W.Tech RAA Series, Series TAA Installation And Maintenance Manual

W-Tech S.r.l.

Via Moglio, 18/2 - 40037 Sasso Marconi - (BO) Italy

T: [phone] F: [phone]

[e-mail] - www.w-tech.it
Reg. Imp. BO C/F - P.Iva: 03079111203 - Rea BO 490312 - Cap. Soc. 32.000

€ i.v.

Installation and maintenance manual

Closed circuit evaporative cooler

Axial type

Serie RAA

Pag 1

TABLE OF CONTENTS

1. MACHINERY DESCRIPTION 2

1.1 General safety use

1.2 General description 2

1.3 Primary Circuit. 2

1.4 Secondary Circuit 2

1.4.1 Water pumping system 2

1.4.2 Water distribution system 2

1.5 Air induction system 2

1.6 Casing and water collection basin. 3

2. DELIVERY AND HANDLING 4

2.1 Delivery Method 4

2.1.1 Lower body 4

2.1.2 Middle body (if any) 4

2.1.3 Upper body 4

2.2 Handling 4

3. INSTALLATION 5

3.1 Tower foundation and anchoring 5

3.2 Location conditions 6

3.3 Assembly of the bodies 7

3.4 Electrical connection 7

3.5 Other details for the installation 7

4. OPERATIONS TO BE CARRIED OUT BEFORE THE START UP 8

4.1 Cleaning 8

4.2 Inspection and checking 8

5. START UP 8

5.1 Secondary circuit 8

5.2 Primary circuit 8

6. OPERATING INSTRUCTIONS 8

6.1 Tower Performance 8

6.2 Control of water quality in the circuit 8

6.2.1 Fouling and blocking 8

6.2.1.1 Salt precipitation 8

6.2.1.2 Suspended solids 8

6.2.1.3 Biological growth 9

6.2.2 Corrosion 9

6.3 Electrical locking 9

6.4 Cold weather operation 9

7. GENERAL MAINTENANCE INSTRUCTIONS 10

7.1 In the water pumping system 10

7.1.1 Grid 10

7.1.2 Basin 10

7.1.3 Water make-up 10

7.1.4 Electric pump 10

7.1.5 Water distribution system 10

7.1.6 Coil 11

7.2 In the air induction system 11

7.2.1 Motors 11

7.2.2 Fans 11

7.3 Casing and water collection basin maintenance 11

7.4 Drift eliminator 11

8. PREVENTIVE MAINTENANCE SUMMARY CHART 12

9. TROUBLESHOOTING 13

Pag 2

1. GENERAL SAFETY RULES AND MACHINERY DESCRIPTION

1.1 General Safety use:

The content of this manual is to be considered as an integration to the general safety rules applied in your country, in the environment
you are working in and also to the rules to be followed by law. In case of conflict with any of the previously mentioned rules in place,
please contact our technical office for alternative procedures that will not create conflict.
Always remember that any operation with mechanical machinery could be dangerous and make sure all possible precautions are
followed before and during assembly & maintenance. SAFETY FIRST !

1.2 General description
Closed circuit cooling towers of the RAA series are counter-flow induced draught coolers with the fluid to be cooled (primary circuit)
circulating in a closed sealed loop.
The fluid to be cooled pass through a coil, externally sprayed continuously with water, pumped in an open circuit (secondary circuit)
from the collection water basin. The evaporation of part of this water removes most of the heat from the fluid in the primary circuit.
Evaporation is achieved thanks to a high quantity of air moved, by the use of axial fan(s) installed on top of the unit, counter-flow
against the water of the secondary circuit.
The closed circuit cooling tower is composed by the following elements:

Primary circuit:

• Coil

Secondary circuit:

• Water pumping system

• Water distribution system

Other:

• Air system

• Casing, water collection basin, air intake and louver panels.

• Drift eliminator

1.3 Primary circuit (coil)
Coil is made by high quality carbon steel bended and welded. A further process of hot dip galvanization assures the necessary
protection against external corrosion. Coil can be supplied on request in stainless steel both 304 and 316 grade.
During assembly the coil is tested in accordance to actual rules (PED). A further test is done before fitting the coil into the machine.
Different test procedures or witnessed tests are possible with extra costs.

1.4 Secondary circuit

1.4.1 Water pumping system

The exchange coil is sprayed with water collected from the basin of the unit and pumped by the use a centrifugal pump inside
a water distribution system. The motor of the pump is directly coupled on the bronze impeller and installed in a vertical
position facilitating inspection and maintenance. The water is then collected in the basin of the unit and ready to be pumped
again, after passing through a stainless steel filter/strainer installed in the bottom of the basin.

1.4.2 Water distribution system

Water is pumped in the top of the closed circuit cooler and distributed through a galvanised steel collector and polypropylene
(PP) pipe network. It could also be supplied in Stainless Steel with extra cost.
Spray nozzles (made by static fibreglass reinforced polypropylene) are screwed into the PP pipes and allow water to drop onto
the coil. Nozzles have a wide water passage, with minimum possibilities of clogging, breaking down or blocking. The design of
the nozzles is studied to allow the perfect water distribution (full cone) over the coil.
In case of clogging or breaking or just for simple maintenance, they can be dissembled from the PP pipes and easy cleaned or
replaced.
Make-up water, to replace depletion through evaporation or elimination to avoid scaling, is carried out automatically by
means of an intake valve installed in the basin.

1.5 Air system
Air is supplied in counter-flow to the water and is provided by axial fan(s) statically and dynamically balanced, installed at the top of
the cooling tower (induced draught).
The fan can be manufactured in different materials (PP, Aluminium, etc.) being placed inside the diffusers, which can also be
manufactured in different materials like painted galvanised steel (standard) or stainless steel. An arrow indicates the fan direction to
be used. In order to protect the fan from any external object and to prevent injuries a stainless steel safe-guard grid is installed in the
upper part of the diffuser.
The electric motor(s), totally sealed and self-ventilated, are provided standard with class F insulation, capable of withstanding a
temperature of 155°C. Electric motors are in accordance to the EU 690/2009 norm (if applicable). Running speed can vary in
accordance to each single machine project specification. Special motors can be fitted on demand. Motor(s) are mounted on a
galvanized steel support or plate, and installed inside the cooling tower, just below the fan.
In order to eliminate frictions, wearing or unnecessary maintenance (typical of an indirect coupling) the coupling between electric
motor(s) and fan(s) is direct.
Between the coil(s) and fan(s), a layer of drift eliminator made by PVC is provided.

Pag 3

1.6 Casing and water collection basin
The body of the unit is manufactured in “sendzimir” galvanised steel covered with 300 g/m

2

zinc layer. As a standard, a minimum 80µ
complete paint of epoxy-polyester layer is applied on each side of the panels. The application is done by electrostatic process,
completed by a further one hour stop in to the oven. This is giving a considerable resistance against water corrosion, ultraviolet rays
and other atmospheric elements.
This painting procedure is internally named W-COAT® and is given as standard protection on all products manufactured W-Tech.

The lower body of the casing forms the cold water basin. A minimum 2% slope is granted, in order to naturally flow water out of it. On
one side of the basin, a stainless steel anti cavitations suction filter is provided to protect the re-circulating pump that is installed
outside the basin.

In the water basin, the following standard connections are provided:

• Make up water with float valve

• Overflow

• Drainage

Other connections could be provided in accordance to the additional option element are possible to fit. For a quick review and not
limited to, we can mention:

• Electric heater (to avoid water freezing in the basin in winter time)

• Minimum water level switch for heaters (to protect electric heater to work uncovered by water)

• Minimum water level switch for pump (to protect re-circulating pump to work without the necessary water level)

Full list of options are listed in the technical sheet.