BAC HXI Series Manual

HXI Hybrid Closed Circuit Cooling Tower
OPERATING AND MAINTENANCE INSTRUCTIONS
MHXIv10EN-SA

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 the cooling system, scale, corrosion and biological control must be established and initiated when the system
is first filled with water and administered on a regular basis thereafter in accordance with recognized Codes of
Practice, (such as EUROVENT 9 - 5/6, ACOP HSC L8, Guide des bonnes pratiques, Legionella et tours
aéroréfrigérantes, etc.). Water sampling, test results and corrective actions should be recorded in the cooling
system logbook.
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. or www.BaltimoreAircoil.co.za.
Checks and Adjustments Start-Up Weekly Monthly Quarterly Every 6
Months
Annually Shutdown
Cold Water Basin and Basin Strainers X X
Operating level and make-up X X
Blow down X X
Sump heater Package X X
Belt tension X X
Drive alignment X X
Locking Collar X
Rotation of fan(s) and pump(s) X
Motor voltage and current X X
Unusual noise and/or vibration X X
Inspections and Monitoring Start-
Up
Weekly Monthly Quarterly Every 6
Months
Annually Shutdown
General condition X X
Heat transfer section and drift eliminators X X
Finned discharge coil X X
Combined Inlet Shields X X
Water distribution X X
Fan shaft & Axial Fan X X
Fan Motor X X
Spray Water Pump X X
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Inspections and Monitoring Start-
Up
Weekly Monthly Quarterly Every 6
Months
Annually Shutdown
Electric Water Level Control Package (option) X X
TAB test (dip slides) X X
Circulating water quality X X
System overview X X
Recordkeeping as per event
Lubrication Start-Up Weekly Monthly Quarterly Every 6
Months
Annually Shutdown
Fan shaft bearings X X X
Motor bearings* X X
Adjustable motor base X X X
* only for motors with grease fittings with typical frame size > 200L (>30 kW)
Cleaning procedures Start-Up Weekly Monthly Quarterly Every 6
Months
Annually Shutdown
Mechanical cleaning X X X
Disinfection** (X) (X) (X)
Drain Basin X
** depends on applied code of practice
Notes
1. Water Treatment and auxiliary equipment integrated in the cooling system may require additions to the table
above. Contact suppliers for recommended actions and their required frequency.
2. Recommended service intervals are for typical installations. Different environmental conditions may dictate
more frequent servicing.
3. When operating in ambient temperatures below freezing, the unit should be inspected more frequently (see
Cold Weather Operations in the appropriate Operating and Maintenance Instructions).
4. For units with Belt Drive, tension on new belts must be readjusted after the first 24 hours of operation and
monthly thereafter.
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Table of Contents
OPERATING AND MAINTENANCE INSTRUCTIONS
1 Construction Details 5
Hybrid Closed Circuit Cooling Towers 5
2 General Information 6
Operating Conditions 6
Connecting Pipework 7
Safety Precautions 8
Disposal Requirements 9
Non-walking Surfaces 9
Modifications by others 9
Warranty 9
3 Water Care 10
About Water Care 10
Biological Control 12
Chemical Treatment 12
Passivation 12
4 Cold Weather Operations 14
About Cold Weather Operation 14
Protection Against Sump Water Freezing 14
Capacity Control 14
Protection Against Coil Freezing 15
5 Maintenance Procedures 18
Checks and Adjustments 18
Inspections and Corrective Actions 26
Lubrication 32
Cleaning Procedures 34
6 Comprehensive Maintenance 35
About Comprehensive Maintenance 35
Prolonged Outdoor Stay 35
7 Further Assistance & Information 36
Balticare 36
More Information 36
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1 Construction Details
1 Construction Details W W W . B A L T I M O R E A I R C O I L . C O . Z A
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CONSTRUCTION DETAILS
Hybrid Closed Circuit Cooling Towers
1. Air In
2. Air Out
3. Liquid In
4. Liquid Out
5. Wet Deck Surface
6. Cold Water Basin
7. Water Distribution System
8. Prime Surface coil
9. Spray Water Pump
10. Eliminators
11. Dry Finned Coil
12. Orifice Plate
13. Fan Motor for Axial Fan
15. Combined Inlet Shields
16. Motorized 3-Way Valve
17. Temperature Controller
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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.
Standard electrical motors are suitable for an ambient temperature range from -25°C to +40°C.
PRIME SURFACE COIL
Design pressure: max. 10 bar
Fluid inlet temperature: max. 82°C
Fluid outlet temperature: min. 10°C
Fluids circulated through the inside of the coils must be compatible with the coil construction material, ie.
• black steel, for hot dip galvanized coils
• stainless steel AISI 304L or 316L (options)
• copper tubes when units are fitted with the optional finned discharge coil
Maximum spray pressure: 14 kPa (If pump(s) are installed by others, it is recommended to install a pressure gauge
at the inlet of the water distribution system.)
DRY FINNED COIL
The standard dry finned coil on the HXI Hybrid closed circuit cooling tower consists of a 6 row copper coil in a
staggered "triangle" arrangement with precoated aluminum high density fins. The coil is designed in accordance to
PED regulations and has an operating pressure of 10 bar.
OPERATING MODES
The hybrid closed Circuit Fluid Cooler operates under three different operating modes:
1. Combined Dry-Wet Mode: During this mode, the process fluid flows through the finned coil bundle (sensible
heat transfer) and then through the wetted prime surface coil bundle (sensible and latent heat transfer). With
lower heat loads and/or ambient temperatures, the evaporative cooling portion (and hence the water usage) is
reduced by keeping the flow fed through the wetted prime surface coil bundle to a minimum. This is
accomplished by a modulating flow control valve, which controls the design outlet temperature.
2. Adiabatic Mode: During this mode, the process fluid flows through the finned coil bundle and by-passes the
wetted prime surface coil bundle completely. This entering ambient air is pre-humidified (cooled) by the spray
water before flowing over the high density finned coil bundle.
3. Dry Mode: The full process fluid flows through the finned coil bundle and the prime surface coil bundle. Since
the spray pump is turned off, only sensible heat transfer is used.
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SEASONAL PERIODS
The optimal operation of the Hybrid Closed Circuit Cooling Tower is obtained by a combination of the above
mentioned operating modes, depending on the thermal load of the process fluid and the ambient conditions.
Typically two different seasonal periods are distinguished from each other:
1. Summer period: During this period all three operating modes are applied and as such the spray pump is
activated during the dry/wet and the adiabatic operating mode. Therefore the cold water basin is filled with
water at all time.
2. Winter period: during this period only the dry operating mode is applied and as such the cold water basin is
drained.
The following table summarises the use of the different operating modes during the seasonal periods.
Summer Period Winter Period
Dry Mode Adiabatic Mode Dry/Wet Mode Dry Mode
Fan Motors Full / Half /
Variable Speed Full Speed Full Speed Full / Half /
Variable Speed
Spray Pump Motor Off On On Off
Process Fluid through
Finned Coil Bundle
100%
Design Flow
100%
Design Flow
100%
Design Flow
100%
Design Flow
Process Fluid through Bare
Coil Bundle
100%
Design Flow
(2)
0%
Variable
Flow
(1)
100%
Design Flow
(2)
Use of different Operating Modes during the Seasonal Periods
(1) Process fluid flow through bare coil bundle is controlled by the three way valve and is in function of the process fluid return temperature.
(2) The three way valve is locked and closes the bypass line completely.
When working dry during winter, the sump should be drained and power to the pump and heaters should be
switched off. If not, heat tracing should be foreseen.
Frequent on/off cycling of the spray pump should be limited to a minimum operating period of 5 hours.
Rapid on/off cycling of the fan motors can cause the fan motors to overheat. This should be limited to a
maximum of six on/off cycles/h. If the limit is equipped with 2-speed fan motors, a 15 seconds delay should be
observed when switching from high to low speed.
PURGE REQUIREMENTS
The installer of BAC closed circuit cooling towers must ensure a proper air purging of the system prior to operation.
Entrained air can restrict the capacity of the cooler, resulting in higher process temperatures.
All connections (installed by others) must be leak free and tested accordingly.
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.
Suction pipe sizing should be done according to good practice, which may for larger flows require larger pipe
diameters than the outlet connection. In such cases adapter pieces need to be installed.
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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
DO NOT COVER UNITS WITH PVC ELIMINATORS OR FILL WITH A PLASTIC TARPAULIN.
TEMPERATURE INCREASE DUE TO SUN RADIATION COULD DEFORM THE FILL OR
ELIMINATORS.
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, access panels and access doors in place.
When the equipment is operated with a variable fan speed control device, steps must be taken to avoid operating
at or near to the fan's «critical speed».
For more information consult your local BAC Balticare representative.
ELECTRICAL SAFETY
Each fan and pump motor associated with this equipment should be installed with a lockable disconnect switch
located within sight of the equipment. No service work should be performed on or near the fans, motor, drives or
inside the equipment unless fan and pump motors, heaters etc. are electrically isolated.
LOCATION
All cooling equipment should be located as far away as possible from occupied areas, open windows or air intakes
to buildings.
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.
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Disposal Requirements
Dismantling of the unit and treatment of refrigerants, 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
12 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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WATER CARE
About Water Care
In all cooling equipment, operating in evaporative mode, the cooling is accomplished by evaporating a small portion
of the re-circulating water as it flows through the equipment. When this water evaporates, the impurities originally
present in the water remain. Unless a small amount of water is drained from the system, known as blow down, the
concentration of dissolved solids will increase rapidly and lead to scale formation or corrosion or both. Also, since
water is being lost from the system through evaporation and blow down, this water needs to be replenished.
The total amount of replenishment, known as make-up, is defined as:
Make-up = evaporation loss + blow down
In addition to the impurities present in the make-up water, any airborne impurities or biological matter are carried
into the equipment and drawn into the re-circulating water. Over and above the necessity to blow down a small
quantity of water, a water treatment programme specifically designed to address scale, corrosion and biological
control should be initiated when the system is first installed and maintained on a continuous base thereafter.
Moreover there must be an ongoing programme of monitoring in place to ensure the water treatment system is
maintaining the water quality within the control guidelines.
Check and adjustments of blow down depends on the blow down device actual in use.
To prevent excessive build-up of impurities in the circulating water, a small amount of water must be « bled » from
the system at a rate to be determined by the water treatment regime. The amount of blow down is determined by
the design cycles of concentration for the system. These cycles of concentration depend on the quality of the
make-up water and the design guidelines for the quality of the recirculating water given below.
Make-up water to the evaporative unit should have minimum 30 ppm hardness as CaCO 3.
Where use of a softener is necessary to achieve this, the supply to the evaporative unit should not be totally
softened, but blended with the incoming unsoftened water to achieve the minimum hardness between 30 and
70 ppm as CaCO3.
Maintaining a minimum hardness in the make-up water offsets the corrosive properties of totally softened water
and reduces the reliance on corrosion inhibitors to protect the system.
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).
Baltiplus 800™/810™ Protection
pH 6.5 to 9.0
pH during initial passivation Below 8.2
Total hardness (as CaCO3) 50 to 600 mg/l
Total alkalinity (as CaCO3) 500 mg/l max.
Total Dissolved Solids 1500 mg/l max.
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Baltiplus 800™/810™ Protection
Conductivity 2400 µS/cm
Chlorides 250 mg/l max.
Sulfates* 250 mg/l max.*
Total Suspended Solids 25 mg/l max.
Chlorination (as free chlorine): continuous 1 mg/l max.
Chlorination (as free chlorine): batch dosing for cleaning &
disinfection
5-15 mg/l max. for 6 hours max.
25 mg/l max. for 2 hours max.
50 mg/l max. for 1 hour max.
Circulated Water Quality Guidelines for Baltiplus800™/810™Protection
*Note: Higher concentration of sulfates is allowed provided the sum of chlorides + sulfates parameters does not exceed 500 mg/l for
Baltiplus800™/810™ Protection.
SST316
pH 6.5 to 9.5
Total hardness (as CaCO350 to 750 mg/l
Total alkalinity (as CaCO3) 600 mg/l max.
Total Dissolved Solids 2500 mg/l max.
Conductivity 4000 µS/cm
Chlorides 750 mg/l max.
Sulfates* 750 mg/l max.*
Total Suspended Solids 25 mg/l max.
Chlorination (as free chlorine): continuous 2 mg/l max.
Chlorination (as free chlorine): batch dosing for
cleaning & disinfection
5-15 mg/l max. for 6 hours max.
25 mg/l max. for 2 hours max.
50 mg/l max. for 1 hour max.
Circulated Water Quality Guidelines for Stainless Steel
*Note: Higher concentration of sulphates is allowed provided the sum of chlorides + sulphates parameters does not exceed 650 mg/l for
SST304 and 1500 mg/l for SST316.
For Ozone water treatment application, stainless steel 316 execution is required.
Cycles of concentration are the ratio of the dissolved solids concentration in the circulating water compared to the
dissolved solids concentration in the make-up water. The blow down rate can be calculated as follows:
Blow down = Evaporation loss / (Cycles of concentration – 1)
The evaporation loss is not only function of the heat load but also depends on climatic conditions, the type of
equipment used and the method of capacity control, which is applied. The evaporation loss at summer conditions
is approximately 0.431 l/ 1000 kJ heat rejection. This number should be used for blow down valve sizing only and
not for the calculation of annual water consumption.
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Biological Control
The growth of algae, slimes and other micro-organisms, if uncontrolled, will reduce system efficiency and may
contribute to the growth of potentially harmful micro-organisms, such as Legionella, in the recirculating water
system.
Accordingly a treatment programme specifically designed to address biological control should be initiated when the
system is first filled with water and administered on a regular base thereafter in accordance with any regulations
(national, regional) that may exist or in accordance with accepted codes of good practice, such as EUROVENT
9-5/6, VDMA Detailsheet 24649 etc.
It is strongly recommended to monitor the bacteriological contamination of the recirculating water on a regular base
(for example, TAB test with dip slides on a weekly base) and record all results.
Water treatment should meet the following requirements:
Certain products used for water treatment, particular some dispersant and bio-dispersant additives, might change
the properties of the water (such as the surface tension), which can cause excessive drift loss (water passing
through the eliminators). In such case we recommend to review the water treatment (product type, dosage) with
your water treatment expert.
In case of doubt, a short test can be performed, after cleaning & disinfection, using fresh water without addition of
the concerned chemical (within the limits of the local legislation).
Chemical Treatment
1. Water treatment chemicals or non-chemical systems need to be compatible with the materials of construction
used in the cooling system including the evaporative cooling equipment itself.
2. In case of chemical water treatment, chemicals should be added to the recirculating water by an automatic
feed system. This will prevent localised high concentrations of chemicals, which may cause corrosion.
Preferably the water treatment chemicals should be fed into the cooling system at the discharge of the
recirculation pump. The chemicals should not be fed in concentrated form, nor batch fed directly into the cold
water sump of the evaporative cooling equipment.
3. BAC specifically discourages acid dosing as mean of scale control (unless under certain strict circumstances
for open circuit cooling towers with very large system volume and remote sump, or constructed from stainless
steel).
4. A competent water treatment company should be consulted for the specific water treatment programme to be
applied. Next to the supply of dosing and control equipment and chemicals, the programme should include
regular monthly monitoring of the circulating and make up water quality.
5. If it is proposed to operate a treatment programme outside the BAC Water Quality Control Guidelines, the BAC
factory warranty may be invalidated if the water quality is persistently outside the Control Guidelines, unless
specific prior written BAC approval. (Some parameters may be exceeded under certain strict circumstances.)
It is strongly recommended to check the key parameters of the circulating water quality on a monthly base. See
table: "Circulated Water Quality Guidelines". All test results need to be recorded.
Passivation
When new systems are first commissioned, special measures should be taken to ensure that galvanized steel
surfaces are properly passivated to provide maximum protection from corrosion. Passivation is the formation of a
protective, passive, oxide layer on galvanized steel surfaces.
To ensure that galvanized steel surfaces are passivated, the pH of circulating water should be kept between 7.0
and 8.2 and calcium hardness between 100 and 300 ppm (as CaCO3) for four to eight weeks after start-up, or until
new zinc surfaces turn dull grey in colour. If white deposits form on galvanized steel surfaces after the pH is
returned to normal service levels, it may be necessary to repeat the passivation process.
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Stainless steel units and units protected by the BALTIBOND®hybrid coating without galvanized coil, do
not require passivation.
In case you can't keep the pH below 8.2, a secondary approach is to conduct a chemical passivation using
inorganic phosphate or film-forming passivation agents. Consult your water treatment specialist for specific
recommendation.
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COLD WEATHER OPERATIONS
About Cold Weather Operation
BAC equipment can be operated in subfreezing ambient conditions provided the proper measures are taken:
1. Protection against sump water freezing, when the system is idle.
2. Capacity control to prevent ice formation during operation.
3. Protection against coil freezing.
Listed below are general guidelines which should be followed to minimize the possibility of 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 Sump Water Freezing
To prevent sump water from freezing, either sump heaters or a remote sump located in a heated indoor area must
be installed. For a seasonal shut down during the cold weather period, it is recommended to drain the sump.
Drainage of the sump will also be needed if dry operation is anticipated, even if sump heaters are installed. These
heaters will NOT prevent sump water from freezing during dry operation at sub-freezing ambient conditions.
Remote sump installations are best suited for a flexible switch from wet to dry operation, as the sump water is
protected at all times.
For dry operation applications, ensure that make-up water line is shut off and make-up valve completely drained.
Thermostats for electrical sump heaters for this equipment are to be set to maintain a sump water temperature of
4°C.
Caution
SWITCH OF HEATERS WHEN THE SUMP IS DRAINED..
Capacity Control
In addition to protecting the sump water, all exposed water piping, in particular make-up water lines should be heat
traced and insulated.
Spray pumps also need to be heat traced and insulated from pump suction to the overflow level, if they can be
exposed to sub-freezing ambient conditions.
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It is necessary to prevent the recirculating water from approaching freezing conditions when the system is
operating under load. The most « critical » situation occurs, if operation at subfreezing conditions coincides with
light load conditions. The key to protecting the recirculating water is capacity control by adjustment of air flow to
maintain the temperature of the recirculating water minimal above freezing point. As a rule of thumb this minimum
temperature is 5°C, but there are applications, where even lower temperatures can be accepted. (Contact your
local BAC Balticare representative for advice.)
The desired method to match the cooling capacity to load and weather conditions is to adjust the air flow, either by
cycling of the fan(s) (but always for ALL the fans on a specific cell), the use of multi speed fan motors or
modulating controls (variable speed drives).
It is not recommended to cycle the spray pump as a means of controlling the unit capacity.
Whenever two speed motors are used for capacity control, a time delay of at least 15 seconds is required when
switching form high to low speed. Sudden switch over might damage the drive system or the motor.
When the equipment is operated with a variable fan speed control device, steps must be taken to avoid both
operating at or near to the fan's «critical speed» and below a minimum of 15 Hz for a belt driven unit (or direct
driven fans) or 20 Hz for a unit with gear box. For more information consult your local BAC Balticare
representative.
When operating with VFD drives above nominal frequency be aware of the potential risk for motor overload
or mechanical damages.
It is recommended to provide sinus filters on the VFD to prevent bearing damage on fan motors.
Caution
REFER TO FAN MOTOR NAMEPLATE DATA WHEN PROGRAMMING A VFD
The purpose of a Low Level Cut out Switch for pump protection is to protect the pump from running dry in case of
make-up failure or extreme water loss. The status of the alarm can be checked prior to pump start-up, but should
not be considered during the first minute after start-up, since activation of the pump can cause a water level drop,
that might trigger the alarm. Normal make-up will stabilize the water level after a short period of time.
In case the low level alarm signals, that there is no longer enough water in the cold water sump to guarantee a
proper operation, the pump should be stopped (after a time delay of 60 seconds) and only manually restarted after it
has been verified that the water in the sump is at or near the overflow level.
In case the low level pump alarm is used to stop the pump, appropriate control logic should be incorporated
to prevent hunting of the pump motor. Once the spray pump is stopped, the water in suspension will drain
back to the tank and raise the water-level above the alarm level, which will reset the alarm immediately. A manual
reset of the alarm after solving the root cause of the low level alarm is recommended. Frequent start/stop or
hunting will damage the motor.
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 closed circuit cooling tower 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)
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% Ethylene Freeze Protection
20% -10°C
30% -16°C
40% -25°C
50% -39°C
Freeze Protection of Ethylene Glycol Solutions
If the system must be operated with water, the following conditions must be met simultaneously:
1. Maintain a minimum flow through the unit at all times. (see table below)
2. Maintain a minimum heat load, so that the temperature of the water leaving the coil(s) will not fall below 10°C
based on -14°C ambient temperature and 20 m/s wind velocity.
(appr. min. heat load requirements, see table below)
3. In order to prevent coil freezing, the 3-way valve must be positioned to let the full flow circulating through the
prime surface coil.
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, if these conditions cannot be met.
Draining of the coil(s) is not recommended as a normal method of freeze protection unless the coil(s) are
constructed from stainless steel or are of the cleanable type. For standard hot dip galvanized coils draining is
ONLY acceptable as an emergency method of freeze protection, since draining will lead to internal corrosion of the
coil. For this purpose an automatic drain valve and air vent needs to be installed to drain the coil(s) if flow stops or
the fluid temperature drops below 10°C when the ambient temperature is below freezing.
Ensure that all coils and/or coil sections (split coils/multi-circuiting) can drain individually.
Model Min. flow
l/s
Appr. min. Heat Load
(kW)
Standard Unit
HXI-42X 3 95
HXI-43X 3 143.
HXI-44X 5 189
HXI-54X 6 240
HX-Q54 12 270
HXI-56X 6 365
HXI-Q56X 12 415
HXI-64X 7 282
HXI-Q64X 14 315
HXI-66X 7 421
HXI-Q66X 14 468
Minimum Requirements for Water Flow and Heat Load
The "x" represents the variable numbers or characters in the model numbers.
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16

Draining of the coil is not recommended as a normal method of freeze protection. Frequent draining promotes
oxidation inside the coil tubes. Full draining of the heat exchanger coil is not guaranteed because of rising coil
circuiting on the finned discharge coil (optional) and the risk for coil freeze-up remains. The local BAC Balticare
representative should be consulted for guidelines on the installation of an emergency coil drain system.
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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 . C O . Z A
MAINTENANCE PROCEDURES
Checks and Adjustments
COLD WATER BASIN AND BASIN STRAINERS
The cold water basin should be inspected regularly. Any debris which may have accumulated in the basin or on the
strainers should be removed.
Quarterly, or more often if necessary, the entire cold water basin should be drained, cleaned and flushed with fresh
water to remove the silt and sediment which normally collects in the basin and under the wet deck surface during
operation.
If not removed periodically, this sediment can become corrosive and cause deterioration of the metallic basin
fittings.
When flushing the basin, the strainers should be left in place to prevent the sediment from re-entering the unit
system. After the basin has been flushed, the strainers should be removed, cleaned, and replaced before refilling
the basin with fresh water.
Caution
DO NOT USE ACID TO CLEAN THE STRAINERS
Remote Basin
The water level in the basin of equipment designed for remote basin operation is a function of the circulating water
flow rate, water outlet connection size, quantity and location, and outlet piping size and configuration. The remote
basin unit is supplied without a water make-up assembly and the basin operating level during remote basin
operation is not adjustable.
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HXI
5
5 Maintenance Procedures
5 Maintenance Procedures

Cold Water Basin and Basin Strainer
OPERATING LEVEL AND MAKE-UP
Before initial start up the straps, that prevent the float ball from moving during transport, as well as the protective
bag around this ball, need to be removed.
Fixation and wrapping of Float ball
As the water circulating through the unit is cooled, it collects in the cold water basin and passes through the
strainers into the system.
The operating water level is controlled by the make-up valve and should be maintained at the operating water level
shown in the table below.
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5 Maintenance Procedures
5 Maintenance Procedures

Model No. Operating Level (measured from the pan bottom)
(mm)
HXI-4XX 255
HXI-5XX
HXIQ-5XX 180
HXI-6XX
HXIQ-6XX 180
Cold Water Basin Operating Heights
The "x" represents the variable numbers or characters in the model numbers.
The operating water level in the cold water basin will vary somewhat with system thermal load (evaporation rate),
the bleed rate employed and the make-up water supply pressure. Because the typical winter load is less than the
summer load, the winter evaporation rate is frequently less than the summer evaporation rate. With this reduced
evaporation rate in winter, the water level in the cold water basin will increase unless the float is readjusted. The
operating water level should be checked monthly and float re-adjusted as necessary to maintain the recommended
operating level.
A float operated water make-up assembly is furnished as standard equipment on evaporative cooling equipment. It
is located inside the unit within easy reach from the access door.
The standard make-up assembly (see figure below) consists of a make-up valve connected to a float arm
assembly and actuated by a large diameter plastic float. The float is mounted on an all-thread rod which is held in
place by wing nuts. The operating water level in the cold water basin can be adjusted by repositioning the float and
all-thread rod using the wing nuts provided.
The make-up assembly should be inspected monthly and adjusted as necessary. The valve itself should be
inspected annually for leakage and the valve seat replaced if necessary. The make-up water supply pressure
should be maintained between 100 and 450 kPa for proper operation of the valve.
To make the initial basin water level setting, fill the sump with water until 2 cm above operating level. Adjust the
wing nuts of the float ball so, that the make-up valve is completely closed. Before starting the unit for the first time,
fill the sump till 1 cm below overflow level (push float ball under). Under normal load conditions this setting should
produce the correct operating level. At low load conditions the operating level will rise and needs to be adjusted.
The unit basin should be closely monitored and water level adjusted as necessary during the first 24 hours of
operation.
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5
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