McQuay MicroTech 200 Series User manual

Operating Manual OM 200MICRO
Group: Chiller
Part Number: 585515Y
Effective: April 2000
Supersedes: OM125
© 1999 McQuay International
200-Series MicroTech Control Panel
For Centrifugal Chillers

2OM 200MICRO
Table of Contents
Introduction......................................................................... 3
General Description ........................................................... 4
General Description...........................................................................................4
Control Panel Layout........................................................................................4
Component Description ...................................................................................6
Keypad/Display Operation............................................... 13
Menu Structure ................................................................................................17
MicroTech Status Menus ................................................. 18
Control Menu Description ............................................... 24
Alarm Menus Description................................................ 38
Master/Slave Setup.......................................................... 41
Alarms ............................................................................... 43
McQuay" and MicroTech are registered trademarks of McQuay International
1998 McQuay International
"Illustrations and information cover McQuay International products at the time of publication and we reserve the right to make changes in
design and construction at anytime without notice."

OM 200MICRO 3
Introduction
This manual provides installation, setup and troubleshooting information for the 200 Series
MicroTech control panel for McQuay centrifugal chillers. Please refer to IOMM WSCWDC for
information relating to the unit itself.
All operational descriptions contained in this manual are based on MicroTech control software
versions CFG3E04I (English) and CFG3S04I (metric). Chiller operating characteristics and menu
selections may vary with other versions of control software. Contact McQuayService for software
update information.
Installation Precautions
WARNING
Electric shock hazard. Can cause personal injury or equipment damage. This
equipment must be properly grounded. Connections to and service of the MicroTech
control panel must be performed only by personnel that are knowledgeable
in the operation of the equipment being controlled.
CAUTION
Static sensitive components. A static discharge while handling electronic circuit
boards can cause damage to the components. Discharge any static electrical charge
by touching the bare metal inside the control panel before performing any service
work. Never unplug any cables, circuit board terminal blocks, or power plugs while
power is applied to the panel.
NOTICE
This equipment generates, uses and can radiate radio frequency energy and, if not
installed and used in accordance with this instruction manual, may cause
interference to radio communications. It 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. 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 own expense.
McQuay International Corporation disclaims any liability resulting from any
interference or for the correction thereof.
Temperature and humidity considerations
The MicroTech controller is designed to operate within an ambient temperature range of -40 to +149°F
(-40 to +65.1°C) with a maximum relative humidity of 95% (non-condensing).

4OM 200MICRO
General Description
General Description
The MicroTech control panel contains a model 280 microprocessor based controller which provides all
monitoring and control functions required for the safe, efficient operation of the chiller. The operator
can monitor all operating conditions by using the panel’s built in 4-line by 40-character keypad /
display or by using an IBM compatible computer running McQuay Monitor software. In addition to
providing all normal operating controls, the MicroTech controller monitors all safety devices on the
unit and will take corrective action if the chiller is operating outside of it’s normal design conditions.
If a fault condition develops, the controller will shut the system down and activate an alarm output.
Important operating conditions at the time an alarm condition occurs are retained in the controller’s
memory to aid in troubleshooting and fault analysis.
The system is protected by a password scheme which only allows access by authorized personnel. A
password must be entered into the panel keypad by the operator before any setpoints may be altered.
Control Panel Layout
Figure 1, Major Component Locations
Terminal
Block
Low Voltage Wireway
Signal
Converter
Signal
Converter
Guardister
Board
Guardister
Board
Low Voltage Wireway
Transformer T3 Transformer T4
AOX
Board EXV
ModemLow Voltage Wireway
High
Press.
Relay
High
Press.
Relay
MCB 280
Output
Board
ADI
Board
Low Voltage Wireway
High Voltage Wireway
Terminal Block
Transformer
Circuit Breaker

OM 200MICRO 5
Features of the Control Panel
Control of leaving chilled water within a
0.2°F (0.1°C) control band.
Readout of all temperature and pressure
readings:
entering and leaving chilled water
temperature
enter and leaving condenser water
temperature
saturated evaporator refrigerant
temperature and pressure
saturated condenser temperature and
pressure - outside air temperature
(optional)
suction line, liquid line and discharge
line temperatures - calculated
superheat for discharge and suction
lines
oil sump temperature - oil feed
temperature and pressure
optional condenser heat recovery
temperature
Automatic control of primary and
**secondary evaporator and condenser
pumps.
Control of up to 4 stages of cooling tower
fans plus modulating bypass valve.
Panel mounted 12 key keypad plus 6 Quick
Access function keys. Operator can log
chiller operating conditions from a single
keypad/display instead of reading gauges,
thermometers, pots, etc. The display is a
backlit, 4 line by 40 character LCD type for
easy viewing in all lighting conditions.
New auto-logging feature will automatically
log chiller functions at the time of peak load.
The controller will store and display up to six
weeks of accumulated data.
Two levels of security protection against
unauthorized changing of set points and
other control parameters.
Complete warning and fault diagnostics to
inform operators of warning and fault
conditions in plain language. Al1 warnings,
problems and faults are time and date
stamped so there is no guessing of when the
fault condition occurred. In addition, the
operating conditions that existed just prior to
shutdown can be recalled to aid in isolating
the cause of the problem.
Eight previous faults and related operating
conditions are available from the display.
Soft loading feature reduces electrical
consumption and peak demand charges
during loop pulldown.
Adjustable load pull-down rate reduces
under-shoot during loop pulldown.
Easy integration into building automation
systems via separate 4-20mAdc signals for
chilled water reset and demand limiting.
Internal time-clock for on/off scheduling. The
time clock accommodates a 7 day schedule
plus holiday, 1 start and stop per day, and 14
holidays with programmable duration.
Communications capabilities for remote
monitoring, changing of set points, trend
logging, remote reset, alarm and event
detection, via a compatible IBM-PC running
McOuay MicroTechsoftware.
Manual control mode allows the service
technician to command the unit to different
operating states. Useful for system checkout.
BAS communication capability via McQuay's
Open Protocol strategy to over 10 major BAS
manufacturers.
Service Test mode for troubleshooting
controller hardware.
Display available in either U.S.Customary or
S.l. units. Keypad programmable alarm
contacts for normally open, or normally
closed, and optional pulse output on problem
and warning conditions.
Pressure transducers for direct reading of
system pressures. Preemptive control of low
evaporator pressure conditions to take
corrective action prior to a fault trip.
Preemptive control of high discharge
temperature.
Modulating oil cooler valve control
(optional).
Minimum vane position set point.
**Secondary throughout this publication
implies a parallel or standby pump.

6OM 200MICRO
Component Description
Microprocessor Control Board (MCB1)
The Model 280 Microprocessor Control Board
contains the electronic hardware and software
required to monitor and control the unit. It receives
input from the ADI Board and sends commands to
the Output Board to maintain the unit's optimum
operating mode for the current conditions. Status
lights are mounted on the control board to indicate
the operating condition of the microprocessor.
Pre-Start Checkout
Hexadecimal Switches
For proper chiller operation, each MicroTechcontroller must have a unique network address. The
controller’s hex switch settings define it’s location in a network as well as it’s unit type. For a stand-
alone chiller, the Hi and Lo switches should be set to 0 and 1 respectively. After changing a hex
switch setting, the controller’s power must be cycled by opening, and then closing, the panel circuit
breaker.
Note: The chiller should be in an “Off” mode before resetting the hex switch positions.
Powering the Control Panel
There are three status LED’s located on the model 280 controller which will indicate the
microprocessor’s operating condition. When power is first applied to the control panel, the red reset
LED will illuminate for approximately 3 seconds. During this time, the microprocessor is checking the
control software and performing internal hardware tests. When these tests are complete the reset LED
will turn off and the green running LED will illuminate indicating the controller’s circuitry and software
are operating correctly. The amber output 0 active LED is associated with the external alarm output.
This LED may or may not be illuminated at this time based on the setpoints under menu 36.
Figure 3, Status LEDs
If the reset LED stays on or the running LED fails to illuminate, disconnect the controller power by
opening circuit breaker CB-1 and re-check the field wiring. Observe the controller’s LED’s while re-
connecting power by closing CB-1. If the green running LED still does not turn on, a hardware failure
exists or the control software is corrupted. Downloading new control software or replacing the 280
controller should correct the problem.
Figure 2, Model 280 Microprocessor
Control Board
green
red
amber
RUNNING
RESET
ACTIVE
CPU
STATUS
OUTPUT 0

OM 200MICRO 7
With the controller powered up and the green running LED illuminated, the backlite panel on the
display module will be illuminated and the unit status menu will be visible. If the display text looks
faded or appears as “blocks” the contrast control needs to be adjusted. Watch the display and
adjusting the contrast control with a small flat-blade screwdriver until the best setting is determined.
Figure 4, Contrast Adjustment
KDI BOARD
(back side)
Power
Wiring
Ribbon
Cable
Contrast
Adjustment
The MicroTech controller contains factory installed default setpoints which will be appropriate for
most common installations. Step through all of the unit’s setpoints by using the keypad / display and
adjust them as required to meet the specific job requirements. Any faults appearing on the display
should be cleared at this time by pressing the CLEAR key.
Digital Output Board
The Output Board contains up to 24 solid state relays which are used to control the compressor,
cooling tower fans, solenoid valves and alarm annunciation. It receives control signals from the
Microprocessor Control Board through a 50 conductor ribbon cable.
Figure 5, Digital Output Board
Digital Outputs
Solid state digital relays are used to switch most of the external devices controlled by the MicroTech
panel. These devices may be pumps or solenoids that are either on or off.

8OM 200MICRO
Table 1, Digital Outputs
No. Description LED Off LED On
0 Alarm LED and Contact Programmable Programmable
1 Unload Solenoid and Front Panel LED - Unload
2 Load Solenoid and Front Panel LED - Load
3 Motor Control Relay Off On
4 Motor Control Relay Latch Unlatched Latched
5 Oil Pump Of f On
6 Oil Sump Heater Off On
7 Oil Cooler close Off On
8 Oil Cooler Open Off On
9 *Hot Gas Bypass Solenoid Off On
10 *Liquid Injection Off On
11 Cooling Tower #1 Off On
12 Cooling Tower #2 Off On
13 Cooling Tower #3 Off On
14 Cooling Tower #4 Off On
15 Evaporator Water Pump #1 Off On
16 Evaporator Water Pump #2 Off On
17 Condenser Water Pump #1 Off On
18 Condenser Water Pump #2 Off On
19 Spare
20 Spare
21 Spare
22 Spare
23 Spare
Analog/Digital Input Board (ADI)
The ADI Board provides low voltage power for the temperature and pressure sensors. It also
provides optical isolation between the Microprocessor Control Board and all 24V switch inputs.
LED's are furnished on the board to give a visual indication of the status of all digital inputs. All
analog and digital signals from sensors, transducers and switches are received by the ADI Board and
then sent to the Microprocessor Control Board for interpretation.
Figure 6, ADI Board
Analog Inputs
Analog inputs arriving at the ADI board are comprised of temperature, pressure, and flow signals. In
addition, the chiller control panel mA receive chilled water reset and demand limit signals in the range

OM 200MICRO 9
of 4-20 mA. Temperature and pressure readings have a resolution of 0.1F and 0.1 psi respectively.
Flow readings and remote reset signals are resolved to 1%.

10 OM 200MICRO
Table 2, Controller Input Signals
ADI Sensor No. Description Range
0 S00 Leaving Evaporator Water Temperature -40 - 263 F (-40-128.4°C)
1 S01 Entering Evaporator Water Temperature -40 - 263 F (-40-128.4°C)
2 S02 Compressor Suction Temperature -40 - 263 F (-40-128.4°C)
3 S03 External Chilled Water Reset (by others) 4-20mA = 0-100%
4 S04 External motor Current Reset (by others) 4-20mA = 0-100%
5 S05 Refrigerant Leak Monitor Signal (by others) 4-20mA = 0-100 PPM
6 S06 Evaporator Water Flow Transmitter Signal (by others) 4-20mA = 0-65535
7 S07 Condenser Water Flow Transmitter Signal (by others) 4-20mA = 0-65535
8 S08 Condenser Liquid Line Temperature -40 - 263 F (-40-128.4°C)
9 S09 Entering Condenser Water Temperature -40 - 263 F (-40-128.4°C)
10 S10 Leaving Condenser Water Temperature -40 - 263 F (-40-128.4°C)
11 S11 Percent Unit Amps 0-5V = 0-125% RLA
12 S12 Compressor Discharge Temperature -40 - 263 F (-40-128.4°C)
13 S13 Oil Feed Temperature -40 - 263 F (-40-128.4°C)
14 S14 Oil Sump Temperature -40 - 263 F (-40-128.4°C)
15 S15 Oil Vent Pressure 0-165 psig (0-1137.6 kPa)
16 S16 Evaporator Refrigerant Pressure 0-165 psig (0-1137.6 kPa)
17 S17 Condenser Refrigerant Pressure 0-165 psig (0-1137.6 kPa)
18 S18 Oil Feed Gauge Pressure 0-165 psig (0-1137.6 kPa)
19 S19 Transducer Power Voltage Ratio Used for Calibration
20 S20 Outdoor Air Temperature -40 - 263 F (-40-128.4°C)
21 S21 Heat Recovery Entering Water Temperature -40 - 263 F (-40-128.4°C)
22 S22 Heat Recovery Leaving Water Temperature -40 - 263 F (-40-128.4°C)
23 S23 Spare
Digital Inputs
Digital inputs indicate the status of external two-position devices such as a flow switch or remote time
clock. The ADI board senses the presence or absence of 24VAC and provides a corresponding
indication to the microprocessor control board.
Table 3, Digital Inputs
No. Description Lo Voltage Hi Voltage
0 Front Panel "Stop/Auto" Switch Stop Auto
1 Compressor High Pressure Switch Alarm Normal
2 Motor High Temperature (Guardistor) Alarm Normal
3 Vanes Closed Open Closed
4 Starter Transition - Delta
5 Starter Fault Alarm Normal
6 Evaporator Water Flow Switch No Flow Flow
7 Condenser Water Flow Switch No Flow Flow
8 Remote Start/Stop Stop Enable
9 Chiller/Templifier/Ice Chiller Templifier/Ice

OM 200MICRO 11
Analog Output Board (AOX)
The AOX board converts control instructions from the Microprocessor Control Board’s expansion
bus into an analog control signal suitable for driving a cooling tower bypass valve. Each AOX board
is factory set via jumper to provide an output signal range of 0 - 10 VDC. An additional output on the
AOX board provides an analog signal that is proportional to compressor motor current.
Figure 7, AOX Board
Analog Outputs (Optional)
The analog outputs available at the AOX board provide a variable voltage used to control field
mounted devices. The range of the output signal is jumper selectable: 0-10 VDC (default); 0-5 VDC; 4-
20 mA.
Table 4, AOX Board #1
No. Description Conversion
0 Cooling Tower Bypass Valve 0-255 : 0-100% Open
1 Proportional Motor Current Output 0-255 : 0-100% RLA
2 *Compressor Variable Frequency Drive 0-255 : 0-100% Open
3 *Cooling Tower Variable Frequency Drive 0-255 : 0-100%

12 OM 200MICRO
Signal Converter Board
The AC current signal generated by the starter is converted by the signal converter board into a 0-5
VDC signal that is directly proportional to the chiller amp draw. The amp draw signal is sent to the
ADI board for conditioning and then to the M280 controller.
Figure 8, Signal Converter Board
TB1 TB2
Guardistor Board
The Guardistor board monitors the motor winding temperature through the embedded Guardistor
sensors. If the motor temperature rises to an unsafe level, the board will signal the M280 controller
and the chiller will be shut down.
Figure 9, Guardistor Board
Power Transformers
Transformers T2, T3 and T4 provide operating power to the MicroTech controller and it’s associated
components. T2 is a conventional ferrite core transformer that converts 120VAC from the control
transformer into 24VAC. T3 and T4 are transformers that convert 24VAC from T2 into a center-tapped
18VAC.

OM 200MICRO 13
Keypad/Display Operation
The Keypad/Display is the primary operator interface to the unit. All operating conditions, system
alarms and setpoints can be monitored from this display and all adjustable setpoints can be modified
from this keyboard if the operator has entered a valid operator password.
General Description
The MicroTech keypad consists of eighteen pressure sensitive membrane switches used to step
through, access, and manipulate the information in the MicroTech controller. The selected
information is presented on a four line by forty character backlit LCD display.
The information stored in the MicroTech controller can be accessed through the keypad by following
the tree-like structure of menus and menu items. The keypad keys are divided into four groups with
four or more keys in each to ease navigation through the available menus and items.
Figure 10, MicroTech Keypad
Alarm
Stop Auto
QUICK ACCESS
Status
Control Switch
Alarm
CATEGORY MENU - ITEM ACTION
Prev.
Item
Prev.
Menu
Next
Menu
Next
Item
+
Incr.
Hel
p
Clear
Enter
=
Decr.
-
Water
Set-
points
Motor
Data Re
p
orts Oil
Temps
Refrig.
Temp’s
Pres’s
Alarm
History
Load
Unload
Figure 11, Example of a typical MicroTech display screen indicating item lines and
fields
3.Refrig Temps/Press 12:55 Mar-01-95
Saturated Evap=50.7°F/46.2psi
Suct Line= 53.1°F Li
q
Line= 87.1°F
Saturated Cond=90.8°F/105.9psi
Menu line
Item line 1
Item line 2
Item line 3
Field Two
Screen
Field One Next screen indicator
Previous screen indicator

14 OM 200MICRO
Category Group
The keys in this group provide quick access to strategic menus throughout the menu tree-structure.
This reduces the need to step through all the menus, one by one, in order to reach the desired
information.
Figure 12, Category Group
Status Key
Menus and menu items in this category provide information on the MicroTech operating conditions
and the chiller operating conditions. The entries under each menu item in this category provide
information only and are not changeable through the MicroTech keypad.
Pressing the "STATUS" key at any time shifts the display to Menu #1 which is the first menu of the
STATUS category.
Control Key
Menus and menu items in this category provide for the adjustment of all the unit control parameters.
These include capacity control, pump control and cooling tower control parameters as well as time
schedules and alarm limits. The entries under these menu items are changeable through the
MicroTech keypad.
Pressing the "CONTROL" key at any time shifts the display to Menu #11 (Control Mode) which is
the first menu of the CONTROL category.
Alarm Key
Menus and menu items in this category provide information regarding current and previous fault
conditions along with the operating temperatures and pressures at the time the fault occurred.
Pressing the "ALARM" key at any time shifts the display to Menu #27 which is the first menu of the
ALARM category.
Switch Key
Pressing the "SWITCH" key at any time toggles the display between the current menu
(Status/Control) item and the related menu (Control/Status) item somewhere else in the tree-
structure. This allows checking actual conditions against setpoints. The status menu numbers that
have related control menus are 1, 2, 3, 6 and 7. The reciprocal occurs when in the control menu,
pressing the "SWITCH" key toggles to the related status menu showing actual conditions. The
control menu numbers that have related status menus are 11, 12, 18, 19 and 22. Pressing the
“SWITCH” key the second time takes the operator back to the original menu item. For example, if this
key is pressed while the current menu item is menu item 2B (Leaving Evaporator =), the display
shifts to menu item 12B (Local Evaporator Setpoint =). This provides for easy review of actual
versus setpoint values.

OM 200MICRO 15
Menu - Item Group
Figure 13, Menu - Item Group
The keys in this group are used to scroll through the various menus and items presented on the
controller’s display. A menu contains a specific group of items.
Note: When Menu #1 is currently in the display (the first menu in the menu tree-structure), pressing
"PREV." causes an "beginning of menus" message to appear in the display.
Previous Menu
Pressing "PREV." shifts the display to the previous group of items within a menu. Note: When the first
item in a menu is currently in the display, pressing "PREV." causes an "beginning of items" message
to appear in the display.
Next Menu
Pressing "NEXT" shifts the display to the next group of items in a menu. Note: When the last item in
a menu is currently in the display, pressing "NEXT" causes and "end of items" message to appear in
the display.
Previous Item
Pressing "PREV." shifts the display to the previous group of items within a menu. Note: When the
first item in a menu is currently in the display, pressing "PREV." causes an "beginning of items"
message to appear in the display.
Next Item
Pressing "NEXT" shifts the display to the next group of items in a menu. Note: When the last item in
a menu is currently in the display, pressing "NEXT" causes and "end of items" message to appear in
the display.
Action Group
The keys in this group are for making changes to unit control
parameters or for clearing fault conditions.
Note: Before a change to a parameter can be made or before a fault
can be cleared, the display prompts the user with an "Enter
Password" message. At this point, the password must be entered
before the user can continue with the action.
Prev.
Item
Next
Item
Prev.
Menu
Next
Menu
+
Incr.
Help
Clear
Enter
=
Decr.
-

16 OM 200MICRO
Increment (+)
When changing the value of a menu item entry, pressing ''INCR. +" shifts the selected menu item to
the next higher value or next available selection.
Decrement (-)
When changing the value of a menu item entry, pressing "DECR.-" shifts the selected menu item to
the next lower value or previous available selection.
Enter (=)
Once a change has been made to a desired value, pressing "ENTER =" locks in the new value.
Help / Clear
Pressing "ALARMS" followed by "CLEAR" clears the current fault. Also, when a change is made to
a menu item, pressing "CLEAR" returns the display to the original value as long as "ENTER" has not
yet been pressed. Note: The cause of a fault should always be determined and corrected before
clearing the fault through the keypad.
Keypad Password
When changing any menu item entry (+ or- key), the user is prompted to enter a valid password. The
change will not be allowed until the correct password is entered. The password for centrifugal units is
always four successive presses of the "Enter" key.
Once this has been done, the user can make changes to menu item entries. After entering the correct
password, the controller will allow a 5 minute time period during which the operator may make any
necessary setpoint adjustments. Any keypad activity will reset the timer for the full 5 minutes so the
password only needs to be entered once per session. After 5 minutes of inactivity, the password
access time will expire providing protection against unauthorized users.
Quick Access Group
The quick access keys provide a fast shortcut directly into the most frequently used MicroTech
menus. For example, pressing the "WATER SET POINTS" key moves you directly to menu #12
without having to step through intermediate menus via the "PREVIOUS" and "NEXT" keys.
Figure 14, Quick Access Group
Display Format
The information stored in the MicroTech controller tree structure can be viewed directly on the
control panel's 4 line by 40 character display. The currently selected menu is shown on the top line
along with the current date and time. Up to six menu items may be shown on the lower three lines of
the display. Alarm menus may have an additional field on line 1.
Either English or Metric units of measure may be displayed by installing the appropriate controller
software.
Water
Set-
points
Motor
Data Reports Oil Temps
Refrig.
Temps
Press's
Oil
Temps

OM 200MICRO 17
English Customary Units:
Temperature = ºF (Fahrenheit)
Pressure = Psi (Pound per sq. inch)
Psig
Psid
Metric Units:
Temperature = ºC (Centigrade)
Pressure = kPa (Kilo Pascals)
kPag
kPda
Menu Structure
Displaying Setpoints
To view set points or operating conditions press the "PREV MENU" or "NEXT MENU" key until
menu of interest appears. (Remember pressing a key in the Category group goes to the first menu of
that group.) To view additional set points or conditions under the menu selected press the "PREV
MENU" or "NEXT MENU" key.
Changing Setpoints
Set points/values that can be modified are under the control and alarm categories. Once the menu is
selected, the set point/value can be changed by pressing the "+ INCR." or "- DECR." key. The
display screen will change and in place of the date and time the term "ENTER PASSWORD:" will be
displayed. The operator must enter the appropriate password by pressing the correct four keys in
sequence. The display will indicate "PASSWORD VERIFIED:" or ''INVALID PASSWORD:" in place of
the time and date. When the correct password is entered, the term "<Change Values Mode>" is
displayed in place of the time and date. The first value on the display that can be changed will flash
on and off. Pressing the "NEXT/ PREV MENU" or "NEXT/PREV ITEM" keys will select the next set
point/value on the screen that can be changed. Pressing the "+ INCR." or "- DECR." key will change
the numeric value or select the next option. When the correct value or option is flashing, press the
"ENTER =" key to store it into memory. The flashing will stop and the time and date is returned to the
display screen. Follow this sequence to change additional set points/values. (The term "Enter
Password" will not be displayed unless there has not been any keypad activity for flve minutes.)
Display Screen
The display screen is divided into lines and fields. The top line will indicate the menu number and a
menu description on the left side, and the time and date on the right side. The time and date will be
replaced with directions when modifying set points and values.
The first line normally will have two fields except when viewing alarms then there is a third field. Line
2 and line 3 have two fields. Different menus will have varying amounts of information and not all the
fields will be used.
When selecting new menus using the "NEXT MENU" and "PREV MENU" keys, the display is
considered screen one. If additional screens are available, there will be a arrow pointing down in the
last block in the right hand screen corner. To obtain additional information available under a specific
menu, press the "NEXT ITEM" and "PREV ITEM" keys. This will toggle between the available
screens displaying the various set points and values. Most menus will have only one screen;
however, Menu 10 (Auto Logging) has 24 screens. The range of information that can be displayed in
a field is extensive and the next section will show all possible field names, set points and values.

18 OM 200MICRO
MicroTech Status Menus
Press the "STATUS" key under the Category Group and the information in Menu 1 (Unit Status) will
be displayed. Information displayed in menus 1-10 indicates current operating conditions and cannot
be reset from the display keypad. Refer to the Metric Menu section for displays in metric values.
This menu has one screen with three lines of information. Line 1 contains the unit operating status in
field 1 and the motor % amps in field 2. Line 2, field 1 indicates the entering evaporator water
temperature and line 2, field 2 indicates the entering condenser water temperature. Line 3, field 1
indicates the leaving evaporator water temperature and line 3, field 2 indicates the leaving condenser
water temperature. This information gives the operator a quick view of the operating condition of the
unit. Pressing the switch key will toggle between this menu and Menu 11 (Control Mode). This
allows the operator to compare actual operating status versus control mode.
Menu 1, Unit Status
Item
Screen Line Display Field Range Extended Name
AllSystemsOff
Off: Alarm
Off: Ambient Lockout
Off: Front Panel Sw
Off: Remote Contacts
Off: Remote Comm
Off: Time Schedule
Off: Manual Setpoint
Off: System Comm
Start Requested
Waiting Low Sump T
Evap Pump Off
Waiting For Load
Cond Pump Off
Cond Pump On
MCR Started
MCR Off: Rapid Shtdn
MCR Off: Routn Shtdn
Evap Pump Off
Running: Hi Disch T
Running: Lo Evap T
Running: Soft Load
Running: Max Pulldn
Running: Rem Amp Lim
Running: Man Amp Lim
Running: Net Amp Lim
Running: Manual Load
Running: Max Amp Lim
Running: Min Amp Lim
Load Recycle
Pre-Lube
Start Unload
Post-Lube
Evap Pump on-Recirc
Oil Pump On-Prelube
Startup Unloading
Running OK:
Shutdown Unloading
Running: Spt 44.0°F 1
Post Lube
Chiller Operating Mode
1
Motor Amps=xx%RLA 2 1-100% Motor Current
Ent Evap=xx.x°F 1 Entering Evap Water Temp
2Ent Cond=xx.x°F 2 Entering Cond Water Temp
Lvg Evap=xx.x°F 1 Leaving Evap Water Temp
1
3Lvg Cond=xx.x°F 2 Leaving Cond Water Temp
Press the "NEXT MENU" key and Menu 2 (Water Temps/Flow) will be displayed. This menu has two
screens. Screen 1, line 1, field 1 indicates the entering evaporator water temperature and line 1, field 2
indicates entering condenser water temperature. Line 2, field 1 indicates the leaving evaporator water

OM 200MICRO 19
temperature and line 2, field 2 indicates the leaving condenser water temperature. Line 3, field 1
indicates the evaporator delta temperature. This is the difference between the entering and leaving
water temperature and indicates the 'load' on the chiller and the performance of the chiller. Line 3, field
2 indicates the condenser delta temperature. The design delta temperature of the evaporator and
condenser should be recorded. Any large changes in the delta temperatures is an indication of
potential problems that could be associated with fouled condenser or evaporator tubes.
Press the "NEXT ITEM" key and screen 2 will display additional information. Line 1, field 1 will
indicate the entering heat recovery temperature. (This is an optional operating parameter and it will
display a value only if the optional heat recovery sensors are installed.) Line 1, field 2 will indicate
the flow rate through the evaporator in gallons per minute (gpm). (This is an option and the optional
flow meter must be installed in the piping system.) Line 2, field 1 indicates the leaving heat recovery
water temperature (optional). Line 2, field 2 indicates the condenser water flow in gallons per minute
(optional). Line 3, filed 1 indicates the delta temperature of the heat recovery system (optional). The
delta temperature of the heat recovery system multiplied by the water flow rate and a special factor
would provide the amount of heat recovered in Btu's. This information could be compared to design
conditions to determine system operation. Pressing the switch key will toggle between this menu and
Menu 12 (Leaving Evap Set Points). This allows the operator to compare actual operating conditions
versus set points.
Menu 2, Water Temperatures
Item
Screen Line Display Field Range Extended Name
Ent Evap=xx.x°F 1 Entering Evap Water Temp
1Ent Cond=xx.x°F 2 Entering Cond Water Temp
Lvg Evap=xx.x°F 1 Leaving Evap Water Temp
2Lvg Cond=xx.x°F 2 Leaving Cond Water Temp
Delta T=xx.x°F 1 Evap Water Delta Temp
1
3Delta T=xx.x°F 2 Cond Water Delta Temp
Ent Ht Rcvy=xx.x°F 1 Heat Recvy Ent Water Temp
1Evap Flow=xxxxgpm 2 Averaged Evap Water Flow
Lvg Ht Rcvy=xx.x°F 1 Heat Recv Lvg Water Temp
2Cond Flow=xxxxgpm 2 Averaged Cond Water Flow
2
3 Delta T=xx.x°F 1 Heat Rcvy Delta Temp
Press the "NEXT MENU" key and Menu 3 (Refrig Temps/Press) will be displayed. This menu has
three screens. The refrigerant temperatures and pressures allows the operator to determine if the
chiller is performing properly. These values should be recorded in a chiller log on a daily basis. The
values will change as the load, condenser temperature and evaporator temperature vary. The operator
should be able to correlate displayed information to varying load conditions.
Screen 1, line 1, field 1 indicates the saturated evaporator refrigerant pressure and temperature. The
evaporator pressure is measured using a pressure transducer and the associated temperature is
calculated using refrigerant tables stored in the computer memory. Line 2, field 1 indicates the
saturated condenser refrigerant pressure and temperature. The condenser pressure is measured using
a pressure transducer and the associated temperature is calculated. Line 3, field 1 indicates the
suction line temperature. This is measured with a thermister in the inlet suction pipe before the inlet
guide vanes at the compressor. Line 3, field 2 indicates the liquid line temperature and is measured
with a thermister in the liquid line leaving the condenser.
Press the "NEXT ITEM" key and screen two will display additional information. Screen 2, line 1, field
1 indicates the suction superheat. This value is determined by subtracting the saturated evaporator
temperature from the suction line temperature. Line 1, field 2 indicates the amount of subcooling of
the liquid refrigerant. This temperature is calculated by subtracting the liquid line temperature from
the condenser temperature. Line 2, field 1 indicates the refrigerant temperature after it leaves the
compressor and before entering the condenser. Line 2, field 2 indicates the condenser approach
temperature. This temperature is calculated by subtracting the leaving condenser water temperature
from the saturated condenser refrigerant temperature. Line 3, field 1 indicates the discharge refrigerant
superheat. This temperature is calculated by subtracting the refrigerant saturated condenser
temperature from the refrigerant discharge temperature. Line 3, field 2 indicates the evaporator

20 OM 200MICRO
approach temperature. This temperature is calculated by subtracting the evaporator refrigerant
temperature from the evaporator leaving water temperature.
Press the "NEXT ITEM" key and screen 3 will display additional information. Line 1, field 1 indicates
the compressor lift pressure. This value is calculated by subtracting the evaporator pressure from the
condenser pressure. This indicates the work by the compressor.
Menu 3, Refrigerant Temps/Press
Item
Screen Line Display Field Range Extended Name
1 Saturated Evap=xx.x°F/xx.xpsi 1 Saturated Refg Evap Temp/Press
2 Saturated Cond=xx.x°F/xx.xpsi 1 Saturated Refg Cond
Temp/Press
Suct Line=xx.x°F 1 Suction Line Refg Temp
1
3Liquid Line=xx.x°F 2 Liquid Line Refg Temp
Suct Suprht=xx.x°F 1 Suction Superheat
1SubCool=xx.x°F 2 Liquid SubCooling
Discharge=xx.x°F 1 Discharge Temp
2Cond Apprch=xx.x°F 2 Condenser Approach Temp
Dsch Suprht=xx.x°F 1 Discharge Superheat
2
3Evap Apprch=xx.x°F 2 Evap Approach Temp
1 Lift Press=xx.xpsi 1 System Lift Pressure
32 Lift Temp=xx.xF 1 System Lift Temperature
Press the "NEXT MENU" key and Menu 4 (Motor Amps) will be displayed. Menu four has one
screen. Line 1, field 1 indicates the percent rated load amps. This value is calculated by comparing
measured run amps with a full load amp value entered by the start-up technician. Line 2, field 1
indicates the actual motor amps as measured by a current transformer on one leg of the compressor
wiring. Line 3, field 1 indicates the amp limiting value if limiting is being enforced by the control
software. Pressing the switch key will toggle between this menu and Menu 13 (MotorAmp Set
Points). This allows the operator to compare actual operating conditions versus set points.
Menu 4, Motor Amps
Item
Screen Line Display Field Range Extended Name
1 % Rated Ld amps=xx.x% 1 Percent Rated Load Amps
2 Motor Amps=xxxx 1 Actual Motor Amps1
3 Limit=xxx 1 Effective Amp Limiting
Press the "NEXT MENU" key and Menu 5 (Oil Temperatures) will be displayed. Menu five has one
screen. Line 1, field 1 indicates the oil vent pressure as measured with a pressure transducer in the oil
sump housing. Line 1, field 2 indicates the oil temperature in the oil sump as measured with a
thermister located in the oil sump housing. Line 2, field 1 indicates the oil feed pressure as measured
by a pressure transducer in the oil line of the oil pump discharge. Line 2, field 2 indicates the
temperature of the oil as measured by a thermister in the oil line after the oil cooler. This is the
temperature of the oil that is supplied to the compressor for lubrication. Line 3, field 1 indicates the
net oil pressure as calculated by subtracting the evaporator pressure from the oil feed pressure. This
indicates the actual oil pump pressure. Pressing the switch key will toggle between this menu and
Menu 21 (Oil Set Points). This allows the operator to compare actual operating conditions versus set
points.
Menu 5, Oil Temperature
Item
Screen Line Display Field Range Extended Name
Vent Press=xx.xpsi 1 Oil Vent Pressure
1Sump Temp=xx.x°F 2 Oil Sump Temp
Feed Press=xx.xpsi 1 Oil Feed Pressure
2Feed Temp=xx.x°F 2 Oil Feed Temp
1
3 Net Press=xx.xpsi 1 Oil System Net Pressure