Draining The System; Maintenance; Warnings On Maintenance; Hydraulic Circuit - AERMEC WSA Serie Manual Técnico De Instalación Y Mantenimiento

23.3 DRAINING THE SYSTEM

It is advisable to drain the system only
when the unit is going to remain inac-
tive for extended periods, or for main-
tenance operations that require drai-
ning.
- Before starting to drain the system,
turn "OFF" the main switch:
- Check that the water filling/topping
up tap is closed (NOT SUPPLIED).
NOTE
All the routine and extraordinary main-
tenance operations must be carried
out only by qualified personnel.
Before starting any cleaning or main-
tenance operation, it is advisable to
disconnect the unit from the power
supply.
24. 1 WARNINGS
ON MAINTENANCE
i Inspection, maintenance and pos-
sible repair operations must be
carried out only by an authorised
technician according to the law.
A deficient check/maintenance
operation may result in damage to
things and people.
Maintenance operations constitute a
necessary condition for the unit safe
and long-lasting operation, high relia-
bility and long life.
All the units are subject to wear along
time.
Maintenance operations allow:
- To keep the unit efficiency
- To reduce the speed of wear
- To collect information and data and
understand the unit efficiency status
to prevent possible failures.
It is therefore essential to carry out,
once a year, checks such as:

24. 1 . 1 HYDRAULIC CIRCUIT

- Water circuit filling
- Clean the water filters
- Check the flow switch
- Eliminate the air from the circuit
- Check that the water flow rate is
always constant.
34
- Open the drain tap and all the drain
valves of the system and the corre-
sponding terminals.
CAUTION
i
If the system uses glycol, this li-
quid should not be drained freely
because it is polluting. It must be
collected and, if possible, reused.
- Use of exchanger heaters.
In this case the heaters must al-
ways be powered for the entire win-

MAINTENANCE

24
- Check the hydraulic piping thermal
insulation state
- Check the glycol percentage, when
present.

24. 1 .2 ELECTRIC CIRCUIT

- Efficiency of safety devices
- Electrical power supply
- Electrical power consumption
- Electrical connections
- Check the conditions of electrical
wires and their insulators
- Check the compressor casing opera-
tion.

24. 1 .3 Cooling circuit

- Compressor conditions
- Check the working pressure
- Check the cooling circuit sealing, and
make sure that the pipes in it have
not suffered damages.
- Check the high pressure switch ope-
ration, in case of failure, replace the
switches
- Check the filter-drier fouling state. If
there is scale in it, replace it.

24. 1 .4 MECHANICAL CONTROLS

- Check that screws, compressors and
the electronic box of the unit external
panelling are properly tightened. If
they are poorly tightened, they pro-
duce abnormal noise and vibrations
- Check the structure conditions.
If necessary, treat oxidised parts
with paints suitable for eliminating or
reducing oxidation.
i
It is advisable to keep a machine
booklet (not supplied, but provided
by the user), in order to keep trace
of the operations carried out on
the unit. In this way, it will be easier
ter period (machine in standby).
Circuit with glycol
- The operation with glycol water, with
a glycol percentage chosen on the
basis of the minimum outside tem-
perature envisaged. In this case due
account must be taken of the diffe-
rent yields and input requirements
of the chiller, the scaling of the pum-
ps and terminal yields.
to organise the operations proper-
ly and facilitate failure prevention
and troubleshooting in the machi-
ne.
In the booklet, write down date,
type of operation carried out (rou-
tine maintenance, inspection or
repair), description of the opera-
tion, measures taken...
24.2 EXTRAORDINARY
MAINTENANCE
WSA chillers are charged with gas
R134a and tested in the factory. In nor-
mal conditions, no Technical Assistance
Service operation is needed for the re-
frigerant gas check. Except for version
E, which is sold only with the charging
capacity. Along time, however, small
leaks from the joints may be genera-
ted. Due to these leaks, the refrigerant
comes out and the circuit is drained,
causing the unit malfunction. In these
cases, the refrigerant leakage points
are found and repaired, and the cooling
circuit is recharged, operating in com-
pliance with Law 28 December 1993
no. 549 (Italy).
i
CAUTION
It is forbidden to CHARGE the coo-
ling circuits with a refrigerant dif-
ferent from the one indicated. If a
different refrigerant gas is used, the
compressor may result seriously
damaged.