7
7 --- Maintenance
The Maintenance Programme below must be carried out by a
qualified technician, preferably working under a maintenance
contract.
Before any intervention on the unit or accessing the inner com-
ponents (removing the outer panels), always ensure the ma-
chine is switched off. If the rear panels are removed (coil com-
partment) wait for the fan(s) to come to a complete stop before
accessing the compartment; if the front panelsare removed, pay
special attention when working near the compressor upper part
and the discharge line: they are very hot; possibly wait for them
to cool. Be very careful when operating close to the finned coils,
as the fins are very sharp. Do not remove the fan protection grille
before electrically isolating the whole machine. Do not insert
foreign matter through the fan protection grille. After the main-
tenance interventions, always close the unit with the suitable
panels, fastened by the tightening system.
7.1 --- Spare parts
The use of original spare parts is recommended.
When placing an order refer to the ”Component List” enclosed
with the machine and quote the unit model no. and serial no.
7.2 --- Dismantling the unit
The machine has been designed and built to ensure continuous
operation.
The working life of some of the main components, such as the
fans and the compressors, depends on the maintenance that
they receive.
If the unit has to be dismantled, the job must be done by skilled
refrigeration technicians.
The refrigerant and the lubricating oil in the circuit must be dis-
posed of in conformity with the laws in force in your country.
Maintenance programme -- Monthly check
FANS
S
Check that the fan motor rotates freely without any abnormal noise, and ensure that the
bearings are not running hot.
S
Also check the current absorption.
CONDENSER AND AIR FILTER
S
Check the conditions of the filters (if they are supplied); if necessary clean them (including
the electrical panel ventilation filter).
S
Check the condenser coils and clean if necessary with compressed air or soft brushes.
CONTROL
S
Check that the control equipment, LEDs and display are operating correctly.
ELECTRICAL CIRCUIT
S
Check the electrical supply on all phases.
S
Ensure that all electrical connections are tight.
REFRIGERATION CIRCUIT
S
Check the condensing and the evaporating pressures (to be done by a refrigeration techni-
cian).
S
Check the compressor’s current absorption, the delivery temperature and possible unusual
noises.
S
Check the refrigerant charge by means of the sight glass.
S
Check that the safety devices operate correctly.
S
Check the correct operation of the thermostatic valve (superheating between 5
û
C
---
8
û
C).
S
Check that the oil level indicated by the compressor sight glass is higher than the min. value.
CHILLED WATER CIRCUIT
S
Ensure that there are no water leaks.
S
Bleed any air out of the hydraulic circuit using the bleed valves.
S
Verify that the water flow rate is correct.
S
Check the inlet --- outlet liquid temperature and pressure.
S
Check the correct operation of the three---way valve (Versions with free---cooling only).
S
Check if the system is charged with the specified glycol percentage and that no ice has
formed in the hydraulic circuit.
S
Check the evaporator cleanliness.
8 --- Options and Accessories
8.1 --- Pump set
The centrifugal pump units are direct driven, with close---
coupled motors and a single shaft; the induction motor has 2
poles with IP 54 protection and class F insulation.
The materials used for the pump main components are:
S
Pump body in plastic material PA 6.6 (cast iron in all high
pressure freecooling versions and on model 016 in the Chil-
ler high head pressure version and Superchiller standard
head pressure version);
S
Impeller in in plastic material PPO (stainless steel in all high
pressure freecooling versions and on model 016 in the Chil-
ler high head pressure version and Superchiller standard
head pressure version);
S
Stainless steel shaft;
S
Graphite impregnated ceramic mechanical seal (EPDM in
all high pressure freecooling versions and on model 016 in
the Chiller high head pressure version and Superchiller
standard head pressure version), suitable for the use of mix-
tures containing ethylene glycol.
The pump units have been chosen and sized to operate within
specific limits, namely:
S
Water / ethylene glycol mixtures up to 65% / 35% by weight;
S
Temperatures of the standard pumped fluid not lower than
4
°
C.
The hydrauliccircuitincludes, for each pump, a suction shut---off
valve and a delivery check valve if two pumps are installed, or
suction and delivery shut---off valves if a single pump isinstalled.
In the electrical panel there are automatic circuit breakers for
each pump; the microprocessor control manages the operating
rotation between the two pumps and start---up of the stand---by
pump if the primary pump fails.
For the technical features of the pumps and the hydraulic sche-
matic see Tab. 8, Fig. 12, Fig. 13, Fig. 14 and Fig. 15.
8.2 --- Water chiller with partial heat
recovery (20%)
This option enables the recovery of up to20% of the heatnormal-
ly rejected by the condensers. The system does not require any
adjustment and is made up of plate heat exchangers installed
on each circuit before the condenser. The exchangers are pro-
tected by a suitable anti---frost heater that operates when the sy-
stem is stopped. It is recommended that a safety valve be
installed in the hydrauliccircuittoavoid hazardsdue tooverpres-
sures, if there is no water flow through the recuperator.
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