaporator system)
evaporator are pre-mounted at the factory. . For a multiple evaporator system, only 1 evaporator is
required to have an air temperatue sensor. For reverse cycle defrost, a 24 VAC 40VA transformer is
mounted at standalone or master evaporator to provide power 24VAC to the four-way reversing valve
mounted in the condensing unit. The control circuit and power supply are pre-wired to the terminal
board of the evaporator. The board is molded in epoxy to avoid excessive moisture in cold room.
• A 4-way reversing valve, operating at 24 VAC, is installed in a reverse cycle defrost equipped unit. A
transformer is also installed in one of the evaporators to supply 24VAC to the 4-way reversing valve.
• Peer to Peer controls can be connected directly to each other, using a CAT-5E cable, if there are only
2 controllers. The controllers must be connected through an Ethernet switch or router if 3 or more
controllers are on the system. The controllers must be bonded together. A technician should install the
CAT-5E cable from the controllers to the Ethernet switch or router and bond the controllers. All
components are factory tested. A technician should check all the wiring and settings for proper
operation after installation.

9
Features
• One of the most energy-saving features of the Master Controller 2.0 Reverse Cycle Defrost system is
free floating head pressure. A head pressure control is not installed on Master Controller 2.0 systems.
Without this control, compressors work at the highest efficiency at the lowest possible condensing
pressure rather than at the limited pressure level typically found in conventional systems using a head
pressure control valve for low ambient environments. For more energy saving information, go to
www.master-bilt.com/pdfs/master_controller_vs_standard_system.pdf.
• The electric expansion valve replaces a thermal expansion valve. The refrigerant flow of the electric
expansion valve is modulated by the true superheat, or the difference of evaporator outlet and
evaporating temperatures.
• The room temperature sensor replaces the conventional temperature control. The temperature is set
with the pushbuttons on the Master Controller 2.0 board or through the web page. The default
temperature must be checked during the first startup of the machine against actual application
temperature. Default must be re-set to actual application temperature if there is a discrepancy.
• The on-board timer is used for run time control and scheduling defrosts. No mechanical defrost timer is
necessary for this system. Once the power is turned on, the timer starts counting.
• The Master Controller 2.0 has the capability to perform scheduled defrost or demand defrost
o When the scheduled defrost scheme is chosen, the on-board timer is used for scheduled
defrosts. The system works in the same fashion as a regular conventional system with
mechanical defrost timer.
o When the demand defrost is chosen, the controller will not initiate a defrost unless it is needed.
The low temperature system is pre-set with demand defrost.
• The demand defrost scheme is a pioneer design by Master-Bilt for freezer applications. Extensive lab
tests indicate that many unnecessary defrosts are eliminated and energy consumption reduced when
using demand defrost compared to using a conventional refrigeration system equipped with a
mechanical defrost timer.
• The operational status of modes, room temperature and alarms is displayed on the four-digit on-board
display.
• Manual defrost is available on standalone and Peer to Peer systems.
• All components are factory-mounted, pre-wired and tested to save on-site installation labor and reduce
chance of installation errors.
• The superheat set point has a wide adjustability range 5° to 20
o
F. This range allows the controller to
meet different customers’ needs, and require less refrigerant charge for winter operation than
conventional refrigeration unit when no head pressure valve is installed in the condensing unit.
• The controller can be used in low, medium and high temperature applications. The internal
programming will recognize the input of room temperature set point (RMSP) and automatically select
appropriate segments of the program for the application.
• The patented reverse cycle defrost control (United States Patent 7,073,344) reduces defrost energy
usage by up to 80% and decreases defrost time from 20-45 minutes (freezer equipped with electric
heaters) to 3-5 minutes in a freezer or 1
1
/
2
– 2 minutes in a cooler with a completely clean defrost.
• Maximum operating suction pressure can be controlled by the electric expansion valve eliminating the
crankcase pressure regulator for some applications.
• Minimum operating suction pressure provides additional compressor protection.

10
Sequences of Operation
START UP
When power is applied to the board, the controller closes the valve. The controller will display ‘STUP’ on its
four-digit display for five seconds. It will then display ‘CKFN’ on the four-digit display for 10 seconds. The
evaporator fans will be on for the first 15 seconds allowing a service technician time to check them. The
controller will then turn the fans off and check each sensor. The controller will check the pressure transducer
for a short or open. It will display ‘CKPR’ on the four-digit display for three seconds. If the sensor fails, the
controller will display an alarm and go to safety mode for a failed sensor. If the sensor passes, it will display
‘OKPR’ on the four-digit display for three seconds. The controller will check the sensor connected to ‘TS1’ for a
short or an open. It will display ‘CKT1’ on the four-digit display for three seconds. If the sensor fails, the
controller will display the alarm ‘STSA’ on the four-digit display and go to safety mode for a failed suction
sensor. If the sensor passes, it will display ‘OKT1’ on the four-digit display for three seconds. The controller will
check the sensor connected to ‘TS2’ for a short or an open. It will display ‘CKT2’ on the four-digit display for
three seconds. If the sensor fails, the controller will display the alarm ‘ATSA’ on the four-digit display and go to
safety mode for a failed air sensor. If the sensor passes, it will display ‘OKT2’ on the four-digit display for three
seconds. The controller will check the sensor connected to ‘TS3’ for a short or an open. It will display ‘CKT3’ on
the four-digit display for three seconds. If the sensor fails, it will display the alarm ‘CTSA’ on the four-digit
display and go to safety mode for a failed coil temperature sensor. If the sensor passes, it will display ‘OKT3’
on the four-digit display for three seconds. If all sensors pass, the controller will display ‘CKFH’ on the four-digit
display for six seconds.
The controller will not go into defrost during the preceding start up procedure. It will check the number of
defrosts per day (DFPD) and time_of_day (HOUR, MIN). If it is time for the controller to be in defrost, it will start
in DEFROST mode. If not, the controller will start in COOL(REFR) mode after fan delay.
The set points are stored in EEPROM (Electrically Erasable Programmable Read Only Memory). Batteries
are not required to store the new set points. If power is lost, the set points which were in the controller at that
time will be used when power is restored.
OFF MODE (OFF)
The controller starts in OFF mode by fully closing the valve. The controller will keep the valve closed for the
minimum OFF Time (MOTM) in order to keep the compressor in pumpdown or off for a minimum amount of
time.When the room temperature reaches the cut-in set point (room temperature set point “RMSP” plus the
temperature difference set point “ADIF”), the controller goes to COOL mode (REFR).
If a scheduled defrost scheme is selected, while the controller is in OFF mode, it is constantly checking the
number of defrosts per day and the time_of_day and calculating the time for defrost. When the time_of_day is
right for a defrost, it will immediately go into DEFROST mode right after the current OFF mode.
If the demand defrost scheme is selected, defrost will be checked and initiated only during the COOL
mode.
After the Minimum OFF Time is timed out and the room temperature reaches the Cut-In temperature, the
controller will go into COOL mode(REFR).
While in OFF MODE, the four-digit display on Master will show ‘OFF’ for three seconds, ‘RMTP’ for two
seconds, and the numerical display of the room temperature for five seconds. The four-digit display on
controllers without an air temperature sensor will show ‘OFF’.
COOL MODE (REFR)
The controller starts COOL mode by opening the valve. The condensing unit will start by a suction line low
pressure control cut-in. The electric expansion valve is modulated by the controller so that a preprogrammed
superheat set point is maintained during the refrigeration process. Actual superheat is the temperature
difference of the evaporator outlet and the evaporating temperature converted from the reading of the
presssure transducer, or T
out
-T
sat
. The controller will keep modulating the valve so the superheat will equal the
superheat set point. Meanwhile, the controller reads also the room air temperature TS2. When the room
temperature is below the room temperature set point (pre-set to -10
o
F for low temp), it goes back to OFF
mode. All the time that the controller is in COOL mode, it is constantly checking the criteria to determine if a
defrost should be initiated. It will immediately go into DEFROST mode (DEFR) when defrost criteria are met.

11
If the suction pressure is above the maximum operating pressure set point (MOP), the valve will modulate
to control the pressure at or below the maximum operating pressure set point (MOP). When the operating
suction pressure is lower than MOP, it will go back to superheat control. Suction pressure is used to calculate
saturated temperature (TSAT).
If the suction pressure is below the Minimum pressure set point (MNPR), the valve will close and the
control signal to the external relay will be turned off. It will resume normal operation when the pressure is
above the Minimum pressure set point.
While in COOL MODE, the four-digit display on Master will show ‘REFR’ for three seconds, ‘RMSP’ for two
seconds, and the numerical display of the room temperature for five seconds. The four-digit display on
controllers without an air temperature sensor will show ‘REFR’.
DEFROST MODE (DEFR)
There are two methods to determine if a defrost will be initiated for the Master Controller scheduled defrost
and demand defrost. If the number of defrosts per day ‘DFPD’ is set to 0, the controller will do the demand
defrost by default. If the number of defrosts per day ‘DFPD’ is set from 1 to 8, the controller will do the
scheduled defrost.
Scheduled Defrost
The following is the description of the scheduled defrost.
The time_of_day is really an elapsed counter that counts the number of minutes that have passed. An elapsed
count of 0 is 12 00 AM. The count goes up to 1439 which corresponds to 11 59 PM. The counter then will reset
to 0.
The time of day will be kept as long as input power is connected. If input power is turned off, then back on,
the time of day will be reset to 0 which corresponds to 12 00 AM.
The first defrost start time is an elapsed time of 0 (12 00 AM). The subsequent defrost start times are
determined by adding the number of minutes between each defrost to the previous start time until there is a
defrost start time for each defrost per day. The number of minutes between each defrost is determined by
taking 1440 / number of defrosts per day as set up by the ‘DFPD’ set point.
When starting an electric defrost, FAN relay is de-energized to turn off the fans. The controller waits for five
seconds, then the DEFROST relay is energized to start a defrost.
When starting a reverse cycle defrost, the FAN relay is de-energized to turn off the fans while, at the same
time, COMPRESSOR relay is de-energized to turn off the compressor. There is a 10 second delay before the
DEFROST relay is energized to switch the four-way reverse valve. Then there is a 30 second waiting period for
pressure equalizing. Afterward, COMPRESSOR relay is energized to turn the compressor. Hot gas will be
reversed to flow to the evaporator while the electric expansion valve is modulated to start a defrost.
The controllers use the coil sensor ‘TS3’ as the defrost termination sensor. When this temperature gets
above the preprogrammed Defrost Termination Set Point (DTSP) before the preprogrammed Maximum
Defrost Time (MXDT), the defrost will terminate. Otherwise, it will be terminated when the Maximum Defrost
Time (MXDT) times out.
While in DEFROST MODE, the four-digit display will be ‘DEFR’ for three seconds, ‘DTTP’ for three
seconds, and the numerical display of the temperature reading from sensor TS3 for three seconds.
Demand Defrost
When ‘DFPD’ is set to ‘0’, the controller will initiate a demand defrost. The controller will not go to ‘DEFROST
MODE’ until a heavy frost accumulation is in the evaporator coil. When frost is built up in the evaporator, it will
block the air flowing through the evaporator coil and reduce the heat transfer area. It will also decrease the
evaporating temperature, which, in turn, increases probability of frosting. A demand defrost scheme to detect
the frost build-up and the criteria to start defrost are programmed in the Master Controller. Unlike scheduled
defrost, the Master Controller 2.0 with demand defrost is really an energy saver. If no selection is made, the
controller will automatically select demand defrost when the power is applied to the controller. The defrost
procedure is the same as described for the scheduled defrost.
After selecting the demand defrost, if the elapsed time since the last defrost has been a selectable time
(INTV) from 8 hours (480) to 72 hours(4320), the Master Controller 2.0 will go into defrost to ensure a proper
oil return.

12
Manual Defrost
The controller allows manually-initiated defrost when needed. The manual defrost will be disabled if the
evaporator inlet sensor detects the temperature higher than the defrost termination temperature. Operation of
the manual defrost will be discussed in a later section.
COIL DRAIN MODE (DRAN)
The controller automatically goes into COIL DRAIN whenever a defrost is terminated. The controller stays in
this mode for the preprogrammed ‘DRIP TIME’. When this time is completed the controller opens the
expansion valve and goes into FAN DELAY mode (FNDL).
While in COIL DRAIN MODE, the four-digit display on the controller will show ‘DRAN’ for five seconds,
‘RMTP’ for three seconds, and the numerical display of the room temperature for three seconds. The four-digit
display on controllers without an air temperature sensor will show ‘DRAN’.
FAN DELAY MODE (FNDL)
The controller will pull down the temperature of the evaporator without the fans on until one of the following
occurs The FAN DELAY TIME of five minutes times out or the fan cut-in sensor’s temperature (FDTP) TS1
goes below the FAN DELAY TEMPERATURE of 30 Deg F. The controller will then go into COOL mode.
While in FAN DELAY MODE, the four-digit display will be ‘FNDL’ for three seconds, ‘FDTP’ for three
seconds, and the numerical display of the temperature reading from sensor TS1 for three seconds.
SAFETY MODE
When an alarm occurs, such as a sensor failure or a communication alarm, the controller will go into ‘SAFETY
MODE’. SAFETY MODE provides minimum refrigeration to the refrigerated room before the corrective action is
taken and the alarm is cleared. The system will do the following in Safety Mode
• Pressure transducer alarm (PRSA)
o Cool mode
 Valve open for the minimum compressor run time
 Valve closed for the minimum compressor off time
 Keep doing above cycle until alarm goes away
 Ignores maximum pressure control mode
• Outlet sensor alarm (STSA)
o Cool mode
 Valve open for the minimum compressor run time
 Close valve for the minimum compressor off time
 Keep doing above cycle until alarm goes away.
o Fan delay mode
 Lets fan delay time out (five minutes)
o Defrost Mode
 If this alarm and defrost term temp sensor alarm, reverse cycel defrost will last only
three minutes with valve open;
 If this alarm and defrost term temp sensor alarm, electric defrost will last only ten
minutes with valve closed.
• Room temp sensor alarm (ATSA)
o Cool Mode
 Run on superheat control for the minimum compressor run time
 Close valve for the minimum compressor off time
 Keep doing above cycle until alarm goes away.
• Low superheat alarm (LOSH)
o Close valve and wait for alarm to go away.
• High Room Temperature Alarm (HITA)
The ‘high room temperature alarm’ occurs when the room temperature is above the preprogrammed
‘HIGH TEMPERATURE ALARM’ for a preprogrammed number of minutes. The alarm is cleared when
the room temperature is less than the ‘HIGH TEMPERATURE ALARM’ set point.
• Low Room Temperature Alarm (LOTA)

13
The ‘low room temperature alarm’ occurs when the room temperature is below the preprogrammed
‘LOW TEMPERATURE ALARM’ for a preprogrammed number of minutes. The alarm is cleared when
the room temperature is above the ‘LOW TEMPERATURE ALARM’ set point.
• Defrost term temp sensor alarm (CTSA)
o Defrost mode
 Open valve until alarm goes away or defrost terminates.
 If this alarm and outlet temp sensor alarm, defrost will last only three minutes.
 Use outlet sensor for defrost temperature termination
• Communication alarm (COMA)
o For Alternating mode, (ALTN) go to standalone mode.
o For Synchronous mode, (SYNC)
 Cool mode
• Run on superheat control for the minimum compressor run time
• Close valve for the minimum compressor off time
• Keep doing above cycle until alarm goes away.
 Pumpdown Mode
• Wait until pump down time times out.
 Drip Mode
• Wait until Drip time times out.
 Defrost Mode
• Valve will close when defrost termination temperature meets its set point if
reverse cycle defrost. Valve will close at all time if electric defrost. It will then
wait the full defrost time for other evaporators to defrost..
• If in demand defrost mode, defaults to three defrosts per day.
Multiple Evaporator Configuration
The Master Controller 2.0 can be configured with 0 to 7 other controllers. Each controller is appointed a static
I/P address at the factory for communication and sequence of operation. The evaporators are piped together to
one condensing unit. The room temperature sensor is mounted on any of the controllers. All controllers can
have a room temperature sensor connected for better control. All evaporators have a pressure transducer,
outlet sensor and coil sensor. All controllers will communicate with each other to share the room temperature
reading and the coil temperature reading. Allcontrollers will modulate its electric expansion valve independently
.
• The communication cable is a CAT/5E cable, up to 330 feet.
• Communication for peer to peer control are connected to the RJ-45 connector.
OND CONTROLLERS FROM FRONT PANEL
• Connect to Ethernet switch or router only the controllers that you want to bond.
• On any controller, using the left and right buttons, go to Manual Mode (MNMD).
• Press ‘ENTER’, display will show Password (PSWD), press ‘ENTER’
• Using the left, right, up and down buttons enter ‘0002’ and hold ‘ENTER’ button until display shows one
of the manual modes.
• Using the up and down buttons, go to ‘BOND’, press ‘ENTER’, display will show ‘ITBD’ (initialize bond).
• Press and hold the ‘ENTER’ button until display shows ‘MNMD’. After about 5 seconds, all controllers
will reset. They are then bonded.
PEER TO PEER MODE
When power is turned on, that controller will initialize itself by closing the valve. A ‘ROOM TEMPERATURE’
sensor is needed to be connected to only one Controller. A ‘ROOM TEMPERATURE ALARM’ is set only if
none of the controllers have a good air temperature sensor connected. If it does not have a room temperature
sensor connected, it will put itself in ‘COOL’ mode and wait to get the room temperature from another
controller. If it does not receive any command within a minute, it will set the ‘communication alarm’ and then

14
run in ‘SAFETY MODE’ as described previously. The ‘communication alarm’ clears when it receives any
command from that controller.
The controllers switch between ‘COOL’ mode and ‘OFF’ mode based on the warmest temperature
reading from all controllers that have a room temperature sensor.
If any controller decides to go in defrost, all controllers will then go into defrost.
If any controller decides to go in drain mode, all controllers will then go into drain mode.
If any controller decides to go in fan delay mode, all controllers will then go into fan delay mode
If there is a communication alarm at any controller, then the controller will go into defrost as a scheduled
defrost that will terminate on time only.
ALTERNATING MODE
The controller can be configured as an alternating system for dual single-evaporator refrigeration units to
provide redundancy of a refrigerated cold room. Once the network is set up, a CAT/5E cable can be connected
between the 2 controllers, connected to the RJ-45 connector. When the alternating mode is selected, the dual
refrigeration units will start pulling down box temperature to the cut-out set point then both go into OFF
MODE(OFF). When the box temperature rises up to cut-in temperature, the one of the units will come on while
the other stays off. The other evaporator will perform the refrigeration in next cooling cycle.
IMPORTANT NOTE:
In the controller, the parameter of “DFMD” has to be set for proper method of defrost. “DFMD = ELEC”
is for regular electric defrost; “DFMD = HGDF” is for regular reverse cycle defrost;
Definition of On- oard Symbols
STATUS, DEFAULT AND READING DISPLAY
When the on-board green light is on, the compressor relay is energized. When the green light is blinking, the
room temperature sensor is satisfied, but waiting for the minimum off timer or minimum run timer to time out.
When the red light is on, there is a critical alarm. When the amber light is on, there is a non-critical alarm.
The status and the digital data are displayed on the onboard four-digit LED display. Below is a list of the
parameters of the operational status.
Onboard
Four-Digit
Display Description
STUP Indicates the status of Start Up Mode
CKFN Check fan working status
CKP1 Check pressure transducer
OKP1 Indicates the pressure transducer is working as it should
CKT1 Check sensor TS1, the suction/fan cut-in temperature sensor
OKT1 Indicates the TS1 is working as it should
CKT2 Check sensor TS2, the room temperature sensor
OKT2 Indicates the TS2 is working
CKT3 Check sensor TS3, the coil temperature sensor
OKT3 Indicates the TS3 is working
CKFH Indicates all sensors are OK
FNDL Indicates FAN DELAY MODE
FDTP Actual TS1 value in FAN DELAY
COOL Indicates COOL MODE
OFF Indicates OFF MODE
PMDN Indicates PUMPDOWN MODE before an electric defrost
DEFR Indicates DEFROST MODE
DRAN Indicates COIL DRAIN MODE
DFTP Inlet sensor TS3 value in DEFROST MODE

15
A list of the parameters that can be displayed and/or changed is shown below when access to the default
settings is needed. This access is usually done by a trained technician.
Control Board
Output
RMTP
Refrigerated Room Temperature from TS2 (-60ºF to 150ºF) Displayed Value
VALV
Percentage the EEV is open (0-99%)
SUPH Actual Superheat in COOL MODE (Tout - Tsat)
TSAT
Saturated Suction Temperature calculated from Suction Pressure PRES
TOUT Evaporator Suction Outlet Temperature Sensor (TS1)
COIL Temperature read from the evaporator defrost termination sensor (TS3)
PRES
Suction Pressure read from the pressure transducer ( -14 psi to 140 psig)
STAT
RLCM
Compressor relay status On if relay is energized, OFF if relay is de-energized
RLDF Defrost relay status On if relay is energized, OFF if relay is de-energized
RLFN
Fan relay status On if relay is energized, OFF if relay is de-energized
Control Board
Output
MCTL
MVLV
Manually open the EEV a percentage(0-99%)
ALST Manually clear the alarms
OND
Manually change the control mode of the controller Go from cool or off mode to defrost mode, from defrost mode to
When controller needs to communicate with other AMC, this mode will 'bond' the controllers to communicate with each
other.
The Following display are for viewing the status of the refrigeration system and cannot be changed
The Following list indicates manual modes of the controller and may be changed for diagnostic purposes
Status of the controller REFR for cool mode, OFF for off mode, DEFR for defrost mode, DRAN for drain mode, FNDL
for fan delay mode

16
Control Board
Output
REFT Refrigerant Type (If REFT = 404A, then R-404A refrigerant, If REFT = R22, then R-22 refrigerant)
SHSP Superheat Set Point seen at the evaporator (5ºF to 20ºF)
RMSP Room Temperature Set Point or "cut-out" (-40ºF to 75ºF range)
ADIF Cut-in Temperature Differential (0ºF to 25ºF)
MOTM Minimum Time the EEV is closed, or minimum off time (0 to 15 minutes)
MRTM Minimum Time the EEV is open, or minimum run time (0 to 15 minutes)
MNPR Minimum Suction Pressure Set Point (-14.6 psi to 3.0 psig)
MOP Maximum Suction Pressure Set Point (-5.0 psi to 99.0 psig)
DFPD Number of Defrost/Day. When DFPD=0, demand defrost, when DFPD = 1-12, scheduled defrost
DFMD Defrost Mode (If DFMD = ELEC, then electric, If DMFD = HGDF, then reverse cycle, If DFMD =AIRD, then air)
INTV Only applicable when in the demand defrost scheme and RMSP <=35ºF, this Set Point designates
the time between a safety defrost. (Example; if INTV = 480, then a defrost will occur every 8 hrs (480/60).
PMDM Pump Down Timeout duration (0-5 minutes). Only applicable to elec. and air defrost schemes
DTSP Defrost Termination Temperature (40ºF to 90ºF)
MXDT Maximum Defrost Duration (10 to 99 minutes)
DRAN Drip Time Duration (0-10 minutes)
MEVM Multiple Evaporator Mode, ALTN = Alternating mode, SYNC = Peer to Peer Mode
ALSP If in alternating mode, this value indicates the number of degrees above the cut-in Set Point
(RMSP + ADIF + ALSP) at which both controllers are overridden and both go into COOL MODE.
HITA High Temperature Alarm Set Point (-35ºF to 60ºF)
HITD Temperature Alarm Delay (10 to 59 minutes)
LOTA Low Temperature Alarm Set Point (-40ºF to 55ºF)
The Following list indicates parameter values of the controller and may be changed to customize the refrigeration system

17
ALARM DISPLAY
Any alarm will cause alarm relay to switch. All alarms have a distinct display shown on the four-digit display on
the controller. The red LED will be on for a pressure or suction temperature sensor alarm and the amber LED
will on for all other alarms. Multiple alarms can exist. There is a priority as to which alarm will be displayed
before another.
Onboard
4 Digit
Display Description PRIORITY
NOAL Displays when there are no alarms.
PRSA pressure transducer 1
STSA evaporator outlet temperature sensor TS1 alarm 2
ATSA room temperature sensor TS2 alarm 3
LOSH low superheat alarm 4
HITA high room temperature alarm 5
LOTA low room temperature alarm 6
CTSA defrost termination sensor TS3 alarm 7
LPRA Low pressure alarm 8
COMA communication alarm 9
Setting Parameters y On- oard Pushbuttons
There are two levels for programming the controllers with the four-digit display and six pushbuttons. The
first level (User’s Level) will enable the USER to set the room temperature set point ‘RMSP’; the second level
(Technician’s Level) allows access to the other parameters as described above.
User’s Level Press the right or left button until ‘STPT’ (Set point) is displayed. Press the ‘ENTER’
button. If ‘PSWD’ (Password) is displayed, press the ‘ENTER’ button again. The
display should read ‘0000’ with the 0 on the right blinking. Enter the password ‘0001’
by using the up and down buttons to increment or decrement the blinking digit, and the
right or left buttons to move the blinking digit to the next digit. When the display reads
‘1111’, press and hold the ‘ENTER’ button (about 3 seconds) until ‘RMSP’ (room set
point’ is displayed. Press the ‘ENTER’ button to display the value for ‘RMSP’. If you
want to change the value, press and hold the ‘ENTER’ button until the right digit starts
blinking (about 3 seconds). Use the up and down buttons to increment or decrement
the value. Use the right and left buttons to change the digit that is blinking. When the
value that is wanted is displayed, press and hold the ‘ENTER’ button until the digit
stops blinking (about 3 seconds). At any time, pressing the ‘BACK’ button will escape
to the step before.
TECHNICIAN’s Level Press the right or left button until ‘STPT’ (Set point) is displayed. Press the ‘ENTER’
button. If ‘PSWD’ (Password) is displayed, press the ‘ENTER’ button again. The
display should read ‘0000’ with the 0 on the right blinking. Enter the password ‘0002’
by using the up and down buttons to increment or decrement the blinking digit, and the
right or left buttons to move the blinking digit to the next digit. When the display reads
‘0002’, press and hold the ‘ENTER’ button (about 3 seconds) until a set point’ is
displayed. Use the up and down buttons to get to the set point that is wanted. Press
the ‘ENTER’ button to display the value for that set point. If you want to change the
value, press and hold the ‘ENTER’ button until the right digit starts blinking (about 3
seconds). Use the up and down buttons to increment or decrement the value. Use
the right and left buttons to change the digit that is blinking. When the value that is
wanted is displayed, press and hold the ‘ENTER’ button until the digit stops blinking
(about 3 seconds). At any time, pressing the ‘BACK’ button will escape to the step
before.

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MANUAL VALVE Press the right or left button until ‘MNMD’ (Manual Mode) is displayed. Press the
‘ENTER’ button. If ‘PSWD’ (Password) is displayed, press the ‘ENTER’ button again.
The display should read ‘0000’ with the 0 on the right blinking. Enter the password
‘0002’ by using the up and down buttons to increment or decrement the blinking digit,
and the right or left buttons to move the blinking digit to the next digit. When the
display reads ‘0002’, press and hold the ‘ENTER’ button (about 3 seconds) until a
manual mode is displayed. Use the up and down buttons to get to ‘MVLV’ (manual
valve). Press the ‘ENTER’ button to display the value for the valve position. Use the
up and down buttons to increment or decrement the percentage for the valve to be
open. Use the right and left buttons to change the digit that is blinking. At any time,
pressing the ‘BACK’ button will escape manual valve mode and go back to auto mode.
If no buttons are pressed for 1 hour, the controller will go back to auto mode.
CLEAR ALARM Press the right or left button until ‘MNMD’ (Manual Mode) is displayed. Press the
‘ENTER’ button. If ‘PSWD’ (Password) is displayed, press the ‘ENTER’ button again.
The display should read ‘0000’ with the 0 on the right blinking. Enter the password
‘0002’ by using the up and down buttons to increment or decrement the blinking digit,
and the right or left buttons to move the blinking digit to the next digit. When the
display reads ‘0002’, press and hold the ‘ENTER’ button (about 3 seconds) until a
manual mode is displayed. Use the up and down buttons to get to ‘ALST’ (alarm
status). Press the ‘ENTER’ button and the display will show ‘CLAL’ (clear alarm).
Press and hold the ‘ENTER’ button until the display changes. The alarms have
cleared. At any time, pressing the ‘BACK’ button will escape this mode the previous
step.
MANUAL DEFROST Press the right or left button until ‘MNMD’ (Manual Mode) is displayed. Press the
‘ENTER’ button. If ‘PSWD’ (Password) is displayed, press the ‘ENTER’ button again.
The display should read ‘0000’ with the 0 on the right blinking. Enter the password
‘0002’ by using the up and down buttons to increment or decrement the blinking digit,
and the right or left buttons to move the blinking digit to the next digit. When the
display reads ‘0002’, press and hold the ‘ENTER’ button (about 3 seconds) until a
manual mode is displayed. Use the up and down buttons to get to ‘MCTL’ (manual
control). Press the ‘ENTER’ button to display the mode that the controller is in. To
change the mode, press and hold the ‘ENTER’ button (about 3 seconds) until the
display changes to the next mode. If the controller was in ‘COOL’ or ‘OFF’, it will go to
‘DEFR’. If the controller was in ‘DEFR’, it will go to ‘DRAN’. If the controller was in
‘DRAN’, it will go to ‘FNDL’. If the controller was in ‘FNDL’, it will go to ‘COOL’. At any
time, pressing the ‘BACK’ button will escape manual valve mode and go back to auto
mode.
OND CNTRLRS Connect the controllers that need to communicate with each other using the RJ-45
connector of the controller to an ethernet switch or router. If there are just 2
controllers, you can connect them directly, without the ethernet switch or router.
Disconnect any other controller that is not going to communicate with this
group of controllers. On any of the controllers, press the right or left button until
‘MNMD’ (Manual Mode) is displayed. Press the ‘ENTER’ button. If ‘PSWD’
(Password) is displayed, press the ‘ENTER’ button again. The display should read
‘0000’ with the 0 on the right blinking. Enter the password ‘0002’ by using the up and
down buttons to increment or decrement the blinking digit, and the right or left buttons
to move the blinking digit to the next digit. When the display reads ‘0002’, press and
hold the ‘ENTER’ button (about 3 seconds) until a manual mode is displayed. Use the
up and down buttons to get to ‘BOND’ (bond controllers). Press the ‘ENTER’ button
and the display will show ‘INBD’ (initiate bonding). Press and hold the ‘ENTER’ button
until the display changes. After 3 to 5 seconds, all connected controllers will reset.
The bonding process is complete. At any time, pressing the ‘BACK’ button will escape
this mode the previous step.

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SUCTION LINE
TEMP SENSOR
FAN DELAY
PRESSURE
TRANSDUCER
DEFROST TERMINATION
TEMP SENSOR
6" TO 10"
EVAP OUT
Temperature Sensors
The application range of the temperature sensors used for this controller is -60
o
F to +150
o
F. If the sensor
detects a temperature out of the range, an alarm will show on the controller display.
Three temperature sensors are used in the Master Controller 2.0 refrigeration system. They are the room
temperature return air sensor, the evaporator defrost termination temperature surface sensor and the
evaporator outlet (suction line) temperature surface sensor. All sensors
are solid state devices with the same characteristics that change electrical resistance in response to a change
in temperature.
The room temperature sensor is factory-mounted on the lower back of the
evaporator at the drain pan. This placement avoids heat from defrost heaters
and lights and still allows a good air stream over the sensor. Figure 3 shows a
typical mounting of the room temperature sensor.
The defrost termination sensor is mounted on one of the distributor tubes close
the coil end plate. The outlet sensor is mounted on the suction line at the outlet
of the evaporator as shown in Figure 4. These sensors are interchangeable.
SENSOR SERVICE INSTRUCTIONS
Care must be taken when brazing the suction line at the
evaporator. The outlet sensor must be taken out before brazing.
After brazing, fasten the sensor with the metal strap provided.
Make sure the sensor is tight and has good contact with the
suction line.
The temperature sensor cannot be repaired. Using the
measurements in Chart A below, you can determine if they are
functioning correctly. If the sensors are found out of tolerance,
they should be replaced.
As mentioned above, the temperature sensor changes
electrical resistance in response to temperature changes.
Disconnect the sensor from the controller, check the temperature
at the sensor location, then check and record the resistance
through the temperature sensor.
Procedures to check temperature sensor tolerance with ice water:
1. Use a cup of water with well-stirred ice. The water temperature should be an even 32°F.
2. Submerge the room temperature sensor (TS2) into the water while the Master Controller 2.0 is
normally operating. Check the display for the value. If the sensor shows 32°F, it is working properly.
3. Press the right or left buttons until the display shows the name of one of the variables. Press the up or
down buttons until the display reads ‘TCOI’, the defrost termination sensor (TS3). Press the ‘ENTER’
button to display the value. Submerge the sensor into the water. Check the display for the value. If the
sensor shows 32°F, it is working properly.
4. Scroll down the display to “TSUC”, the outlet sensor (TS1) value.
5. Submerge the outlet sensor into the water. Check the display for the value. Again, if the sensor shows
32°F, it is working properly.
Compare the temperature and resistance to Chart A.
Figure 4
Figure 3

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Chart A. Temperature/Resistance Characteristics (- 0 to 80 oF)
Temp. oF Temp. oC ohms*1k Temp. oF Temp. oC ohms*1k
-50 -45.6 43.45 15 -9.4 7.579
-40 -40.0 32.31 20 -6.7 6.731
-35 -37.2 27.96 25 -3.9 5.993
-30 -34.4 24.27 30 -1.1 5.349
-25 -31.7 21.13 32 0 .123
-20 -28.9 18.43 35 1.7 4.781
-15 -26.1 16.12 40 4.4 4.281
-10 -23.3 14.13 50 10.0 3.454
-5 -20.6 12.42 60 15.6 2.805
0 -17.8 10.94 70 21.1 2.294
5 -15.0 9.651 80 26.7 1.888
10 -12.2 8.544
NOTE: Use resistance at 32oF for sensor checking.
Pressure Transducer
Your Master Controller 2.0 will be equipped with one of two types of pressure transducer (PT). The difference
is in the color of sensor wires as noted below
New PT (19-14226, 19-14223) OLD PT (19-13955, 19-14092) Description
RED BLACK +VDC (+5)
GREEN WHITE SIGNAL (sig)
BLACK GREEN GROUND (5-)
The GROUND is connected to terminal ‘5-‘ on the board. The SIGNAL lead is connected to terminal ‘sig’ on the
board. The +VDC lead is connected to terminal ‘5+’ on the board. Chart B shows the characteristics of the
pressure transducer. NOTE: The pressure transducer cannot be repaired but replaced only.
Chart B. Pressure Sensor Simulation Values ( 0 to 1 0 PSIA)
Bar PSIA PSIG
V
(Signal to Ground)
0 0 -14.6 0.509
0.69 10 -4.6 0.784
1.379 20 5.4 1.058
2.069 30 15.4 1.332
2.758 40 25.4 1.587
3.448 50 35.4 1.862
4.137 60 45.4 2.136
4.827 70 55.4 2.391
5.516 80 65.4 2.665
6.206 90 75.4 2.920
6.895 100 85.4 3.194
7.585 110 95.4 3.469
8.274 120 105.4 3.724