W.Tech RAA Series Installation And Maintenance Manual - page 10
Pag 8
4. OPERATIONS TO BE CARRIED OUT BEFORE THE START UP
4.1
Cleaning
•
Make sure that the distribution system is clean and that the distribution nozzles are correctly positioned and free of any kind
of blockage.
•
Check if the water basin is completely clean, if not, clean it using water under pressure.
4.2
Inspection and checking
•
Check the anchoring of the tower, the fans and motors and make sure they are correctly and securely tightened.
•
Inspect the motors by sight, checking that they have been correctly installed.
•
Check the connections of the terminal boxes of the motors.
•
Make the fan turn for an instant, making sure that it turns easily and in the correct direction, without any unusual noise or
friction.
5. START UP
5.1
Secondary circuit
1.
Fill the cold water basin through the make-up water pipe or, better still, by means of flexible hose inserted provisionally into
the basin.
2.
Adjust the float arm of the make-up valve to ensure the level is maintained around 25 mm below the overflow level.
3.
Switch on the electric pump, checking its consumption. NEVER RUN THE PUMP WITHOUT WATER IN THE BASIN !!!
4.
The level of water inside the basin, with the electric pump working, has to be always above the suction level of the electric
pump and grid, in order to avoid cavitations.
This level can be checked from the manhole door, with the electric pump working and the fan(s) completely stopped.
5.
Once this regulation has been achieved, the fan(s) motor can begin to work and the cooling tower is prepared to start up.
5.2
Primary circuit
Once the operations of starting up on the secondary circuit have been performed, the primary circuit pump will be switched on,
checking its consumption.
VERY IMPORTANT !! THE TOWER MUST NEVER OPERATE WITHOUT HAVING THE FANGUARD AND THE ACCESS DOOR CORRECTLY FITTED. THE
FAN MUST BE STOPPED BEFORE THE OPERATIONS OF REMOVING AND REPLACING THESE ELEMENTS ARE CARRIED OUT.
6. OPERATING INSTRUCTIONS
6.1
Tower Performance
In order to obtain the appropriate performance from the cooling tower, care must be taken that the flow of both fluids are the design
ones, the secondary circuit water distribution is correct, and the different items in the distribution system must are clean and clear.
If a change in the secondary circuit water flow is required, it might be necessary to replace the nozzles, depending on the difference
between the design flow and the new required flow. Please consult W-TECH.
It is essential to keep the coil clean, as otherwise the cooling tower performance will be reduced. It is advisable to visually inspect the
coil periodically. In the same way, it must be considered that the tower does not govern heat load and, therefore, the fact that the
thermal range (difference between fluid in the primary circuit inlet and outlet temperature) is higher or lower than the design data, is
irrelevant.
6.2
Control of water quality in the circuits
Controlling the quality of the recirculating fluids is essential, not only for the cooling tower it self but also for all the elements that
make up the cooling circuits. We recommend that companies specialised in fluid conditioning and treatment should be consulted
about the fluids for each circuit. However, some general rules and instructions to be followed for correct circuit control are given
below:
This control must be aimed at preventing the elements in the circuits from:
1.
Fouling and blocking.
2.
Corrosion.
6.2.1
Fouling and blocking
This is caused by:
6.2.1.1 Salt precipitation (scaling), by their solubility product being exceeded.
The most common salts are:
•
Calcium Carbonate.
•
Calcium Sulphate.
•
Silicates.
The following conditions must be maintained in order to eliminate them: