Nature And Frequency Of The Scheduled Checks; Ii.10 Instructions For Maintenance; Ii.10.1 Routine Maintenance; Special Maintenance - Hitecsa EWMIM 117 Mode D'emploi

II.9 NATURE AND FREQUENCY OF THE
SCHEDULED CHECKS
DANGER!
Maintenance operations, even if for inspection
purposes only, must be carried out by skilled
technicians, qualified to work on air conditioning
and refrigeration products.
DANGER!
Always use the mains switch to isolate the unit
from the mains before carrying out any
maintenance work on the unit, even if it is for
inspection purposes only. Make sure that no one
supplies power to the machine accidentally; lock
the master switch in zero position.
In order to guarantee that the unit runs regularly and efficiently, it is
necessary to schedule an overall inspection at regular intervals to
prevent malfunctions which could damage the main machine
components.
Every 6 months
 Check the gas charge.
 Check that there are no gas leaks
 Check the power consumption of the unit
 Check the operation of the water differential pressure switch
 Air bleed from hydraulic system
 Check the contactors on the electric panel.
END OF SEASON with unit switched off
 Check that the air side heat exchanger is clean.
 Draining the water system
 Inspect and, if necessary, tighten the electrical contacts and
terminals.

II.10 INSTRUCTIONS FOR MAINTENANCE

DANGER!
Maintenance operations, even if for inspection
purposes only, must be carried out by skilled
technicians, qualified to work on air conditioning
and refrigeration products. Use suitable personal
protective equipment (gloves, goggles, etc).
DANGER!
Do not introduce pointed objects through the air
flow and intake grilles.
DANGER!
Always use the mains switch to isolate the unit
from the mains before carrying out any
maintenance work on the unit, even if it is for
inspection purposes only. Make sure that no one
supplies power to the machine accidentally; lock
the master switch in zero position.
DANGER!
In the event cooling or fan circuit component fail or
the refrigerant fluid charge drops, the upper part of
the compressor casing and the discharge line may
reach temperatures close to 150°C for brief periods
of time.

II.10.1 ROUTINE MAINTENANCE

II.10.1.1 Refrigerant circuit
Refrigerant charge check
With the unit off, fit a pressure gauge on the test point on the outlet side
and another on the test point on the inlet side. Start up the unit and
check both pressure readings once they have stabilised.
 Check for the absence of refrigerant fluid leaks
With the unit off, check the refrigerant circuit with a suitable leak
detector.
 Check that the air side heat exchanger is clean.
With the unit off, observe the air side heat exchanger and, as needed:
 remove any foreign bodies from the finned surface which may
obstruct air flow;
 remove built-up dust possibly vacuuming it;
 wash and brush, gently, with water and gentle brushing;
 let it air dry;
 keep condensation drain pipes free from any obstructions.
II.10.1.2 Hydraulic circuit
 Check the operation of the water differential pressure switch
SECTION II: INSTALLATION AND MAINTENANCE
With the unit running normally, slowly close the shut-off valve on the
unit water inlet pipe. If, during a test phase, the shut-off valve is
completely closed without the differential pressure valve triggering, stop
the unit immediately by pressing ON/OFF on the control panel and
replace the component.
 Bleed the air from the water system
Bleeding the air is facilitated by manual valves found inside the unit,
which are accessed by opening the panelling of the technical
compartment
 Pre-load pressure of the expansion tank
From the specific loading connection on the expansion tank, you can
verify the pre-load pressure (see Expansion tank technical data).
 Draining the water system
The system can be drained from the relief valve on the water inlet pipe.
Make sure the hydraulic circuit is completely emptied by opening all the
manual relief valves inside the unit.
SAFEGUARD THE ENVIRONMENT!
If the system has an antifreeze additive, it must not
be drained freely, because it causes pollution. It
should be collected for possible recycling. The
filling valve must not be opened in the presence of
glycol water.
II.10.1.3 Electrical circuit
The following checks are recommended on the electrical circuit:
 check the unit power consumption using a clip-on meter and
compare the reading with the values shown in the technical data table;
 with the unit disconnected from the power supply, check and inspect
electrical contacts and terminals for tightness.
II.10.2

SPECIAL MAINTENANCE

II.10.2.1 Component replacement instructions
If a unit requires repair, switch it off and recover the refrigerant fluid
from both the high and low-pressure sides and in the liquid line. This is
because, if the coolant is only drained from the high pressure side, the
compressor springs may close together, thereby preventing the
pressure from equalising. In this way, the low pressure part of the
casing and the inlet line could remain pressurised. In this case, if you
apply a brazing torch to one of the low-pressure components of the
system, the pressurised mixture of refrigerant and oil could blow out of
the circuit and ignite on contact with the brazing torch. To prevent this
risk it is important to make sure that the pressure on the high and low
pressure sides have actually been drained before desoldering.
II.10.2.2 Restoring the refrigerant load
Rapidly filling with refrigerant on the inlet side of a single-phase system
may prevent the compressor from starting or cause a breakage. The
best way to avoid this situation is to fill both high and low pressure sides
simultaneously. Topping up units with R410A refrigerant must be
carried out in the liquid phase, piping it from a cylinder so as not to alter
its composition.
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