Baltimore Aircoil Company NEXUS Manual

OPERATION & MAINTENANCE MANUAL

DANGER: Rotating equipment will cause
severe personal injury or death to persons who
come in contact. Do not perform any service,
maintenance, or inspection on or near the
fan(s), motor(s), or inside the unit without first
ensuring that the fans and pump motors are
disconnected, locked out, and tagged out.
NOTE:
1. Recommended service intervals are the minimum for typical installations.
Different environmental conditions may dictate more frequent servicing.
2. Clean the conductivity sensor two weeks after initial start-up.
Recommended Maintenance Intervals[1]
Inspect and clean as necessary: Start-Up Monthly Quarterly Annually Shutdown
Inspect general condition of the unit and check unit for
unusual noise or vibration
Inspect and clean the fan guard
Inspect spray water basin and clean as required
Inspect and flush water distribution system as required
Check operation of solenoid make-up valve, mechanical
make-up valve, and drain valve
Check and adjust water level in the spray water basin
Check operation of pump(s)
Inspect and clean conductivity sensor{2}
Check basin heater and stand alone BAC heater control panel
(optional)
Drain spray water basin and connected piping
Inspect hCore™ Heat Transfer Technology
Inspect and clean strainers in piping (by others)
Inspect unit finish
Mechanical equipment system: Start-Up Monthly Quarterly Annually Shutdown
Check motor voltage and current
Check general condition of EC Fan System and clean motor
exterior when required
Check fan for rotation without obstruction
Check fan cycling for smooth operation

Table of Contents
Warnings and Cautions
2Safety Precautions
3Equipment Precautions
3General Maintenance Information
3Warranties
PART 1 Start-Up & Operation
6Start-Up
11 Operation
12 Spray Water Basin and Pump Water Control
13 Maintaining Water Quality
13 Fan Control
13 Cold Weather Operation
14 hCore™ Heat Transfer Technology Freeze Protection
16 Emergency f™ Heat Transfer Technology Drain
16 Spray Water Basin Protection
PART 2 Storage & Extended Shutdown
17 Prolonged Outdoor Storage
19 Extended Shutdown
PART 3 Detailed Component Maintenance Procedures
20 hCore™ Heat Transfer Technology
21 EC Fan System
22 DiamondClear™Design
26 iPilot™Control System
PART 4 Corrosion Protection
30 Water Treatment
31 Corrosion and Scale Control
32 Chemical Treatment Requirements
32 Passivation
32 Biological Control
33 Alternative Water Sources
33 Long Term Care of Stainless Steel
34 System Cleaning
PART 5 Bleed Rate
37 Example to Estimate Bleed Rate
PART 6 Operation Considerations for Accessories
38 Basin Heater and Stand Alone BAC Heater Control
Panel
40 Resonant Speed Identification Procedure
41 Positive Closure Dampers (PCDs)
PART 7 Troubleshooting Guide
42 Troubleshooting Guide
APPENDIX A iPilot™Control System
45 Menus
45 Software Menus
56 Controls Connections
OPERATION & MAINTENANCE »
NEXUS™MODULAR HYBRID COOLER
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WARNING
• WARNING: For basin and heater maintenance – switch off both of the control panels and lock and tag out the main disconnects.
• WARNING: The top horizontal surface of the unit is not intended to be used as a walking surface or working platform, and all
maintenance should be done in front of the equipment. If access to the top of the unit is desired, the purchaser/end-user is cautioned
to use appropriate means complying with applicable safety standards of governmental authorities.
• WARNING: Steps must be taken to avoid operation at or near system resonant frequency which could result in fan failure and possible
personal injury or damage. Refer to “Resonant Speed Identification Procedure” on page 40 for more details.
• WARNING: The recirculating water system may contain chemicals or biological contaminants, including Legionella, which could
be harmful if inhaled or ingested. Personnel exposed directly to the discharge airstream and the associated drift mists, generated
during operation of the water distribution system and/or fans, or mists produced by high pressure water jets or compressed air (if
used to clean components of the recirculating water system), must wear respiratory protection equipment approved for such use by
governmental occupational safety and health authorities.
• WARNING: Dangerous voltages are present in this equipment. To service the iPilot™Control System, disconnect the main electric power
supply to the control panel lock out and tag out the circuit. To service all other components on the unit, lock out and tag out the iPilot™
Control System. If ordered, the optional heater control panel should also be locked out and tagged out during service or maintenance.
• CAUTION: The operation, maintenance, and repair of this equipment shall be undertaken only by personnel authorized and qualified to
do so. All such personnel shall be thoroughly familiar with the equipment, the associated system and controls, and the procedures set
forth in this manual. Proper care, personal protective equipment, procedures, and tools must be used in handling, lifting, installing,
operating, maintaining, and repairing this equipment to prevent personal injury and/or property damage.
• CAUTION: Protect and secure this equipment and its premises against access by unauthorized personnel. Personal injury to members of
the public could result from interaction with the electrical and mechanical elements of this equipment.
• CAUTION: All electrical, mechanical, and rotating machinery are potential hazards, particularly for those not familiar with their design,
construction, and operation. Accordingly, use appropriate lockout procedures. Adequate safeguards (including the use of protective
enclosures where necessary) should be taken with this equipment both to safeguard the public from injury and to prevent damage to
the equipment, its associated system, and the premises.
• CAUTION: This equipment should never be operated without all access panels in place. For the protection of authorized service and
maintenance personnel, install a lockable disconnect switch located within sight of each equipment control panel.
• CAUTION: Steps must be taken to avoid operation at or near system resonant frequency which could result in fan failure and possible
personal injury or damage.
DANGER: Rotating equipment will cause severe personal injury or death to persons who come in contact. Do not perform any service,
maintenance, or inspection on or near the fan(s), motor(s), or inside the unit without first ensuring that the fans and pump motors are
disconnected, locked out, and tagged out.
DANGER
CAUTION
Safety Precautions

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• BAC units are typically installed immediately after shipment and many operate year round. However, if the unit is to be stored for a
prolonged period of time either before or after installation, certain precautions should be observed, as outlined in “Storage & extended
Shutdown” on page 17.
• Covering the unit with a clear plastic tarpaulin during storage can trap heat inside the unit and cause damage to the PVC components.
If units must be covered during storage, an opaque, reflective tarp should be used.
• Do not use steam or high pressure water to clean PVC eliminators, or materials other than steel.
• Do not use high pressure water exceeding 60 psi to clean the hCore™Heat Transfer Technology
• Do not use sharp or pointed objects, including screwdrivers and similar, for cleaning the hCore™Heat Transfer Technology.
• If noise or vibration persists, shut the unit down and correct the cause before continuing operation.
• Never use chloride or chlorine based solvents such as bleach or muriatic (hydrochloric) acid to clean stainless steel. It is important to
rinse the surface with warm water and wipe with a dry cloth after cleaning.
• The basin heater is not designed to prevent icing during unit operation.
General Maintenance Information
Equipment Precautions
NOTICE
The services required to maintain a piece of evaporative cooling equipment are primarily a function of the quality of the air and water in the
locality of the installation:
• AIR: The unit should be located such that unusual quantities of industrial smoke, chemical fumes, salt, or heavy dust do not enter the
equipment. Such airborne impurities entering into the equipment and absorbed by the recirculating water, which can form a corrosive
solution.
• WATER: As water evaporates from the equipment, dissolved solids are left behind, which were originally contained in the make-up water.
These dissolved solids may be either alkaline or acidic and as they are concentrated in the circulating water, they can cause scaling or
accelerated corrosion.
The extent of impurities in the air and water determines the frequency of most maintenance services and also governs the extent of water
treatment which can vary from a simple continuous bleed and biological control to a sophisticated treatment system. Refer to “Water
Treatment” on page 30 and “Biological Control” on page 32 for more details.
Warranties
Please refer to the Limitation of Warranties in the submittal package applicable to and in effect at the time of the sale/purchase of these
products. Described in this manual are the recommended services for start-up, operation, and shutdown, and the approximate frequency
of each.

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Figure 1. Nexus™ Modular Hybrid Cooler
NEXUS™ MODULAR HYBRID COOLER
Start-Up & Operation
1
1
2
3
11
12
20
21
4
5
6
7+8
9
10
14
17

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NEXUS™ MODULAR HYBRID COOLER
Start-Up & Operation
1. hCore™ Heat Transfer Technology: Exclusive closed loop heat transfer section with
stainless steel construction that offers high corrosion-resistance.
2. Fluid Connections: Fewest field piping connections due to innovative, easy-to-install
manifold with grooved connections.
3. iPilot™ Control System: Automatically controls equipment operation according to your
specific needs, including energy savings desired, water savings desired, and water
management.
4. EC Fan System: This Electronically Commutated (EC) Fan System includes a direct-
drive radial fan and a variable-speed EC motor.
5. Fan Guard: Protects operators and blocks large debris.
6. Hinged EC Fan System Access Panel: Allows for easy access to the EC Fan System.
7. Spray Water Basin: Small, workbench-height basin that collects recirculating spray
water.
8. Basin Access Cover: Allows easy access inside the spray water basin for inspection
and service.
9. Basin Interior Access Panels: Allows access to the water diverter and air baffle.
10. Spray Pump: Continuously circulates water through the system to meet cooling
demand. There is also an integral strainer to the spray pump which prevents large
debris from entering pump and spray distribution. Constructed of stainless steel for
corrosion-resistance.
11. Riser Pipe: Directs water to the spray distribution.
12. Water Distribution System: Evenly wets the hCore™ Heat Transfer Technology for
optimal thermal performance and reliability.
13. Water Diverter: Creates water turbulence in basin to minimize maintenance.
14. High and Low Level Switches (Not Shown): Sends water level signals for monitoring
and control.
15. Mechanical Make-up Valve (Not Shown): Provides fresh water to the unit to replenish
water that evaporates through the evaporative cooling process and is bled from the
sump.
16. Solenoid Make-up Valve (Not Shown): Normally closed valve controls when water is
sent to the basin during wet operation.
17. Drain Valve: This motorized valve is conductivity-controlled and is used to periodically
drain water to maintain water quality. It is also used to fully drain the basin to
minimize maintenance.
18. Conductivity Sensor (Not Shown): Sends signal that controls drain valve based on
water conductivity.
19. Outside Air Temperature Sensor (Not Shown): Sends signal that controls fan and
pump operation based on user inputs.
20. High Efficiency Drift Eliminators: Ensures that recirculating water remains in the unit
during operation.
21. Spray Distribution Access Panel: Allows for access to spray branches, nozzles, and
drift eliminators
Start-Up and Operation
Nexus™Modular Hybrid Cooler
DANGER: Rotating equipment
will cause severe personal injury
or death to persons who come in
contact. Do not perform any service,
maintenance, or inspection on or
near the fan(s), motor(s), or inside
the unit without first ensuring
that the fans and pump motors
are disconnected, locked out, and
tagged out.

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Start-Up
General
• If the unit will be in storage prior to start-up, follow the “Prolonged Outdoor Storage”
instructions on page 17.
• It is strongly recommended to install a removable 1/16” mesh strainer upstream of
the process fluid inlet to prevent large debris from entering the hCore™ Heat Transfer
Technology (closed loop heat transfer section).
• If the unit is mounted on vibration isolators (by others), refer to the vibration isolation
manufacturer’s guidelines before loading/unloading weight from the unit.
• Before opening the iPilot™ Control System panel, follow the proper lockout / tagout
procedures.
• It is recommended to install a strainer or filter in the make-up water supply line as
close as possible to the solenoid valve as possible to protect the valve from debris
buildup and diminished operation.
• Before starting the system the first time, flush the make-up supply water piping to the
unit for at least 5 minutes to remove construction debris.
• Before starting system the first time, flush the hCore™ Heat Transfer Technology for at
least 5 minutes to remove construction debris.
Cleaning and Inspection
• Ensure that the water diverter (see Figure 2) is free of dirt and debris.
• Flush the spray water basin interior to remove any accumulated dirt and debris. Use a
garden hose to remove any dirt and debris.
DANGER: Rotating equipment
will cause severe personal injury
or death to persons who come in
contact. Do not perform any service,
maintenance, or inspection on or
near the fan(s), motor(s), or inside
the unit without first ensuring
that the fans and pump motors
are disconnected, locked out, and
tagged out.
Figure 2. Water Diverter Figure 3. Spray Water Basin
Figure 4. Hinged Access Fan Panel
Water Diverter

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• Remove spray distribution access panels, and inspect and clean the spray branch,
nozzles, and drift eliminators as necessary.
• Remove all dirt and debris from the fan guard(s).
• Open hinged access fan panel (see Figure 4) to clean all mechanical components and
to remove dirt and debris from plenum area.
• The installation and manufacturing processes used for field assembly of steel-piped
systems may leave weld byproducts inside the hCore™ Heat Transfer Technology and
connecting piping. It is common practice to install filters and/or strainers that remove
contaminants during initial system operation. Shortly after system start-up, the filters
and/or strainers should be cleaned or replaced.
• Conduct external inspection of the equipment, sensors and probes. Check for leaks,
corrosion, and any structural damage.
• Conduct internal inspection of the equipment. Check for anything unusual such as
structural or mechanical component damage.
• Inspect wiring and connections for all the components.
• Confirm that wiring and connections inside of the iPilot™ Control System panel are
secured.
• Inspect riser pipe(s) and connections.
• Inspect process fluid manifold piping and connections.
• Thoroughly inspect the fan(s) and pump(s) for any mechanical or physical damage.
• Verify that fan(s) rotates freely.
• Inspect solenoid valves, make-up valves, drain valves, and level switches.
• Check that the mechanical make-up valve is operating freely.
Pre Start-up Checks
• Verify that the following items are
turned off and the unit is locked out/
tagged out:
–Supply power disconnect
–Fan motor(s)
–Pump motors
–iPilot™ Control System (control
panel)
–Basin heater control panel
(optional)
–Basin heaters (optional)
–Positive closure dampers
• Verify that all panels are closed and
secure, including the following:
–Fan access panel
–Spray distribution access panel
–Basin access cover
–iPilot™ Control System panel
door
–Heater control panel door (if ordered)
• Verify the following water connections:
–Solenoid make-up valve –
Incoming water pressure must
be between 20 and 75 psig
Figure 5. Panels to Secure
DANGER: Rotating equipment
will cause severe personal injury
or death to persons who come in
contact. Do not perform any service,
maintenance, or inspection on or
near the fans, motors, and drives,
or inside the unit without first
ensuring that the fans and pump
motors are disconnected, locked
out, and tagged out.
Start-Up & Operation
Start-Up
General
Cleaning and Inspection
Pre-Start-up Checks

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–Drain valve
–Overflow
• Turn the water supply on.
• Set the make-up float valve so the water shuts off at the operating level, see Table 2
on page 22 and Figure 17 on page 23.
• Ensure proper water treatment. Refer to page 30 for details.
• Verify the voltage stated in the submittal package matches the incoming power at the
job site.
• Verify that the supply power is connected to the iPilot™ Control System.
• Verify that Building Management System (BMS) interface is correctly wired to the
iPilot™ Control System.
• Turn on all breakers inside the iPilot™ Control System.
• Close the iPilot™ Control System panel and ensure that all the locks have been fully
engaged and secured by rotating them 90° with a flathead screwdriver or coin.
• Turn on the main power supply to the unit.
• Verify wiring from each component to the iPilot™ Control System.
• Verify component operation by entering the Main Menu of the user interface, select
Point Overview, and change Manual Mode to On. Refer to the “iPilot™ Control System
Appendix” on page 45.
• On units that are powered with 230/460V three phase, the power must be connected
properly to ensure that the pumps rotate clockwise. The wiring should be installed to
have incoming power U phase connected to panel L1, V phase to L2, W phase to L2,
and E phase to ground. It is recommended that a rotation meter be used to confirm
the power is connected to allow clockwise operation.
• Verify that fan(s) are rotating in the correct direction (clockwise when looking into the
unit from the outside) by operating each component in “Manual mode”.
• Check for unusual noise or vibration.
• After verifying component operation, re-enter the Main Menu and change Manual
Mode to Off and ensure that overational system value (OSV) is Off.
Start-Up
• For initial start-up, clean the conductivity sensor after two weeks of service.
• Ensure that main disconnect switch on the iPilot™ Control System is turned On.
The iPilot™ Control System will arrive onsite preconfigured with factory default values and
requires field setup. There are three methods of equipment control:
1. Local control without a Building Management System (BMS) interface
2. Local control with a BMS interface (See Table 15 on page 57 for the BMS
data points).
3. Customer Input: Control using analog input (0-10 VDC, 10-0 VDC,
or 4-20 mA) by others.
• Refer to “iPilot™ Control System Appendix” on page 45 for more information
including for controls connections.
• Anytime equipment operation is required, Run Enable must be turned On either
locally through the iPilot™ Control System interface or remotely with a signal by
others.
DANGER: Rotating equipment
will cause severe personal injury
or death to persons who come in
contact. Do not perform any service,
maintenance, or inspection on or
near the fans, motors, or inside
the unit without first ensuring
that the fans and pump motors
are disconnected, locked out, and
tagged out.
WARNING: Dangerous voltages
are present in this equipment.
Disconnect the electrical service
of the source and tag the circuit
out before servicing or replacing
components.