Baltimore Aircoil Company Trillium Series Manual

DFCV-AD-EC Adiabatic Cooler
OPERATING AND MAINTENANCE INSTRUCTIONS
MDFCV-EC-ADv06EN

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
Adiabatic controller set-point X 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
City water strainer X X X
Check each fan for damage to blades & housing X
Check the insulation of fan wires for damage X
Tightness of fan screwed cable glands X
Condensate discharge holes for clogging 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
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 6
Non-walking surfaces 7
Modifications by others 7
Warranty 7
3 Water care 8
About water care 8
Biological control 10
Chemical treatment 11
4 Cold weather operations 12
About cold weather operation 12
Protection against coil freezing 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 15
6 Maintenance procedure 17
Checks and adjustments 17
Inspections and corrective actions 19
Fan replacement 20
Cleaning procedures 22
Adiabatic pre-cooling media 27
7 Comprehensive maintenance 30
About comprehensive maintenance 30
Prolonged outdoor stay 30
8 Further Assistance & Information 31
Balticare 31
More information 31
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W W W . B A L T I M O R E A I R C O I L . E U
CONSTRUCTION DETAILS
1. Heat exchanger
2. Coil headers
3. Casing
4. Fans
5. Pre-cooler media
6. Pre-cooler solenoid valve and water filter
7. Pre-cooler drain
8. Pre-cooler flow valve/meter
9. Pre-cooler water distribution header
10. Pre-cooler water distribution pads
11. Ambient temperature sensor
12. Power panel
13. Control panel Details
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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 working pressure: 21 bar
• Design test pressure: 30 bar
• Design temperature: -20°C / +120°C
ADIABATIC PRE-COOLER OF TRILLIUMSERIES COOLER
• 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.
• Design pressure: 3-7 bar
• Maximum fluid inlet temperature: +/- 20°C
• The water distributed on the adiabatic pre-coolers should be of potable supply.
• Water temperature not to exceed 20°C to avoid microbiological proliferation.
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.
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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.
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
No service work should be performed on or near the fans unless motors are electrically isolated.
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.
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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
• Clean city water strainer 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
Baltiplus 800™ coating
Temperature < 20 ºC
PH 6.5 – 9
Hardness as (CaCO3) 50 – 500 mg/l
Alkaline as (CaCO3) < 500 mg/l
Total dissolved solids < 1500 mg/l
Chlorides < 200 mg/l
Sulfates < 250 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.
Model Number of fans Minimum pre-cooler water flow
per unit
DFCV-EC9122-* 4 fans 14 l/min
DFCV-EC9123-* 6 fans 22 l/min
DFCV-EC9124-* 8 fans 28 l/min
DFCV-EC9125-* 10 fans 36 l/min
DFCV-EC9126-* 12 fans 44 l/min
DFCV-EC9127-* 14 fans 50 l/min
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.
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3 Water care
3 Water care

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
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. Direct water system, no water recirculation
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.
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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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3 Water care
3 Water care

W W W . B A L T I M O R E A I R C O I L . E U
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.
A 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.
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4 Cold weather operations
4 Cold weather operations

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
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OPERATING INSTRUCTIONS
TrilliumSeries Coolers with EC fans & factory installed
control panel
Each unit is equipped with a control panel and a power panel.
The fan speed is controlled and the adiabatic pre-cooling is activated by a PLC integrated into the electrical panel.
Control logic
The fan speed is controlled on the basis of the actual process fluid temperature at the exit of the unit and the design
leaving temperature, ensuring a minimum in 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
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CONTROL PANEL
The control panel contains the digital controller.
At the inside of the control panel, the following component can be found:
• Pad Maintenance Switch (DVW)
- AUTO(II): Pads will be (de)activated based on the units programming
- HAND(I): Pads will be forced in wet mode resulting in adiabatic operation
Pad Maintenance Switch (DVW) for EC fans
POWER PANEL
At the outside of the power panel, the following components can be found:
• Emergency stop:
Push to activate; rotate to de-activate
• Power failure reset:
After a loss of main power, the unit may not start automatically. This button needs to be pressed after a
technician has verified that it is safe to restart the unit.
• ON/OFF switch
Operating instructions Digital Controller
There are four different menu's:
• Default Menu (consultation)
• Operator Menu (operational settings)
• Factory Menu (not accessible)
1. Alarm
2. Programme
3. Escape
4. Down
5. Up
6. Enter
Symbols on digital controller
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DEFAULT MENU
The overview of different operational parameters and their settings (ex: temperatures, set point, theoretical
frequency, actual frequency, and some general statuses)
ALARMS
This menu can be accessed by pressing on the Alarm button (Triangle with exclamation mark).
To acknowledge an alarm, press the Alarm button (Triangle with exclamation mark). If the source of the alarm has
disappeared, so will the alarm message, otherwise the alarm will stay present.
OPERATOR MENU
To access this menu press .
After you select the desired menu, press .
You can return to the default menu by pressing .
Before you can enter the actual menu, a password needs to be given. The standard password is "1234"
The following items are available:
• Local on/off
• Set point (both summer and winter)
• PI parameters
• Cleaning cycle activation/deactivation + duration
• Day/night operation activation/deactivation + start/stop
• Day/night operation maximum frequency
• Restriction on water usage period
• Status of pre-cooler authorization
• Time delay on alarm messages
• Reset function on internal timers (VFD, pre-coolers)
• Communication address + baud rate
• Time/date
• Change access code
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:
- Free cooling (NO)
• Output:
- General Alarm (NO+NC)
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5 Operating instructions
5 Operating instructions

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
17
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 by adjusting the adjustment screw on the
water flow valve on the flow meter (See figure below). Read off the water flow at the underside of the float.
Water flow adjustment screw
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Model Number of fans Minimum pre-cooler water flow
per unit
DFCV-EC9122-* 4 fans 14 l/min
DFCV-EC9123-* 6 fans 22 l/min
DFCV-EC9124-* 8 fans 28 l/min
DFCV-EC9125-* 10 fans 36 l/min
DFCV-EC9126-* 12 fans 44 l/min
DFCV-EC9127-* 14 fans 50 l/min
Recommended adiabatic pre-cooler water flow rates
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.
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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
If there are any signs of blemishes or corrosion, the affected area should be thoroughly wire brushed and re-coated.
The recommended procedure is to use a base coat of ZRC (Zinc Rich Compound). The ZRC is available from your
local BAC-Balticare representative.
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
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27 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17, 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.
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6 Maintenance procedure
6 Maintenance procedure

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.
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.
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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