Compu-aire SYSTEM 2500 S User manual

Rev.01 03-27-17
Page 1 of 67
Compu-Aire
SYSTEM 2500 S
PROGRAMMABLE CONTROLLER
-USER MANUAL-
8167 Byron Road Whittier, CA 90606
Phone: [phone] Fax: [phone]

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Compu-Aire
SUBJECT TO CHANGE WITHOUT INCURRING OBLIGATION
Table of Contents
1.0 INTRODUCTION.....................................................................................................................................8
2.0 QUICK REFERENCE GUIDE.....................................................................................................................9
3.0 SEQUENCE OF OPERATIONS ...............................................................................................................11
3.1 Standard Units in General...........................................................................................................11
3.2 How to Turn the Unit ON............................................................................................................11
3.3 Lead/Lag Redundancy –cLAN Network......................................................................................11
3.4 Air Cooled DX with Chilled Water Plus........................................................................................12
3.5 Air Side Economizer ....................................................................................................................13
3.6 Water Side Economizer Energy miser (EM) Unit Using 2-Way Valves........................................13
3.7 Water Cooled Energy Miser........................................................................................................15
3.8 Dry Fluid Cooler with Energymizer .............................................................................................16
3.9 Special Pump and Dry Fluid Cooler control logic........................................................................18
3.10 Optional features........................................................................................................................19
4.0 CONFIGURATION.................................................................................................................................19
4.1 Software version.........................................................................................................................19
5.0 TECHNICAL SPECIFICATIONS ...............................................................................................................20
5.1 Controller and Display.................................................................................................................20
5.2 General Characteristics...............................................................................................................20
5.3 Mechanical Characteristics .........................................................................................................21
5.4 Electrical Characteristics.............................................................................................................21
5.5 Digital Inputs...............................................................................................................................22
5.6 Universal inputs ..........................................................................................................................23
5.7 Analog Outputs ...........................................................................................................................24
5.8 Digital Outputs............................................................................................................................24
5.9 Cable Length ...............................................................................................................................24
5.10 Standard Input / Outputs............................................................................................................25
5.11 Optional Features .......................................................................................................................26

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5.12 Functional characteristics ...........................................................................................................26
5.13 Building Management System ....................................................................................................26
6.0 CONTROLLER INTERFACE ....................................................................................................................27
6.1 Navigation Buttons .....................................................................................................................27
7.0 Navigation Menu.................................................................................................................................27
7.1 Menu Tree...................................................................................................................................28
7.2 Accessing Submenus...................................................................................................................29
7.3 Main Menu Selection..................................................................................................................29
7.4 Unit Status...................................................................................................................................29
7.5 Alarms .........................................................................................................................................31
7.5.1 Alarm Viewing and Function...............................................................................................31
7.5.2 Alarm Reset.........................................................................................................................31
8.0 SETUP MENU.......................................................................................................................................32
8.1 Setpoints .....................................................................................................................................33
8.1.1 Changing Setpoints .............................................................................................................33
8.1.2 Changing Alarm Setpoints...................................................................................................34
8.2 Clock Setup..................................................................................................................................36
8.2.1 Time and Date Setup...........................................................................................................36
8.2.2 Night Setback ......................................................................................................................36
9.0 RUN TIME HOUR METERS...................................................................................................................36
10.0 BUILDING MANAGEMENT SYSTEM (BMS) ..........................................................................................38
10.1 Modbus .......................................................................................................................................38
10.1.1 Mounting.............................................................................................................................38
10.2 LONWORKS .................................................................................................................................40
10.2.1 General characteristics .......................................................................................................40
10.2.2 Physical channels ................................................................................................................40
10.2.3 Physical Circuit Board Layout..............................................................................................40
10.2.4 LED Color Description .........................................................................................................41
10.2.5 Installation ..........................................................................................................................41
10.2.6 Connection to the CONTROLLER Controller........................................................................42
10.2.7 Connection to the LonWorks® network..............................................................................42

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10.2.8 Service pin...........................................................................................................................42
10.2.9 WINK event .........................................................................................................................43
10.3 BACNET OVER TCP/IP..................................................................................................................44
10.3.1 Installation ..........................................................................................................................44
10.3.2 Functions.............................................................................................................................44
10.3.3 Default parameters.............................................................................................................44
10.3.4 Restarting the software ......................................................................................................45
10.3.5 Configuration ......................................................................................................................45
10.3.6 Web server..........................................................................................................................47
10.3.7 Accessing the operating system by authentication ............................................................47
10.3.8 CGI script.............................................................................................................................48
10.3.9 SNMP...................................................................................................................................48
10.3.10 BACnet.............................................................................................................................48
10.3.11 WARNINGS......................................................................................................................48
10.4 BANET over MS/TP......................................................................................................................49
10.4.1 Installation ..........................................................................................................................49
10.4.2 Meaning of the jumpers......................................................................................................50
10.4.3 Operation............................................................................................................................50
10.4.4 Recalling the factory configuration (“factory bootswitch” mode) .....................................52
10.4.5 Configuration ......................................................................................................................52
10.4.6 BACNET Parameter Description..........................................................................................53
11.0 TECHNICIAN MENU.............................................................................................................................54
11.1 Alarm Setup.................................................................................................................................54
11.1.1 Available Alarms..................................................................................................................56
11.1.2 Sensor Offset.......................................................................................................................57
11.2 Network Setup ............................................................................................................................57
11.3 Manual Control ...........................................................................................................................58
12.0 FACTORY SETTING...............................................................................................................................59
12.1 Factory Setting Menu Tree .........................................................................................................59
12.1.1 Digital Inputs and Digital Outputs.......................................................................................60
12.1.2 Analog Inputs and Analog Outputs .....................................................................................61

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12.1.3 Changing Passwords............................................................................................................62
12.2 Factory Reset ..............................................................................................................................62
13.0 TROUBLESHOOTING GUIDE ................................................................................................................63

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Table of Figures
Figure 1 User Interface..................................................................................................................................9
Figure 2 about Screen.................................................................................................................................19
Figure 3 External display.............................................................................................................................20
Figure 4 System 2500 controller.................................................................................................................20
Figure 5 power connection.........................................................................................................................21
Figure 6 Digital inputs .................................................................................................................................22
Figure 7 Analog outputs..............................................................................................................................24
Figure 8 –Status screen..............................................................................................................................27
Figure 9 Menu tree .....................................................................................................................................28
Figure 10 - Alarms Message........................................................................................................................31
Figure 11 password prompt........................................................................................................................32
Figure 12 default passwords.......................................................................................................................32
Figure 13 temperature setpoint..................................................................................................................33
Figure 14 Discharge setpoint ......................................................................................................................33
Figure 15 Humidity setpoint .......................................................................................................................34
Figure 16 Economizer setpoint ...................................................................................................................34
Figure 17 Temperature alarm setpoints .....................................................................................................34
Figure 18 Humidity alarm setpoints............................................................................................................35
Figure 19 Discharge alarm setpoints...........................................................................................................35
Figure 20 Shutdown alarms ........................................................................................................................35
Figure 21 Transducers alarm setpoints.......................................................................................................35
Figure 22 Date and time..............................................................................................................................36
Figure 23 equipment run hours ..................................................................................................................37
Figure 24 - Building management system...................................................................................................38
Figure 25 - Communication protocol..........................................................................................................38
Figure 26 - LONTalk Card ............................................................................................................................40
Figure 27 - Remove plastic cover................................................................................................................42
Figure 28- Cut out window .........................................................................................................................42
Figure 29 - Installing plugin card.................................................................................................................42
Figure 30 - Replacing windows cover..........................................................................................................42
Figure 31 - PCOWeb....................................................................................................................................46
Figure 32 - Window cover...........................................................................................................................46
Figure 33 - Installing PCOWeb ....................................................................................................................46
Figure 34 - Installing plastic cover...............................................................................................................46
Figure 35 - Alarm setup...............................................................................................................................54
Figure 36 - Alarm Setup ..............................................................................................................................54
Figure 37 –IP address.................................................................................................................................57
Figure 38 - Network configuration..............................................................................................................57
Figure 39 - Factory Setting..........................................................................................................................59

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Figure 40. Digital inputs ..............................................................................................................................60
Figure 41. Digital outputs............................................................................................................................60
Figure 42. Analog inputs .............................................................................................................................61
Figure 43. Analog outputs...........................................................................................................................61
Figure 44. Password management..............................................................................................................62
Figure 45. Factory reset ..............................................................................................................................62

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1.0 INTRODUCTION
The System 2500S is a programmable controller based on a double microprocessor, designed for
precise "Smart" control of an air conditioning system. The System 2500S is made up of a
microprocessor based MAIN BOARD equipped with a set of terminals used to interface the
microcontroller board to the controlled devices; such compressors, fans, heaters, humidifiers,
and valves. The program is retained in a flash based memory and configuration parameters are
permanently stored (even in the case of a power failure) in a non-volatile memory.
The System 2500S also includes a microprocessor based TERMINAL unit complete with graphical
touch screen display with built in navigation keypad and led indicators allowing the users to
easily set the controlled parameters for set points, dead bands, alarm thresholds, and carry out
the main working operations (on/off, displaying controlled variables, printouts). The controller
and graphical display terminal are powered by 24VAC power supply using low voltage control
transformers from the unit. Connection between the terminal unit and main board is necessary
only when programming the System 2500S basic parameters. The controller is linked to a
graphic display terminal via standard three wire cable.
The System 2500S represents the evolution of the microcontroller towards the unpresented
networking capabilities with integrated Ethernet interfaces offer a wide range of open stand
protocols for local connectives. The new operating system is optimized to ensure optimal
system resource usage and increase speed and reliability.

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2.0 QUICK REFERENCE GUIDE
The controller is fully programmed and pre-configured per system configuration. Further
tweaking may be required to better fit the application.
Figure 1 User Interface
Active alarm / Reset alarm
Increment/Toggle
variables/Up button
Main menu
Enter selection /
Move cursor to next
Previous screen/menu
Decrease/Toggle
variables/Down
button
Table 1 Button layout

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Fan active
Humidifier active
Cooling active
Dehumidification
Heating active
Air econ active
Heat-pump active
Table 2 Mode of operation icons
1Shows current time and date. Time is showed in military format.
2Shows current room temperature and relative humidity
3Shows current cooling demand
4Shows current heating demand
5System status
6Mode of operation. See Table 2.
7Quick Menu: Use Up/Down buttons to toggle option
On/Off menu
Setpoint menu
System status
Table 3 Blink Menu Options
1
2
3
4
5
6
7

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3.0 SEQUENCE OF OPERATIONS
3.1 Standard Units in General
In general, the controller is operated as follows. Note that the followings are applicable while the
controller is in active mode and only apply to DX and Chilled Water units.
•Fan starts up on demand for cooling, heating, humidifying or dehumidifying, or operates
continuously
•Sequences the compressors on in stages with adjustable delays to meet demand for
specified temperature and humidity setpoints.
•Sequences the heaters on in stages with programmable delays to meet demand for heating
or reheat during dehumidification mode
•Activates the humidifier as needed to meet the humidity demand
•Dehumidification is achieved by means of cooling to reduce the humidity level. During the
dehumidification process, if the temperature falls below the room set point, heating is
brought on to reheat the air and maintain room temperature.
•The controller monitors the complete system for any sensors, fans, compressors, heaters
and humidifier failure. Upon critical failures, the complete system will shut down with
alarm. For certain component failures, the applicable feature is disabled to insure safe
operation. For example, when compressor failure occurs, the failed compressor shall be
locked out but the system shall provide cooling by other compressor if available. On a
heater failure, the heaters are locked out. The system will not use that function until
manually reset on the display. The controller also keeps the history of last 100 alarms after
you reset them.
3.2 How to Turn the Unit ON
•From the status screen, navigate to the On/Off menu and press enter. Use the Up/Down
arrow buttons to toggle the On/Off operation.
•The System Status screen should indicate the current system operating mode
•Default time delay for evaporator fan is 30 seconds to avoid short cycling
•Unit will automatically control the necessary mode of operation to maintain room setpoints
3.3 Lead/Lag Redundancy –cLAN Network
System 2500+ series controllers can be set for n+1 redundancy setup. A maximum of 32 units can
be linked together on the cLAN network. The cLAN networked systems are identified with IP
address numbers. Any system within the network can be configured as master unit. This
alleviates the need to cumbersome wiring with the use of stand card Ethernet cables. In case of
master unit is out of service, any of the slave unit can be set as a new master from a few its own
interface. No wiring changes are needed. Each controller is self-dependent with necessary
sensors and it can be used as a stand-alone unit. When used on the cLAN Network, each unit are
not required to have to have the same software revision and date.

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When the Master goes offline, all standby systems become active to as standalone mode. This
reduces the chance of the controlled space temperature and humidity trails off setpoints. When
an active master or slave units goes into alarm, next standby system or all standby systems should
become active while the system in alarm is turned off. Network alarm events are programmable
via the technician menu. Communication between systems is maintained by a synced heartbeat.
The units can be set to cycle to achieve equal run time on each unit. At the end of each cycle, the
role of each unit switches to its counterpart, meaning the Master becomes the Slave and the
Slave becomes the Master during the next cycle. During each cycle, the units operate according
to the above lead/lag logic.
3.4 Air Cooled DX with Chilled Water Plus
Summary of Equipment
The primary system shall be Chilled Water Cooling. Direct Expansion Cooling shall be setup as a
back up to the Chilled Water system. Both systems are designed to work independent of each
other.
The Chilled Water System comes standard with a three (3) way water modulating valve, coil, and
an optional “no water flow switch”. The DX system is equipped with a DX coil, compressor(s), and
outdoor air cooled condenser. Optional heaters and humidifiers are also available if needed.
A unique feature of Air Cooled/Chilled Water Plus units is that the chilled water coil is located at
the side of the direct expansion coil. The auxiliary chilled water coil is custom sized so that it
provides identical cooling capacity obtained during the refrigeration cycle with the compressor
operating.
Cooling-Chilled Water
Chilled Water cooling is the primary cooling system for C+ units. For optimum performance, the
controller is programmed to call chilled water cooling for the first 300 seconds regardless of the
chilled water temperature.
The C+ unit can switch over from one cooling mode to another based on sensing Chilled Water
flow or Chilled Water temperature. The standard practice is to sense the Chilled Water flow for
switching.
If “No Water flow”switch is selected, the unit senses the flow of chilled water by using a pressure
differential switch and switches over to DX cooling based on loss of water flow. When no water
flow switch is selected for switch over, the unit will only work on either DX or C.W. cooling mode.
If chilled water supply temperature is selected for switch over, than the unit shall continue with
chilled water cooling if the chilled water supply temperature is below the required temperature
set point and switch over to the DX cooling.

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Cooling-Direct Expansion
Direct Expansion Cooling is designed to operate when the water flow switch senses that there is
no water flow. A digital signal is sent to the system from the controller to modulate the three (3)
way valve to cut water flow to the chilled water coil and the backup system direct expansion
cooling should start. The controller signals the compressor to start cooling. The outdoor
condenser gets energized as needed.
3.5 Air Side Economizer
Summary of Equipment
The Economizer Mixing Box is factory provided; however, it might be installed in the field by
others. Typically, the Air Side Economizer Mixing Box is provided for our Maxi-Kool unit with
System 2200 series controller.
Sequence of Operation
The evaporator fan and a set of dampers for the economizers are energized depending on heating
or cooling demands. The CONTROLLER controller commands the economizer box to bring either
the minimum amount of outside air or only outside air based on outside air temperature and
humidity. The controller determines whether the outdoor air temperature and humidity is
suitable for “economizer-cooling”. If the outdoor air is suitable, mechanical cooling shall be
locked out by the outdoor enthalpy control. The set of economizer damper actuators shall be
energized, operating the outdoor air and the return air dampers. The economizer damper
actuators shall be regulated to maintain proper discharge air temperature. When outdoor air is
not suitable for “economizer-cooling”, the Economizer shall be locked out and the outdoor air
damper shall maintain minimum position while the indoor fan is operating. Upon unit shutting
down or power loss, the spring return motor actuator shall close the outdoor air damper. The
Economizer shall be automatically locked out during the heat mode (if applicable).
The Air Side Economizer box shall include: prewired modulating spring return damper actuators,
economizer control logic with compressor assist option, minimum outside air damper position
control, economizer control sensors including outdoor air temperature and humidity (enthalpy)
sensor, supply air and/or mixed air sensors. The supply air temperature sensor is used to maintain
the desire supply air temperature using DX and Economizer cooling together. The exhaust of
room air during economizer cooling mode shall be done by others in the field.
3.6 Water Side Economizer Energy miser (EM) Unit Using 2-Way Valves
Summary of Equipment
Energy miser units are provided with Dual Cooling options. DX cooling using Compressor based
system and Economizer cooling using Water Side Economizer Coil.
The primary system shall be Direct Expansion Cooling. The free cooling Energy miser coil is
provided together with the DX cooling coil. If the Water temperature drops below the Energy

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miser set point, the condenser water is diverted to the free cooling coil and DX cooling will be
programmed to either turned off or made available to assist based on demand.
The Energy miser System shall be provided with a Two (2) way water regulating valve for
condenser coil, a Two (2) way modulating chilled water valve for energy miser coil, DX coil(s),
compressor(s) and co-axial water condenser(s). The water valves on water cooled condensers and
free cooling energy miser CW Valves will allow the water flow in either condenser coil or free
cooling EM coil. The two way control valve shall control the amount of flow to auxiliary energy
miser cooling coils to meet the demand when in EM cooling mode. The Two way water regulating
valve will control the amount of water flow in condenser based on the refrigerant pressure in DX
cooling mode. System shall be programmed to do either DX cooling or EM cooling based on
entering water temperature.
Energy miser systems are connected to Cooling Tower or Dry Fluid Coolers to obtain re-circulating
water or water glycol solution. In addition, the system is equipped with steam generating
humidifier, electric reheat and microprocessor based controller.
A unique feature of Energy miser system is that the free cooling water coil is located just before
the direct expansion coil and is properly sized to provide the same cooling capacity as the DX
system at 45 Deg. F entering water temperature. The indoor unit will send a signal to enable and
disable the outdoor auxiliary equipment. The outdoor equipment has its own control logic to
provide water temperature suitable for either EM mode or DX cooling mode.
Cooling-Direct Expansion
Direct Expansion Cooling shall operate when the water temperature increases above the specified
EM set point. A digital signal is sent to the system by microprocessor to signal the compressors
and the two (2) way valves will regulate the water flow into the water cooled condensers based
on the refrigerant pressure. Each compressor system shall have separate 2-Way water regulating
valves. The Energy miser mode depends on the entering water temperature and it is adjustable.
Cooling-Energy miser Mode
The unit can switch over from DX cooling mode to Free cooling Energy miser mode based on the
Entering Water temperature.
Unit shall start in DX cooling mode. If the temperature of water supply drops below the set point
for the Energy miser mode, the unit will switch over to the Energy miser free cooling mode. The
outdoor fluid cooler shall be provided with energy miser control panel to maintain lower fluid
temperature during energy miser mode.
In the free cooling energy miser mode the compressors will remain shut off while the fans of the
unit shall be on. Humidification and Dehumidification modes shall be operating as needed.

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3.7 Water Cooled Energy Miser
Summary of Equipment
Energy miser units are provided with Dual Cooling options. DX cooling using Compressor based
system and Economizer cooling using Water Side Economizer Coil.
The primary system shall be Direct Expansion Cooling. The free cooling Energy miser coil is
provided together with the DX cooling coil. If the Water temperature drops below the Energy
miser set point, the condenser water is diverted to the free cooling coil and DX cooling will be
programmed to either turned off or made available to assist based on demand.
The Energy miser System shall come standard with a three (3) way water regulating valve for
condenser coil, a three (3) way modulating chilled water valve for energy miser coil, DX coil(s),
compressor(s) and co-axial water condenser(s). The water valves on water cooled condensers and
free cooling energy miser CW Valves are Three Way mixing type designed to divert the flow in
either condenser coil or free cooling EM coil. Three (3) way is used to maintain pressure drop, as
constant GPM is required for free cooling systems. The (3) three way control valve shall control
the amount of flow to auxiliary energy miser cooling coils and maintain constant temperature and
relative humidity
Energy miser systems are connected to Cooling Tower or Dry Fluid Coolers to obtain re-circulating
water or water glycol solution. In addition, the system is equipped with steam generating
humidifier, electric reheat and microprocessor based controller.
A unique feature of Energy miser system is that the free cooling water coil is located just before
the direct expansion coil and is properly sized to provide the same cooling capacity as the DX
system at 45°F entering water temperature.
Cooling-Direct Expansion
Direct Expansion Cooling shall operate when the water temperature increases above the specified
set point. A digital signal is sent to the system by microprocessor to signal the three (3) way valve
to divert the water flow from the free cooling coil to the water cooled condensers and the direct
expansion cooling mode shall start. The microprocessor shall signal the compressor to start
cooling and at the same time energize the water regulating valve to supply water flow to the co-
axial condenser. The Energy miser mode depends on the entering water temperature and it is
adjustable.
Note: Continuous water shall be flowing through the chilled water valve and will only supply
water to coil when called upon.

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Cooling-Energy miser Mode
The unit can switch over from DX cooling mode to free cooling energy miser mode based on the
Entering Water temperature.
Unit shall start in DX cooling mode. If the temperature of water supply drops below the set point
for the Energy miser mode, the unit will switch over to the Energy miser free cooling mode. The
controller will send signal to the auxiliary equipment to run Energy miser mode for fluid
temperature control. The outdoor fluid cooler shall be provided with energy miser control panel
to maintain lower fluid temperature during energy miser mode.
In the free cooling energy miser mode the compressors may shut off while the fans of the unit
shall be on. Humidification and Dehumidification modes shall be operating as needed. The
Compressors can be locked to remain off during energy miser mode if necessary.
3.8 Dry Fluid Cooler with Energymizer
Summary of Equipment
DRY FLUID COOLER (DFC): The Dry Fluid Cooler Shall Consist of Casing, Coil, Direct-drive Propeller
Fan(s) driven by individual Fan Motor(s), Fan Guard and Mounting Legs. All fan motors shall be
factory wired to a common electrical control box. The Dry Fluid Cooler shall be arranged for
Vertical Air Flow.
The Glycol Coil shall have aluminum fins bonded to copper tubes and shall have full collars that
completely cover the copper tubes. The coil shall be pressure tested to 350 psig and shall be
designed for counter flow for high heat transfer efficiency.
The Dry Fluid Cooler casing shall be made from a non-corrosive metal to minimize maintenance.
Adjustable mounting legs and supports shall be furnished with the DFC. Vibration isolators of the
rubber and shear or spring type are to be field provided by others.
The motors shall be permanently lubricated, sealed ball bearings, with inherent overload
protection. Motors shall be mounted inside the Dry Fluid Cooler Casing for weather protection.
The direct drive fan blades shall be aluminum, and shall be protected by a heavy gauge, steel
wire, zinc plated, and epoxy coated fan guard. Full width baffles to prevent bypass air shall
separate each fan section.
Dry Fluid Cooler (DFC) requires separate power supply and one set of dry contact from indoor unit
to Enable/Disable.
DFC is equipped with its own control panel that includes power block, fan contactors, aqua stats,
freeze stats, relays and single or dual pump package control as necessary.
Aqua stats are installed in the control panel and bulbs to be attached with leaving water header of
the coil.
For understanding purpose use 4 fan dry fluid cooler with drawing # 700-232-041

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The fluid cooler shall be provided with ambient T-stats to control the water temperature during
DX cooling mode. The fluid cooler shall bypass the T-Stat control logic and run all fans
continuously during Energy Miser mode.
Condenser cooling mode
If the water temperature is above 50Deg. F. (Default setting) the DFC will be in normal condenser
cooling mode. Aqua stat # 1 will be open above 50 Deg. F.
In normal cooling mode, DFC will be enabled by either of the compressor from indoor unit. The
Freeze stat is installed in series of the enabling signal. If the freeze stat opens, the DFC unit will be
fully disabled.
1. The first fan of DFC runs continuously as long as enabling signal is present.
2. The default setting for second fan to cycle OFF is 60 Deg. F and below with aqua
stat
3. The default setting for third fan to cycle OFF is 70 Deg. F. and below with aqua
stat #
4. The default setting for forth fan to cycle OFF is 75 Deg. F. and below with aqua
stat #
5. All these default settings are field adjustable to fine tune the unit operation.
Energy miser cooling mode
During winter months, when water temperature drops below the 50Deg. F. the aqua stat # 1 will
close and DFC unit will switch over to free cooling energy miser mode. In Energy miser mode, all
other aqua stat (aqua stat 2, 3 and 4) will be bypassed and all fans will run continuously. The free
cooling temperature set point on Aqua stat # 1 must synchronize with Energy miser water
temperature set point for indoor unit.
Pumps
Summary of Equipment
PUMP PACKAGE: The pump package shall include a close coupled, industrial duty pump with
heavy-duty ball bearings motors, stainless steel shafts and bronze fitted construction. The pump
package shall include pump starter, aqua-stats, and fan cycling contactor(s) to control the
condenser glycol temperature. The control panel shall be factory provided for filed installation in
a weatherproof box provided on the Dry Fluid Cooler. The pump shall be protected with a base
and weather shield from the ambient conditions.
DUAL PUMP PACKAGE (Optional): The dual pump package shall include close-coupled, industrial
duty pumps with heavy-duty ball bearings motors, stainless steel shafts and bronze fitted
construction. The pump package shall include pump starters, aqua-stats, and fan cycling
contactor(s) to control the condenser glycol temperature. The control panel shall be factory
provided for filed installation in a weatherproof box provided on the Dry Fluid Cooler. The pumps
shall be protected with a base and complete vented weather enclosure from the ambient

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conditions. The optional Pressure Differential (No Water Flow) switch shall be provided for field
installation.
GLYCOL PUMP: A matching centrifugal circulating pump is provided for field mounting and piping.
Pump Operation
When compressor is on the pump and fluid cooler will be enabled. Note that this is in DX cooling.
In free cooling the logic is the same, as pumps is enabled with economizer cooling.
3.9 Special Pump and Dry Fluid Cooler control logic
Pump speed adjusted based on differential pressure across pumps as 2-way control valves modulate.
Dry cooler and Pump controller Sequence of operation
Free cooling mode
Either outdoor air temperature is monitored or a signal from each crac unit (free cooling and DX
condenser) is sent to the pump controller to determine which function is provided.
Fan speed may be increased sufficiently to allow pump minimum operating speed to be maintained
should zone loads decrease, thus decreasing flow below safe pump operation.
Outside air temperature reaches 48F
Pump controls switch to free cooling mode –Fans run 100% until condenser outlet temperature reaches
38F, at which time fans speed will reduce to maintain 38F or minimum pumps speed is reached, then
fans will reduce speed to maintain minimum pump speed, which is accomplished by 2-way valves
modulating open is response to increased condenser water supply temperature.
Controls shall monitor both fan KW and Pump KW energy consumption and determine best speed
combination to maintain lowest condenser supply water temperature during free cooling more.
DX Cooling mode
Outside air temperature 50F
Pump control increases fan speed as condenser water temperature increases. Maintain 65F condenser
outlet water by modulating fan speed. At 75F exiting condenser water temperature fan speed is 100%.
Controls shall monitor both fan KW and Pump KW energy consumption and determine best speed
combination to maintain lowest condenser supply water temperature during DX cooling more.

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3.10 Optional features
•Discharge air temperature sensor to prevent overheating or cooling of the air stream
•Outside air temperature sensor for automatic temperature adjustment or economizer
action
•Free-cooling temperature sensor for water cooled systems
•Hot gas bypass either by solenoid or by modulating electronic valve
•Redundant system operation of two or more units with automatic crossover and
compensation
•Networking to a central command computer, or to an existing building automation system
The System 2500S is truly one of the most powerful and flexible controllers available for HVAC
units today.
4.0 CONFIGURATION
The display unit is pre-configured at the factory for the most common user requirements.
Nonetheless, some settings can be changed to adapt the device specific needs.
4.1 Software version
Software version: During boot-up, the splash screen is shown briefly with a quick summary of the
loaded operation system along with software, boot, and O/S version. The about screen can also
be access via the menu. Version number is needed prior contacting the factory for technical
support.
Figure 2 about Screen

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Compu-Aire
5.0 TECHNICAL SPECIFICATIONS
5.1 Controller and Display
Figure 3 External display
Figure 4 System 2500 controller
5.2 General Characteristics
System 2500 is a microprocessor-based electronic controller developed in compliance with the
European RoHS standards. It provides a solution for many applications in the air-conditioning and
refrigeration sectors ensuring absolute versatility, allowing specific products to be created to
customer request. CONTROLLER runs the control program, and is fitted with the set of terminals
required for connection to the devices (compressors, fans…). The program and the parameters
are saved to FLASH-MEMORY and E2promfor safe keeping even in the event of power failures
(without requiring a backup battery). CONTROLLER also allows connection to the cLAN (Compu-
Aire Local Area Network) and can be connected, as well as to other System 2500S controllers. All
the controllers in the cLAN can exchange information (variables, digital or analogue, depending on
the application software used) at high transmission speed. Up to 32 units can be connected via