BAC Trillium Series Manual

TVFC Adiabatic Cooler
OPERATING AND MAINTENANCE INSTRUCTIONS
MTVFCv05EN

Recommended maintenance and
monitoring programme
Baltimore Aircoil Company equipment needs to be properly installed, operated and maintained. Documentation of
the equipment used, including a drawing, technical data sheet and this manual should be kept on record. To
achieve long, trouble-free and safe operation, it is necessary to establish an operating plan including a programme
of regular inspection, monitoring and maintenance. All inspections, maintenance and monitoring actions should be
recorded in a cooling system logbook. The operating and maintenance instructions published here can be used as
a guide to achieve these goals.
In addition to establishing the operating plan and the cooling system logbook it is recommended to conduct a
cooling system risk analysis, preferably by an independent third party.
For more specific recommendations on keeping your cooling system efficient and safe, contact your local BAC
Balticare service provider or representative. Name, e-mail and phone number can be found on the website
www.BACService.eu.
Checks and adjustments Start-Up Every
month
Every 3
months
Every 6
months
Every start of adiabatic
season, Spring
Adiabatic pre-cooler water flow X X X
Level switches (optional) X X
Tighten electrical connections X X X
Rotation of fan(s) X
Motor voltage and current X X X
Unusual noise and/or vibration X X X
Inspections and monitoring Start-up Every
month
Every 3
months
Every 6
months
Every start of adiabatic
season, Spring
General condition of the equipment X X X
Adiabatic pre-cooling pads X X X
Heat transfer coil X X
Water distribution pipe X X X
Float switch (ball can move freely) X X X
Cleaning procedures Start-up Every
month
Every 3
months
Every 6
months
Every start of adiabatic
season, Spring
Adiabatic pre-cooling media X X X
Adiabatic gutter system X X
Sump X X
Coil (remove dust) X
Auxiliary equipment integrated in the cooling system may require additions to the table above. Contact
suppliers for recommended actions and their required frequency.
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Table of contents
OPERATING AND MAINTENANCE INSTRUCTIONS
1 Construction details 4
2 General information 5
Operating conditions 5
Connecting pipework 5
Safety precautions 6
Disposal requirements 7
Non-walking surfaces 7
Modifications by others 7
Warranty 7
3 Water care 8
About water care 8
Biological control 10
Chemical treatment 10
4 Cold weather operations 11
About cold weather operation 11
Protection against coil freezing 11
Protection against pre-cooler freezing 11
Protection of electrical components 12
5 Operating instructions 13
TrilliumSeries Coolers with EC fans & factory installed control panel 13
Control logic 13
Electrical panels 13
Operating instructions Digital Controller 14
Monitoring of process information 14
6 Maintenance procedure 15
Checks and adjustments 15
Inspections and corrective actions 17
Fan replacement 19
Cleaning procedures 21
Adiabatic pre-cooling media 24
7 Comprehensive maintenance 26
About comprehensive maintenance 26
Prolonged outdoor stay 26
8 Further Assistance & Information 27
Assistance 27
More information 27
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CONSTRUCTION DETAILS
Details
1. Heat exchanger
2. Coil headers
3. Casing
4. Fans
5. Pre-cooler media
6. Pre-cooler drain valve
7. Pre-cooler drain
8. Pre-cooler flow valve/meter
9. Pre-cooler water distribution gutter
10. Pre-cooler water distribution pads
11. Ambient temperature sensor
12. Power panel
13. Control panel
14. Make-up
15. Recirculation pump (optional)
16. Flow switch (optional)
17. Level switch (optional)
18. Make-up flow balancing valve
19. Coil connections
4
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1 Construction details
1 Construction details

2 General information
2 General information W W W . B A L T I M O R E A I R C O I L . E U
5
GENERAL INFORMATION
Operating conditions
BAC cooling equipment is designed for the operating conditions specified below, which must not be exceeded
during operation.
•Wind Load: For safe operation of unshielded equipment exposed to wind speeds above 120 km/h installed at a
height above 30 m from the ground, contact your local BAC-Balticare representative.
•Seismic Risk: For safe operation of equipment installed in moderate and high hazard area's contact your local
BAC-Balticare representative.
Ambient temperature at continuous full speed; full load operation ranges from -10°C to+45°C. For cold climates, if
optional thermostatically controlled heaters are employed, the temperature range can be extended from -40°C
to+45°C.
HEAT EXCHANGER COIL
• Design pressure: 10 bar
• Maximum fluid inlet temperature: 60 °C
• Fluids circulated through the inside of the coils must be compatible with the coil construction material.
ADIABATIC PRE-COOLER OF TRILLIUMSERIES COOLER
• Design water supply pressure: 3-10 bar
• The water distributed on the adiabatic pre-coolers should be of potable supply.
• In case of non-treated water, the temperature should be kept below 20°C.
Connecting pipework
All piping external to BAC cooling equipment must be supported separately.
In case the equipment is installed on vibration rails or springs, the piping must contain compensators to eliminate
vibrations carried through the external pipework.
The equipment outlet piping must be installed under the operating level of the equipment to prevent air suction and
pump cavitation.
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Safety precautions
All electrical, mechanical and rotating machinery constitutes a potential hazard, particularly for those not familiar
with its design, construction and operation. Accordingly, adequate safeguards (including use of protective
enclosures where necessary) should be taken with this equipment both to safeguard the public (including minors)
from injury and to prevent damage to the equipment, its associated system and the premises.
If there is doubt about safe and proper rigging, installation, operation or maintenance procedures, contact the
equipment manufacturer or his representative for advice.
When working on operating equipment, be aware that some parts may have an elevated temperature. Any
operations on elevated level have to be executed with extra care to prevent accidents.
CAUTION
Surface of coil/piping can be hot.
AUTHORIZED PERSONNEL
The operation, maintenance and repair of this equipment should be undertaken only by personnel authorized and
qualified to do so. All such personnel should be thoroughly familiar with the equipment, the associated systems
and controls and the procedures set forth in this and other relevant manuals. 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. Personnel must use personal protective
equipment where necessary (gloves, ear plugs, etc...)
MECHANICAL SAFETY
Mechanical safety of the equipment is in accordance with the requirements of the EU machinery directive.
Depending upon site conditions it also may be necessary to install items such as bottom screens, ladders, safety
cages, stairways, access platforms, handrails and toe boards for the safety and convenience of the authorized
service and maintenance personnel.
At no time this equipment should be operated without all fan screens in place.
Since the equipment operates at variable speeds, steps must be taken to avoid operating at or near the
installation's "critical speed".
For more information consult your local BAC Balticare representative.
ELECTRICAL SAFETY
All electrical components associated with this equipment should be installed with a lockable disconnect switch
located within sight of the equipment.
In the event of multiple components, these can be installed after a single disconnect switch but multiple switches
or a combination thereof are also allowed.
No service work should be performed on or near electrical components unless adequate safety measures are
taken. These include, but are not limited to the following:
• Isolate the component electrically
• Lock the isolation switch in order to prevent unintentional restart
• Measure that no electrical voltage is present anymore
• If parts of the installation remain energized, make sure to properly demarcate these in order to avoid confusion
Fan motor terminals and connections may have residual voltage after unit shut-down. Wait five minutes after
disconnecting the voltage at all poles before opening the fan motor terminal box.
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LOCAL REGULATIONS
Installation and operation of cooling equipment may be subject to local regulations, such as establishment of risk
analysis. Ensure regulatory requirements are consistently met.
Disposal requirements
Dismantling of the unit and treatment of refrigerants (if applicable), oil and other parts must be done with respect to
the environment whilst protecting workers from potential risks related to exposure to harmful substances.
National and regional legislation for material disposal and protection of workers should be taken into account with
regard to:
• Appropriate handling of construction and maintenance materials when dismantling the unit. In particular when
dealing with materials that contain harmful substances, such as asbestos or carcinogenic substances.
• Appropriate disposal of the construction and maintenance materials and components such as steel, plastics,
refrigerants and waste water according to local and national requirements for waste management, recycling
and disposal.
Non-walking surfaces
Access to and maintenance of any component needs to be performed in accordance with all local applicable laws
and regulations. If the proper and required access means are not present, temporary structures need to be
foreseen. Under no circumstance can one use parts of the unit, that are not designed as an access mean, unless
measures can be taken to mitigate any risks that might occur from doing so.
Modifications by others
Whenever modifications or changes are made by others to the BAC equipment without written permission of BAC,
the party who has done the modification becomes responsible for all consequences of this change and BAC
declines all liability for the product.
Warranty
BAC will guarantee all products to be free from manufactured defects in materials and workmanship for a period of
24 months from the date of shipment. In the event of any such defect, BAC will repair or provide a replacement.
For more details, please refer to the Limitation of Warranties applicable to and in effect at the time of the
sale/purchase of these products. You can find these terms and conditions on the reverse side of your order
acknowledgement form and your invoice.
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2 General information
2 General information

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WATER CARE
About water care
The adiabatic pre-cooler of the unit has been designed as direct-water system, without water re-circulation, without
pump. Therefore it is essential that the main cold-water supply connected to the adiabatic pre-cooler has adequate
pressure and flow rate for the pre-cooler being installed.
The primary water treatment control method for the adiabatic pre-cooler is to provide sufficient water to the pre-
cooler medium to keep it flushed. If sufficient water is not provided to completely wet and flush the entire pre-
cooler medium surface, deposition will occur.
Many water related problems can be avoided if good system design and basic housekeeping practices are
followed. However, water treatment chemicals should NOT be used INSTEAD of following these practices:
• Provide, good, even water distribution (See table: Minimum recommended adiabatic pre-cooler water flow
rates)
• Clean distribution header on a regular basis
• Replace damaged or spent pre-cooler media
Refer to "Construction details" on page4. Mains cold water is supplied to (6), and is fed to the water distribution
system (9), via a flow valve/meter (8). The recommended mains water supply pressure is minimum 3 bar, and the
flow valve/meter (8) needs to be adjusted at installation to feed a minimum water flow over the adiabatic pre-cooler
(See table: "Minimum recommended adiabatic pre-cooler water flow rates")
The minimum water flow to be distributed over the adiabatic pre-cooler depends on:
• Climate conditions, i.e. evaporation rate at design conditions
• General water quality
• Water scaling tendency (practical scaling index)
The minimum water flow rates given in table "Minimum recommended adiabatic pre-cooler water flow rates", are
valid for the following operating conditions:
• Maximum ambient temperature of 35 ºC at minimum relative humidity of 30 %.
• Minimum supply water quality (See table below "Minimum supply water quality").
• Practical scaling index of 5.5 – 8.0.
To control corrosion and scale, the water chemistry of the circulated water has to be kept within the water quality
guidelines of the specific materials of construction used, as listed in the following table(s).
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3 Water care
3 Water care

Water quality guidelines for adiabatic
pre-cooler Frame
Baltibond®Hybrid Coating
Temperature < 20 ºC
PH 6.5 – 9
Hardness as (CaCO3) 30 – 500 mg/l
Alkaline as (CaCO3) < 500 mg/l
Total dissolved solids < 1500 mg/l
Chlorides < 200 mg/l
Sulfates < 300 mg/l
Conductivity 1800 µS/cm
Bacteria Rate (CFU/ml, KBE/ml) < 1000
Minimum supply water quality
For Ozone water treatment application:
• Stainless steel 316L execution is required.
• Ozone levels are to be maintained to 0.2 ppm ± 0.1 ppm for at least 90% of the time, with absolute maximum
peaks of 0.5 ppm
Recommended adiabatic pre-cooler water flow rates
If any of the following happens:
• at ambient conditions exceeding the given maximum ambient conditions,
• with supply water quality data exceeding one or more of the concentration limits of above table "Minimum
supply water quality",
• if the supply water has a Practical Scaling Index below 5.5,
Then:
• the water flow needs to be increased to higher levels to avoid rapid fouling and scaling of the pre-cooler
medium. Contact your local BAC-Balticare representative for support.
Data for rapid calculations of Practical Scaling Index for adiabatic pre-cooler
Conductivity
(µS/cm)
A
Temperature
ºC
B
Calcium hardness
(PPM as CaCO3)
C
Total alkalinity
(PPM as CaCO3)
D
Alkalinity
(PPM as CaCO3)
pHeq
50-300
301-1000
1001-3000
3001-5000
0.1
0.2
0.25
0.27
10-13
14-17
18-21
22-27
2.3
2.2
2.1
2.0
10-15
16-25
26-40
41-70
71-100
101-140
141-200
201-250
251-300
301-350
351-400
401-450
451-500
0.70
0.90
1.10
1.35
1.55
1.70
1.85
1.95
2.05
2.12
2.18
2.24
2.28
10-15
16-25
26-40
41-70
71-100
101-140
141-200
201-250
251-300
301-350
351-400
401-450
451-500
1.10
1.30
1.50
1.75
1.90
2.10
2.25
2.35
2.45
2.52
2.58
2.63
2.68
50
100
200
300
400
500
7.0
7.5
7.9
8.2
8.4
8.5
Calculation of Practical Scaling Index
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3 Water care
3 Water care

Instructions:
1. Obtain values of A, B, C and D from above tables
2. pHs = (9.3 + A + B ) – (C + D )
3. Practical Scaling Index = 2 pHs – pHeq
- if Index is 6.0, water is stable
- if Index is above 6.0, water is scale dissolving
- if index is below 6.0, water is scale forming
With Practical Scaling Index below 5.5, minimum recommended water flow in table "Minimum water flow rates"
needs to be increased, contact your local BAC-Balticare representative for support.
Biological control
The adiabatic pre-cooler and its controls have been designed to minimize the risk of uncontrolled growth of algae,
slimes and other micro-organisms such as Legionella:
1. No standing water
2. Complete drying of the pre-cooling system after each adiabatic cycle
3. Complete draining of all water distribution piping installed on the unit after each adiabatic cycle
CAUTION
The owner of the equipment is responsible for draining of all water piping feeding the adiabatic
pre-cooler to avoid stagnant water conditions.
4. Use of potable water supply at temperatures of 20 ºC or less, where Legionella is dormant
5. Aerosol free operation
When basic housekeeping practices are followed, and when the guidelines for operation and maintenance of this
bulletin are followed, problems related to uncontrolled growth of micro-organisms will be avoided.
Chemical treatment
A biocide program for biological control can be implemented in conjunction with the maintenance program for
increased operational safety. However, biological control should not be used in place of good housekeeping.
The two most commonly available biocides are chlorine and bromide. These chemicals have widespread success
in general application; however, caution should be practiced when using them in the adiabatic pre-cooling system.
Continuous dosages of chlorine or bromide could delignify the cellulose fibres of the pre-cooler media, and degrade
the stiffening agents.
RECOMMENDED CHLORINE / BROMIDE DOSAGES
Continuous Treatment: Not required when basic housekeeping practices are followed, and when the guidelines
for operation and maintenance of this bulletin are followed.
Shock Treatment: 3.0 – 5.0 PPM Free Halogens. Not recommended more often than once per quarter.
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4 Cold weather operations
4 Cold weather operations W W W . B A L T I M O R E A I R C O I L . E U
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COLD WEATHER OPERATIONS
About cold weather operation
BAC cooling equipment can be operated in sub freezing ambient conditions provided the proper measures are
taken. Listed below are general guidelines which should be followed to minimize the possibility of coil freeze-up.
As these guidelines may not include all aspects of the anticipated operation scheme, system designer and
operator must thoroughly review the system, location of the equipment, controls and accessories to ensure reliable
operation at all times.
Protection against coil freezing
The best protection is the use of glycol or other anti freeze solutions in appropriate concentrations. The use of such
solutions influences the thermal performance of the cooler and this should be taken into account, when selecting
the model(s). The table below indicates the freeze protection range for various ethylene glycol concentrations(%
by volume).
% Ethylene Freeze protection
20% -10°C
30% -16°C
40% -25°C
50% -39°C
Freeze protection of ethylene glycol solutions
Glycol systems require specific inhibitors compatible with the materials of construction they come into
contact with.These inhibitors generally come pre-mixed with the glycol additive for the cooling circuit.
If the process load is extremely light or shut off, it may be necessary to apply an auxiliary heat load during freezing
conditions. Consult your local BAC Balticare representative for advice.
On a standard unit, full coil drain of the heat exchangers is not possible and as such, this method cannot be
relied upon to protect fluid coolers operating under ambient temperatures that could drop below freezing
point, from damage to the coil.
Protection against pre-cooler freezing
The integrated controls automatically prevent adiabatic operation once the ambient temperature drops below 4°C.
No extra attention to the unit itself is required. It is of course advisable to take the necessary precautions with
regard to the piping towards the unit.
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Protection of electrical components
The components inside the electrical panel are designed to operate in ambient temperatures down to -10°C. In
case colder temperatures can be expected, the control panel needs to be equipped with a heating element in order
to avoid the temperature inside the panel to drop below -10°C.
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5 Operating instructions
5 Operating instructions W W W . B A L T I M O R E A I R C O I L . E U
13
OPERATING INSTRUCTIONS
TrilliumSeries Coolers with EC fans & factory installed
control panel
Control logic
The fan speed is controlled on the basis of the actual process fluid return temperature and the design return
temperature, ensuring a minimum electrical consumption and noise levels.
The adiabatic pre-cooling will be activated and stopped on the basis of a pre-programmed logical combination of
the fan speed and the ambient temperature (release set-point). Default settings will not activate adiabatic pre-
cooling unless all fans are running at maximum permissible speed and the dry-to-adiabatic release set-point is
reached.
The adiabatic control logic is pre-programmed and is ready for operation.
Depending on the actual size of the installation, the controller pre-programmed PIprocess parameters may need to
be adjusted.
Electrical panels
1. Power panel
2. Control panel
3. Digital controller with LCD interface
4. Optional heater (required for ambient temperatures
between -10°C and -40°C)
Electrical panel for unit with EC fans
CONTROL PANEL
The control panel contains the digital controller and the optional thermostat.
At the outside of the control panel, the following components can be found:
• Emergency stop: Push to activate; rotate to de-activate.
• Reset button (restart after emergency stop).
• 24VAC power indicator light.
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POWER PANEL
At the outside of the power panel, the following components can be found:
• ON/OFF switch
Operating instructions Digital Controller
There are different menu's:
• Main Loop Menu (readout unit status, temperatures, fan speed, etc...)
• Alarms (status of different alarms)
• User Menu (operational settings)
• Manufacturer Menu (not accessible)
• Clock
• System info
• Logger (alarm and warning history)
• Maintenance
• Working time (operating hours fans and adiabatic pre-cooling)
• Inputs/outputs
Please refer to the Software Instructions Manual (SI-TVFC) and the units specific parameter settings in
your submittal package.
CAUTION
Changing the controller's parameters may result in an undesired operation of the unit such as a
'hunting' phenomenon, premature activation of pre-cooling (hence increased water consumption)
or in late pre-cooling activation resulting in fluid outlet temperatures exceeding the design
temperature.
Monitoring of process information
DRY CONTACTS AT TERMINAL STRIP IN ELECTRICAL PANEL
• Input:
- Run authorization (NO)
- Free cooling (NO)
• Output:
- General Alarm (NO+NC)
- Warning (NO)
- Run Indication (NO)
DIGITAL BUS SYSTEM
A bus connection from the digital controller for monitoring can be wired to the terminal strip. Depending on the
required communication protocol, a different optional communications card can be installed in the controller.
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6 Maintenance procedure
6 Maintenance procedure W W W . B A L T I M O R E A I R C O I L . E U
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MAINTENANCE PROCEDURE
Checks and adjustments
ADIABATIC PRE-COOLER WATER FLOW
A minimum water flow must be distributed over the adiabatic pre-cooler as per minimum water flow rates. (See
table below "Minimum recommended adiabatic pre-cooler water flow rates").
The water flow will depend on the supply water pressure, and can be set with the 2 concentric hex screws on the
water flow valve on the flow meter. First open the plastic cover plate of the water flow adjustment screw.
Water flow adjustment screw
Model Number of
fans
Recommended pre-cooler water flow per unit
Once Through
Recirculation
Make-up Pump
TVFC-EC-8022-* 4 fans 14 l/min 14 l/min 40 l/min
TVFC-EC-8023-* 6 fans 22 l/min 22 l/min 60 l/min
TVFC-EC-8024-* 8 fans 28 l/min 28 l/min 80 l/min
TVFC-EC-8025-* 10 fans 36 l/min 36 l/min 86 l/min
TVFC-EC-8026-* 12 fans 44 l/min 44 l/min 104 l/min
TVFC-EC-8027-* 14 fans 50 l/min 50 l/min 121 l/min
Recommended adiabatic pre-cooler water flow rates
TVFC
6

LEVEL SWITCHES
Level switches are only available for recirculation units.
Two industrial grade stainless steel float switches maintain the water level in the sump between a minimum and
maximum level in order to make sure there is always enough water available to ensure a proper wetting of the pre-
cooler pads.
Both switches are factory set at the correct level.This can be verified visually or with the help of a tool like a screw
driver when the matching holes are properly aligned (see drawing below).
Measurements of the float switch construction
1. Matching holes
2. Witness mark
3. High level
4. Low level
Use a metal cylinder profile like a screwdriver to position high and low level float switch. Float switch
operation can be reversed, for correct operation witness mark is at the bottom.
The minimum and maximum water level can be adjusted for site specific conditions by changing the vertical
position of the float switches.
CAUTION
Changing the set points may lead to overflowing the basin, or damaging the pump(s).
Instructions to change the height:
1. Loosen the M8bolts
2. Adjust the vertical position of the float switch to the desired height
3. Tighten the M8bolts
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ADIABATIC PRE-COOLER SET-POINT
The operation of the adiabatic pre-cooling sections is controlled by the digital controller.
The controller should limit the start and stop to maximum 1 per day per adiabatic pre-cooling side, this to increase
the service life of the pre-cooler media. If the number of daily starts and stops exceeds 1 per day, it is
recommended that the controller's set points are adjusted. The pre-cooler can be operated to allow a higher number
of starts and stops which could reduce total annual water consumption, however, this practice will drastically
reduce the service lifetime of the adiabatic pre-cooler media.
ELECTRICAL CONNECTIONS
Check and tighten electrical contacts if required before commissioning the unit. Transport may loosen some of the
contacts, posing a risk for overheating or voltage drops. Also during operation, half-yearly checks are
recommended.
ROTATION OF FANS
Fans must rotate without obstruction in the direction indicated by arrows on the equipment.
MOTOR VOLTAGE AND CURRENT
Check the voltage and the current of all three legs of the fan motors. The current should not exceed the nameplate
rating. After prolonged shutdown the motor insulation should be checked with a Megger insulation tester prior to
restarting.
The voltage must not fluctuate more than +/-10% and the imbalance between phases must not be greater
than+/-2%.
CAUTION
Do not run/start the fan motor(s) when there is no heat load.
UNUSUAL NOISE AND VIBRATIONS
Unusual noise and/or vibration are the result of malfunctioning of mechanical components or operational problems
(e.g. unwanted ice formation). If this occurs, a thorough inspection of the entire unit followed by immediate
corrective action is needed. If required, consult your local BAC Balticare representative for assistance.
Inspections and corrective actions
GENERAL CONDITION OF THE EQUIPMENT
Once a year the general condition of the equipment should be inspected.
The inspection should focus on:
• Signs of corrosion
• Accumulation of dirt and debris
Smaller damages of the corrosion protection MUST be repaired as soon as possible to prevent the damage from
getting bigger. For Baltibond®hybrid coating use kit (part number RK1057). Larger damages should be reported to
the local BAC Balticare representative.
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6 Maintenance procedure
6 Maintenance procedure

ADIABATIC PRE-COOLING MEDIA
About Adiabatic Pre-Cooling
Airborne debris is caught in the adiabatic pre-cooling media. They act as an air filter and as such protect the heat
exchanger coil from rapid and excessive fouling. During adiabatic operation the media is 'rinsed' by water
overfeed. The debris, that is rinsed from the media, will drain together with the excess water.
The pre-cooling media can be removed during cold seasons, as soon as it is guaranteed that the ambient
temperature will no longer exceed the dry-to-adiabatic switch point. This will extend the service lifetime of the
media. It will however increase the speed of fouling of the dry heat exchanger coil.
At least every quarter an inspection of the adiabatic pre-cooler media is recommended, also during mid-season and
winter season when usually no adiabatic cycles would be needed.
The inspection should focus on:
• Signs of excessive fouling and scaling of the media
• Full and even wetting of the face area
Float switches
• Check that the float switches can move freely
Fouling
If excessive dirt and debris has accumulated on the pre-cooling media, it is recommended to rinse the media.
Refer to "Adiabatic pre-cooling media" on page24 for the recommended procedure for cleaning and rinsing of the
media.
Scaling
Scaling will deposit on the pre-cooling media, every time that the pre-cooling media dries at the end of each
adiabatic cycle. The rate of scaling will depend upon:
• The number of adiabatic starts and stops per day
• The water quality
• The water flow over the adiabatic pre-cooler
The expected service lifetime of the pre-cooling media is 5 to 7 years if basic housekeeping practices and these
operating and maintenance guidelines are followed.
If excessive scaling is accumulating too fast on the pre-cooling media, the following checks and adjustments need
to be made:
• Check and adjust number of adiabatic starts and stops:
refer to "Checks and adjustments" on page15, section "Adiabatic Controller Set-Point".
• Check and adjust water quality:
refer to section "About water care" on page8
• Check and adjust water flow distributed over Adiabatic Pre-Cooler:
refer to section "About water care" on page8.
HEAT EXCHANGER COIL
The finned heat exchanger coil is susceptible to corrosion and entrapment of airborne particulates (coil fouling).
The speed of coil fouling can be reduced, and the service lifetime of the finned coil can be extended, if the pre-
cooling media is kept in place also during cold seasons, to act as air filter.
The heat exchanger coil requires periodic cleaning to maintain the highest operating efficiency possible under the
environmental conditions in which the dry unit operates. Regularly scheduled coil cleaning makes a significant
contribution to extending equipment lifetime and is an excellent source of energy conservation.
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Periodic cleaning of the heat exchanger coil can be accomplished by a vacuum cleaner and/or pressurised air
stream. In polluted environments cleaning will require commercially available coil cleaning agents. Cleaning coils
by spraying them with water may remove large deposits but do little to remove pollutants. Removing dirt and salts
requires a detergent to break the bond between the soil and the surface of the heat exchanger. However, if water
spray is applied, the water pressure must never exceed 2 bar and the water jet must never be applied at an angle to
the surface of the fin, but only in parallel to it.
Selecting a coil cleaner is important since the cleaner must neutralise and remove deposits on the surface of the
coil. BAC does not recommend the use of alkaline and acidic coil cleaners. These coil cleaners can cause foaming
action (oxides or hydroxides of aluminium) resulting in the stripping away of minute layers of the base alloy and the
attached soil. Most of these foaming cleaners are harsh and known as reactive cleaning products. One way to
recognise this type of cleaner is that normally it will be labelled as corrosive. The base ingredient of a coil cleaner
should not be so harsh that it attacks the metal, coil coating or the personnel applying the cleaner.
An important concern when applying coil cleaners is rinse-ability. Most hydroxides tend to cling the surface unless
sufficient wetting agents have been added to the formula to reduce surface tension of the solution. If the solution
does not have enough wetting agents and is not rinsed thoroughly from the surface, the residual material can settle
at the fin/tube interface and continue to attack the fin.
BAC recommends the use of the more sophisticated cleaners, known as a "surfactant system". They reduce
surface tension, penetrate, emulsify, and dissolve the soils without the base alloy. Surfactant systems are safe for
the coil alloy, they are free rinsing, they lift and remove deposits better than alkaline cleaners, and they are
environmentally safe, as well as safe and easy to apply and rinse. Surfactant systems are almost always non-
corrosive.
Fan replacement
In case of replacement, any safety hazards stemming from the fan must be re-evaluated once it is installed on the
cooler.
Observe the following when working on the fans:
• Do not make any modifications, additions or conversions to the fan without the approval of the cooler
manufacturer.
• Terminals and connections may have residual voltage after unit shutdown.
Wait five minutes after disconnecting the voltage at all poles before opening the fan.
• In the event of failure, there is electric voltage at the rotor and impeller.
Do not touch the rotor and impeller once they are installed.
• Shut down the fan immediately if you detect a missing or ineffective protective feature.
The fans are controlled via a digital bus system (MODBUS RTU).
For the bus communication each fan needs to be assigned a unique address, starting with "2, 3, 4…….", leaving 1
free for any replacement fan. The sequence of the above system is shown on the diagram below.
In case of a fan replacement it will be necessary to specify the assigned fan number shown on the diagrams, so
that the replacement fan will be programmed accordingly.
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6 Maintenance procedure
6 Maintenance procedure

A. Control Panel
B. 4 Fan Unit
C. 6 Fan Unit
D. 8 Fan Unit
E. 10 Fan Unit
F. 12 Fan Unit
G. 14 Fan Unit
Diagram showing sequence of fan motor address Schematic of internal motor terminal strip
No. Conn. Designation Function / assignment
KL 1 1 L1 Mains supply connection, supply voltage 3~380÷480 VAC; 50/60 Hz
KL 1 2 L2 Mains supply connection, supply voltage 3~380÷480 VAC; 50/60 Hz
KL 1 3 L3 Mains supply connection, supply voltage 3~380÷480 VAC; 50/60 Hz
PE PE Earth connection, PE connection
KL 2 1 RSA Bus connection RS-485, RSA, MODBUS RTU; SELV
KL 2 2 RSB Bus connection RS-485, RSB, MODBUS RTU; SELV
KL 2 3 GND Signal ground for control interface, SELV
Kl 2 4 C Status relay; floating status contact; changeover contact; common
connection; contact rating 250 VAC / 2 A (AC1)
KL 2 5 Din1 Digital input 1 enabling of electronics
Enabling: open pin or applied voltage 5-50 VDC
Disabling: bridge to GND or applied voltage < 1 VDC
Reset function: triggers software reset after a level change to <1 V;
SELV
KL 2 6 + 10 V Fixed voltage output 10 VDC, +10V ±3%, max. 10 mA, short circuit-
proof, power supply for external devices (e.g. potentiometer), SELV
KL 2 7 Ain U Analogue input 1 (set value) 0-10 V, Ri=100 kΩ, parametrizable
curve, only usable as alternative to input Ain1 SELV
KL 2 8 NC Status relay, floating status contact, break for failure
Legend for internal motor terminal strip
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