Refrigerant Charge; Compressor; Condenser; Dehydrating Filter - Johnson Controls CWP Manual De Instalación Y Mantenimiento

Maintenance

9.3 Refrigerant charge

Do not inject refrigerant liquid into the LP
side of the circuit. Be very careful, and
charge the circuit properly. If the charge is
insufficient, the efficiency of the unit will be
lower than expected. In the worst of cases
the LP pressure switch may be activated, re-
sulting in the halting of the unit.
In the presence of an excess charge, the
condensing pressure will rise (in the worst
of cases, the HP pressure switch may be ac-
tivated, resulting in the stop of the equip-
ment), and the consumption will increase as
well.
It is strictly forbidden to use the compressor
as a vacuum pump to drain the plant.
Fill the refrigeration circuit after it has been drained
for maintenance purposes (leaks, replacement of the
compressor etc.). The amount of the charge is indi-
cated on the plate affixed to the unit.
Before refilling, it is important to drain and de-hy-
drate the circuit, thus obtaining a minimum abs. pres-
sure value of 50 Pa.
Inject the refrigerant fluid before removing the vacu-
um, then fill the circuit up to 90% of the total gas re-
quirement (in liquid form). The appliance must be
filled through the filling valve on the liquid line.
It is recommended to connect the refrigerant cylinder
to the filling valve on the liquid line, and to arrange it
in such a way as to inject only liquid refrigerant.
Then start the compressor and let the gas flow from
the cylinder, up until the liquid flow, which can be
observed through the sight glass, is limpid.

9.4 Compressor

Compressors are delivered with the necessary
charge of lubricating oil. During normal operation,
this charge is sufficient for the whole life of the unit,
providing that the efficiency of the refrigeration cir-
cuit is satisfactory and if it has not been overhauled.
If the compressor needs to be replaced (following a
mechanical failure or if burnt), contact one of Itelco-
Clima's Service Centers.
Compressors use polyester oil. During
maintenance operations on the compressor,
or if you have to open the refrigerant circuit
in any point, remember that this type of oil
is highly hygroscopic, and accordingly it is
important that it is not left exposed to the
weather for prolonged periods, as this
would require the replacement of the oil.
In a few cases, the polyester oil may be pre-
sent also in R22 units (a refrigerant that can
be used also in extra UE countries).

9.5 Condenser

Check the condenser water side for cleanliness at reg-
ular intervals. This may be accomplished by checking
water side pressure drop (refer to Section 9). Soiling
of the condenser results in increased condensing
pressure, which reduces efficiency and increases
current consumption and may cause the high pres-
sure switch to activate.
It is advisable to supply the condensers with antial-
gae and anti-line treated water
If soiled, the heat exchanger must be chemically
cleaned by Authorised service personnel.
For other types of service (special maintenance, heat
exchanger replacement, etc.), contact an Authorised
Service Centre).

9.6 Dehydrating filter

The refrigeration circuits are provided with dehydrat-
ing filters.
The filter clogging is marked by the presence of air
bubbles in the sight glass, or by the difference be-
tween the temperatures measured downstream from
and upstream of the filter. If, once the cartridge has
been cleaned, there are still some air bubbles, the
appliance has lost a part of the refrigerant charge in
one or more points, that must be identified and ser-
viced.

9.7 Sight glass

The sight glass is used for inspecting the refrigerant
flow and the humidity % of the refrigerant. The pres-
ence of bubbles indicates that the dehydrating filter
is clogged or the charge insufficient.
A colour indicator is positioned inside the sight
glass.
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