W.Tech RAA Series Installation And Maintenance Manual - page 12
Pag 10
7. GENERAL MAINTENANCE INSTRUCTIONS
Due to the quality of these units, maintenance requirements are minimal. Nevertheless, they will be inspected fully on a monthly basis. In the
same way, the entire circuit should be cleaned every year.
It is advisable to carry out certain actions regularly in order to ensure that you achieve the service life and performance that these units have
been designed for
There are two basic areas to cover:
1.
Water recirculation system
2.
Air blowing system
7.1
In the water recirculation system
Due to the fact that the systems in which these products are based are related to evaporation, some salty concentrations, as well as
suspended solids are produced.
Therefore, some secondary water flow has to be removed, in order to prevent the concentrations in the coils. The drainage connection
will be used to do this.
The water conditions will be controlled continuously and automatically, by purging of dirty water and replacement with clean, addition
of bio dispersant agents and biocides, inhibitors to prevent lime scale from building up or the corrosion of the metallic parts of the
circuit. Several varieties are commercially available and the most suitable should be selected in consultation with specialised firms,
who have the knowledge of the water in the installations and the area. Be careful if any acid product is being used, due to the fact that
is not recommended the PH to be lower than 6.5. Another aspect to take into consideration is the fact that the products being used
have to be compatible with the kind of materials composing the cooling towers.
These units will be disinfected twice a year, at the beginning of spring and of autumn, as well as in the following circumstances:
•
Before putting into operation.
•
If they have been stopped for a long period of time.
•
When repairs have been carried out.
•
When routine inspection so indicates.
•
When the Sanitary Authorities so determines.
Disinfection will be carried out using authorised disinfectants; if chlorine is used, inject 5 p.p.m. of chlorine plus bio dispersants into
the basin and set the pumps running for five hours. The fans will be stopped.
Following this, all the water will be drained from the circuit and it will be cleaned thoroughly, adding water until the drain water
appears clean.
Finally, it will be filled with clean water and between 5 and 15 p.p.m. of chlorine will be added. The pumps will be allowed to run for 5
hours, with the fans stopped (check the chlorine level every hour).
The water conditions will be controlled continuously and automatically, by purging of dirty water and replacement with clean, addition
of bio dispersant agents and biocides, inhibitors to prevent lime scale from building up or the corrosion of the metallic parts of the
circuit.
The water will be drained out of the basin when the unit is not in use.
The maintenance functions to be carried out for the different elements are listed below.
7.1.1
Grid
This has to be cleaned monthly, or as frequently as the sediment presence requires.
7.1.2
Basin
This has to be cleaned and drained monthly, or as frequently as the sediment presence requires.
7.1.3
Water make-up
Float valve will be check monthly, as well as the water level in the basin, it always has to work above the grid and suction level
of the electric pump.
7.1.4
Electric pump
No special maintenance is needed. After around 10,000 working hours, bearings have to be checked, as well as the
mechanical locking.
If the tower is being stopped for a while, the removal of all water inside the pump is recommended, by means of the drainage
connection at the bottom.
VERY IMPORTANT !! WHEN RUNNING THE PUMP AFTER BEING STOPPED, ALWAYS TAKE INTO CONSIDERATION THAT THE PUMP MUST
BE CHARGED.
7.1.5
Water distribution system
This has to be checked monthly. To do so, some eliminator blocks have to be removed in order to inspect the inside part. The
fans have to be stopped and the electric pump will be switched on.
The nozzles, which are wide passage, with minimum possibilities of breaking down or blocking, allowing perfect water
distribution (full cone) over the coil. If by any chance they become clogged, they can be dissembled very easily.
This will mean that the grid is not clean, or the distribution pipes are dirty.
Therefore, the grid will be cleaned, the nozzles will be removed if necessary to do so, and the pump will be switched on, in
order to clean the pipes. If the nozzles have to be removed, when reinstalling in their place, be careful to put them in the
correct position, as shown in fig. 10.