Carrier DB-S Series User guide

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DB-S
DB-S
UUSSEE
&& MMAAIINNTTEENNAANNCCEE IINNSSTTRRUUCCTTIIOONNSS
UUSSEE&&MMAAIINNTTEENNAANNCCEEIINNSSTTRRUUCCTTIIOONNSS
BBEEDDIIEENNUUNNGGSSAANNLLEEIITTUUNNGG
BBEEDDIIEENNUUNNGGSSAANNLLEEIITTUUNNGG
IINNSSTTRRUUCCTTIIOONNSS
DD''UUSSAAGGEE EETT EENNTTRREETTIIEENN
IINNSSTTRRUUCCTTIIOONNSSDD''UUSSAAGGEEEETTEENNTTRREETTIIEENN
MMAANNUUAALLEE
UUSSOO EE MMAANNUUTTEENNZZIIOONNEE
MMAANNUUAALLEEUUSSOOEEMMAANNUUTTEENNZZIIOONNEE

2
SERVICE SHEET - SERVICEBLATT - FICHE DE SERVICE - FOGLIO SERVIZIO
DATE - DATUM OPERATION - MASSNAHME SERVICE FIRM - SERVICEFIRMA
SIGNATURE - UNTERSCHRIFT
DATE - DATA OPERATION - OPERAZIONE ETS DE SERVICE - DITTA ASSISTENZA SIGNATURE - FIRMA

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LLiisstt
ooff ccoonntteennttss
LLiissttooffccoonntteennttss
1. Description of the unit ....................................................................page 4
1.1 How the unit works ............................................................................page 4
1.2 Safety devices and safety measures ................................................page 5
1.3 Synopsis of signs ..............................................................................page 5
1.4 Residual risks ....................................................................................page 7
2. Technical features of the unit ........................................................page 7
3. Intended uses ..................................................................................page 7
3.1 Dangers deriving from using the unit for purposes
other than those it is designed for ....................................................page 7
4. Positioning the unit ........................................................................page 8
5. Installation........................................................................................page 9
5.1 Signs..................................................................................................page 9
5.2 Dimensions of unit and packing ........................................................page 9
5.3 Commissioning ..................................................................................page 10
5.4 Area surrounding the unit to be kept clear ........................................page 11
6. Assembly and preparation for commissioning ............................page 11
6.1 Cleaning the unit................................................................................page 13
6.2 Connecting the unit to external power sources ................................page 13
6.2.1 Power mains connection ..................................................................page 13
6.2.2 Water mains connection ....................................................................page 14
6.3 Checks, adjustments and settings ....................................................page 14
7. Placing into service of the unit ......................................................page 15
7.1 Electrical controls ..............................................................................page 15
7.1.1 Control panel ....................................................................................page 15
7.1.2 Remote panel ....................................................................................page 16
8. How to operate the unit ..................................................................page 17
8.1 Description of the unit’s work cycle ..................................................page 17
8.2 Operational features of the defrosting timer ......................................page 17
8.3 Diagram of the unit’s electrical system ..............................................page 17
9. Maintenance and repairs ................................................................page 18
9.1 General maintenance operations ......................................................page 18
9.2 Special maintenance operations ......................................................page 18
9.3 Operations to be carried out by qualified personnel
or by the Manufacturer ......................................................................page 18
9.4 Troubleshooting guide ......................................................................page 18
9.5 Electronic controller alarms ..............................................................page 20
9.6 Emergency system ............................................................................page 20
9.7 Parts subject to wear and spares ......................................................page 21
10. Disposal of packing material..........................................................page 21
11. Dismalting the unit ..........................................................................page 21

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Thank you for choosing a uniblock product.
Please read this booklet carefully - it has been specially designed to provide advi-
ce and information on how to install, use and maintain the unit correctly, so as to
use it to the best of its capacities.
The term CAUTION is used to indicate situations that may cause damage to
the unit. These appear in italics.
The term WARNING is used to indicate situations that might endanger the
safety of operators. These appear in italics and, in some case, also in bold.
All measures indicated in this catalogue are stated in millimetres
The main features of these units are that they are manufactured in two main parts:
1. a condenser unit, to be installed external to the cell
2. an evaporator unit, to be istalled internal to the cell
3. an electrical control panel, located on the condenser unit and a remote control
panel.
This feature permits to overcome the problems due to the lack of space external
to the cell which prevent the assembling unit; in fact the two parts can be istalled
with a distance between them.
1.1 How the unit works DB-S uniblock refrigerating units operate by means of a scroll a/c mains powered
refrigerating compressor (single-phase or three-phase), using HFC refrigerating
liquids.
The refrigerating liquid flowing through the evaporator exchange battery cools the
room in which the battery is located. By flowing through the condenser exchange
battery, it then regains its cooling capacity. Thus the cycle starts again. An auto-
matic defrosting cycle is also pre-set to take place automatically, although it can
be cancelled by the user by resetting the timer that governs its cyclic programme.
Defrosting occurs by means of an electric resistor system.
11..
DDEESSCCRRIIPPTTIIOONN OOFF UUNNIITT
11..
DDEESSCCRRIIPPTTIIOONN OOFF UUNNIITT
1
3
2
fig.1
LEGEND
LEGEND

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1.2 Safety devices and safety measures The following mechanical safety devices are supplied by the manufacturer (fig. 2):
1. Fixed side guards of the evaporator and condenser units: these are fixed to the
metal casing with locking screws
2. Electric fan fixed external guards on the evaporator: these are fixed with self-
locking screws.
The following electrical safety devices are supplied by the manufacturer:
1. Compressor thermal relay with manual resetting: protects the compressor
against excessive current absorption.
2. High pressure switch with automatic resetting: protects against excessively
high pressure.
3. Thermistors with automatic resetting: protects the motor against
overheating.(only for models with semihermetic compressors)
WARNING
Safety devices have been designed by the manufacturer to ensure the safety of
operators while carrying out their work
1.3 Synopsis of labels The following caution and warning signs have been placed on the unit by the
manufacturer:
INDICATION:
TYPE OF REFRIGERATING LIQUID
2
1
1
11
2
11
2
Ø*
Ø**
R 404 A
3ETA237
SCARICO CONDENSA
CONDENSATE DRAIN LINE
ECOULEMENT DE CONDENSATION
KONDENSATABLAßROHR
DESAGÜE CONDENSACíON

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WARNING:
CAUTION!
hot and/or cold parts
CAUTION:
Direction of rotation
Volt Phases Hz
COLLEGAMENTO UNIBLOCK
UNIT ELECTRICAL CONNECTION
CONNEXION DE L'UNITE'
ELE KTRISCH. ANSCHLU SS
CONEXION DE L'UNIDAD
COLLEGARE QUESTO CAVO AD UN INTERRUTTORE MAGNETOTERMICO. MAI
DIRETTAMENTE ALLA LINEA PRINCIPALE.
CONNECTION SHOULD ALWAYS BE MADE FROM A FUSED ISOLATOR. NEVER CONNECT
THE CABLE TO THE MAINS SUPPLY LINE DIRECTLY
LA CONNEXION DOIT ETRE EFFECTUEE AU MOYEN D'UN INTERRUPTEUR MAGNETO-
THERMIQUE. JAMAIS CONNECTER LE CABLE A LA LIGNE PRINCIPALE DIRECTEMENT
DER ANSCHLUSS DES KABELS SOLL DURCH EINEN THERMOMAGNETSCHALTER
FOLGEN. KEIN DIREKTER ANSCHLUSS DER HAUPTSPEISELEITUNG
CONNECTAR EL CABLE A UN INTERRUPTOR MAGNETOTERMICO. Y NUNCA
A LA LINEA DIRECTAMENTE
ATTENZIONE! PERICOLO
GIALLO/VERDE JAUNE/VERT
GELB/GRUEN YELLOW/GREEN
L2
L1
L3
V.400/3~/50 Hz.

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The specific technical features of each DB-S model are indicated on the data
plate attached to the unit (fig. 3).
The DB-S range includes air condensed refrigerating units designed and manufactu-
red to operate automatically. Using the machine for any purposes other than those
envisaged represents an anomaly and may seriously endanger people’s safety.
3.1 Dangers deriving from using the The unit is not designed to operate in premises where explosives are stored.
unit for purposes other than Therefore, it is categorically forbidden to use it in locations where any risk of
those it is designed for explosion exists.
Should the user wish to use the unit for any purposes or in any fields other than
those intended (see ch. 8, section 8.2 of this manual), or wish to modify the unit
in any way, he should consult the manufacturer/distributor about any contraindi-
cations or dangers that may derive from the incorrect use of the unit.
1.4
1.4 RESIDUAL RESIDUAL RISKS RISKS
22..
22..
TTEECCHHNNIICCAALL
FFEEAATTUURREESS OOFF TTHHEE UUNNIITT
TTEECCHHNNIICCAALL
FFEEAATTUURREESS OOFF TTHHEE UUNNIITT
fig.3
Mod.
Mod.
Matricola
Serial Number
Tensione
Voltage
Assorb. Marcia
Run Absorption
Refrigerante
Refrigerant
Massa C
Mass C
AKw
Kg
Via Martin L. King, nr. 30
46020 PEGOGNAGA
(Mantova) - Italy
ZANOTTI
SS..pp..AA..
Modello
Model
Potenza compressore
Compressor power
A
Assorb. Max
Max Absor.
Kw
Schemi
Diagr.
1) Anno di costruzione
2) Codice unità "CARRIER"
3) Numero matricola
4) Tensione
5) Assorbimento Marcia (Macchina)
6) Assorbimento massimo
7) Assorbimento di spunto (Macchina all' avviamento)
8) Potenza nominale compressore
9) Refrigerante : Tipo ; Quantità
10) Massa macchina
11) Numero schema elettrico (Progetto)
Carrier Refrigeration AB
A
Ass. Spunto
Start. Abs.
Kg Massa E
Mass E Kg
33..
33..
IINNTTEENNDDEEDD
UUSSEESS
IINNTTEENNDDEEDD
UUSSEESS
1) Year of manufacture
2) CARRIER unit code
3) Serial number
4) Voltage
5) Operating current
6) Maximum current
7) Starting current
8) Compressor’s nominal power
9) Refrigerating liquid Type; Quantity
10) Mass of the unit
11) Electric diagram (Project) number
Below we list all the situations - from the delivery of the unit to its demolition
- in which the user will need to exercise caution in order to avoid damage to
persons.
CHAPTER 4 - Positioning the unit
Maximum caution should be used in ensuring that no one passes through
the area while the suspended load is being handled, in order to avoid any
chance of damage to persons.
CHAPTER 9 - Maintenance
Condenser and evaporator groups’ fins: any maintenance operations must
be carried out using personal protection devices (e.g. gloves) in order to
avoid any chance of damage to hands.

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The unit can be moved with lifting and transport devices. (Fig.4)
WARNING
Take the utmost care in ensuring no one passes through the platform truck’s
manoeuvring area, so as to avoid any risk to personnel while the load is
being handled.
The unit is shipped packed in a wooden case or in a wooden crate: the
movement has to be done securing the packaging with a sling in an appro-
priate way.
Take special care in ensuring that the packing crate containing the unit is not lif-
ted too quickly to avoid oscillations which may damage or break the unit.
44..
44..
PPOOSSIITTIIOONNIINNGG
TTHHEE UUNNIITT
PPOOSSIITTIIOONNIINNGG
TTHHEE UUNNIITT
fig.4

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5.1 Signs The Manufacturer has envisaged the posting of the following caution and warning signs:
Caution: Low /high temperature
Switch off before handling the unit
Caution: danger
5.2 Dimensions of unit and packing DB-S range units come in different sizes, as indicated in the following diagrams (fig. 5-6)
DB235-S
MDB335NS02F
DB335-340 S
55..
IINNSSTTAALLLLAATTIIOONN
55..
IINNSSTTAALLLLAATTIIOONN
fig.5
Ø 1/2''Gas
1170
1220
50
Ø*
Ø**
520
690
1104 504
N
M
Ø12*
Ø**
Ø 1/2''Gas
E
F
G
C
D
* Delivery pipe
** Suction pipe
Cod. ***
MDB235 10 22
BDB235N
10 28
BDB235T 12 35
Cod. **
MDB335 28
BDB335 35
MDB340 28
BDB340 42
MOD.
MDB235NS02F
MDB235TS02F
BDB235NS02F
BDB235TS02F
Mod. A B C D E F G H I L M N
DB335-S 600 505 520 690 1570 1690 120 1158 1104 54 1254 504
DB340-S 620 545 520 700 1720 1840 120 1158 1104 54 1254 504
Ø12*
Ø**
Ø 1/2''Gas
1570
1690
120
520
690
1104 504
* Delivery pipe
** Suction pipe

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PACKING
DB235-S
DB335-S - DB340-S
5.3 Commissioning In order to achieve optimum performance, the unit must be:
a) Place the cell in a well ventilated room, away from heat sources (fig. 8)
b) Check that the unit has adequate aspirating and extracting power.
c) Ensure that the unit is in a horizontal position, so that condensation water can
easily be drained.
1410
840
Mass 98 Kg
Mod. ABCDEF Kg
MDB335NS02F 670 1350 810 830 1840 750 CU=89; EU=56
MDB335TS02F-BDB335NS02F-BDB335TS02F 670 1520 1360 830 1840 750 CU=114; EU=56
DB340 N/T 670 1520 1360 830 1990 780 CU=114; EU=63
solution 3
installation in a cell with
more than one unit
fig. 9
=
===
cell door
(heat source)
solution 1
cell door
(heat source)
cell door
(heat source)
solution 2
DE
EU CU

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5.4 Area surrounding the unit In order to allow it to work properly and to facilitate its maintenance in safety con-
to be kept clear ditions, the unit should be installed so that the minimum spatial requirements (for
opening the unit) are provided.
Ensure that no damage has occurred to the unit or the equipment it contains during
transportation, particularly to the components fixed to the electric control panel door
and to the refrigerating system pipes. Install the group in the cell (as indicated in the
diagram below) taking special care to the level of the unit (fig.10) and to the assembly
of the remote control panel.(fig.11)
Remote control panel installation
Unscrew the lateral fixings to remove the remote control panel cover plate
(fig. 11.1). Fix the base plate in the desired position using the pre-drilled holes
and making sure it is level (fig. 11.2).
Replace the cover plate by performing the operation indicated at fig. 11.1 in reverse.
Adjust the cable connection between the control panel and the unit, making
sure it does not interfere with existing cable connections.
Connect the condensation water drain located in the lower section of the conden-
ser to the evaporator, proceeding as indicated in the diagram below (fig. 12).
Special care must be taken in carrying out this operation in order to avoid any
blockage caused by ice formation.
The connection should be made using a plastic tube (1) of adequate diameter, not
smaller than that of the unit’s outlet; and a U-bend should be created in the lower part
so as to prevent warm air from entering the cell through the drainage pipe.
If the unit is installed in the open air where temperatures can drop below 0°C, it is
advisable to lag the tube with insulating material so as to prevent water from freezing
in the U-bend, which would prevent the normal draining of condensation water.
66..
AASSSSEEMMBBLLYY AANNDD PPRREEPPAARRAATTIIOONN PPRRIIOORR TTOO CCOOMMMMIISSSSIIOONNIINNGG
66..
AASSSSEEMMBBLLYY AANNDD PPRREEPPAARRAATTIIOONN PPRRIIOORR TTOO CCOOMMMMIISSSSIIOONNIINNGG
fig.10
260
Ø 12 n°4
A
> 200
Mod. A B
DB235-S
540 965
DB235-S 540 1370
DB340-S
545 1520
fig.11
fig.11.1 fig.11.2

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a) Connect the evaporator and the condenser with a piping adapted according to
the enclosed diagrams and tables (Fig.12)
FLOOR PLANE
FLOOR PLANE
FLOOR PLANE
fig.12 fig.12.a
fig.12.b
2
1
2
1
1.Drain pipe
2.Syphon
fig.12.c
2
1
-Section of suction
line in an installation
having the compres-
sor sited underneath
heevaporator
Put the heater* in the
drain pipe without fol-
ding (DB models).
Insulate the whole
suction line
Put the heater* in the
drain pipe without fol-
ding (DB models).
Put the heater* in the
drain pipe without fol-
ding (DB models).
Insulate the whole
suction line
Insulate the whole
suction line
* Discharge resistance only in low
temperature DB units
* Discharge resistance only in low
temperature DB units
* Discharge resistance only in low
temperature DB units
-First section of the suction
line in an installation
having the compressor
sited above the evapora-
tor (difference of level
less than 3 mt)
-First section of the
suction line in an
installation having
the compressor
sited above the
evaporator (diffe-
rence of level
more than 3 mt).

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b) Connect the circuitry between the evaporator and the condenser using the seriali-
zed terminal boards which are in the electronic panel and inside the evaporator.
6.1 Cleaning the unit Carefully clean the unit with detergents or degreasing substances, removing dust,
dirt and any foreign matter that may have deposited on it during transportation.
CAUTION! Do not use solvents
6.2 Connecting the unit to external 6.2.1 Power mains connection
energy sources Before making the electrical connection, ensure that the voltage and frequency of
the mains supply are as indicated on the unit’s serial plate and that the power
supply is within +/- 10% of nominal value.
Having conducted a preliminary inspection of the elements of the panel, make the
electrical connection. Connection to the mains supply must be made through a
magnetothermal differential switch.
Safety devices should be installed on the power supply line taking into account the
current absorption indicated on the plate.
When a cell contains more than one unit, each should be fitted with its own
magnetothermal differential switch.
Now connect the unit paying attention to the colour of the wires that make up the
power supply cable:
a) 110V-230V/1~/50-60 Hz 3 wires Blue = neutral
Yellow/Green = earth
Brown = phase
b) 230V/3~/50-60 Hz 4 wires Blue = phase
Yellow/green = earth
Brown = phase
Black = phase
c) 400V/3N~/50-60 Hz 5 wires Blue = neutral
Yellow/Green = earth
Brown = phase
Black = phase
Black = phase
It is necessary to observe the exact phase sequence, as all machines are equip-
ped with an electronic control device, placed on the electric panel or in the com-
pressor junction box, which prevents the compressor from switching on if the
exact phase sequence is not observed.
We advise the use of a microswitch on the room door which, when opening,
automatically:
- turns room light ON, stops evaporator fan and compressor
- overrides temperature alarm (for abt. one hour after door closing).
If a door microswitch, room light and door heater are required, proceed as follows:
Door microswitch connection:
Remove the electric bridge between terminals 19 and 20 on the electronic control
panel and connect there door microswitch cable according with this condition:
contact closed/ door closed.
Room lamp connection:
It has to be done between the fuse-holder terminal FL and the neutral terminal N5
The room lamp must be 230 Volt - 100 Watt.
Door heater connection:
Door heater is to be connected between the fuse-holder terminal FEP and the
neutral terminal N4. The heater is marked by the letters EP.
The output voltage is 230 Volt.

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CAUTION
Magnetothermal safety switches should be used to protect the main power sup-
ply line from power surges.
Only qualified personnel is authorised to replace the safety thermal relays fitted
on motors.
Only qualified personnel must be authorised to make electrical connections.
All models DB-S are supplied with remote control panel.
6.2.2 Connection to the
The water condenser must be connected to the water mains following the indications
water mains (water condenser) on the plates next to the tubes, which are marked IN (ENTRATA) and OUT (USCI-
TA). The diameter of the pipes used to make the connection must not be smaller
than the unit’s outlet tubes. Pressure in the water circuit must be at least 1 bar.
6.3 Checks, adjustments and settings Before switching the machine on, ensure that:
- locking screws are fixed tight
- electrical connections have been made correctly
When the unit is opened, check that:
- no tools have been left inside
- assembly has been correctly performed
- there are no gas leaks
- panels have been correctly fixed.

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Before placing into service the unit it is necessary to preheat.
To do this proceed as follows:
a) Switch on the unit with the mains switch.
b) Leave the unit in this position for at least 3 hours
c) After 3 hours,to start the unit it is necessary to press the key on/off on the
remote control panel.
N.B.: If the unit is stopped with the main switch for more than 3 hours in winter or
more then 6 hours in summer, it is necessary to repeat the preheating.
CAUTION
24 hours after start-up, check the evaporator. If ice has formed on it, reduce
the interval between defrosting cycles. For low temperature units this check
should be performed once a week during the first month of operation.
7.1 Electrical controls 7.1.1 Electrical panel
77..
PPLLAACCIINNGG IINNTTOO SSEERRVVIICCEE OOFF TTHHEE UUNNIITT
77..
PPLLAACCIINNGG IINNTTOO SSEERRVVIICCEE OOFF TTHHEE UUNNIITT
Mains switch
I ON
fig.14

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7.1.2 Remote panel
1) Compressor LED (GREEN):
LIT: the compressor is running.The unit is cooling.
FLASHING: the compressor is a delayed start mode.
OFF: the compressor is OFF. The required room temperature has been reached
.
2) Evaporator fan LED (GREEN):
LIT: Evaporator fan is running.
FLASHING: the evaporator fan is in a delayed start mode.
OFF: Evaporator fan is off.Unit in Defrost mode.
3) Defrost LED (YELLOW):
LIT: automatic or manual defrost in progress.
4) Alarm LED (RED):
LIT: Alarm mode: malfunctioning of a sensor, or intervention of pressure-stat
or room temperature outside preset limits.
OFF: Unit working normally.
5) DISPLAY: When the machine is not in operation, the label “OFF” and the cell
temperature are intermittently displayed one after the other on the digital display.
When the machine is in operation, during the normal working cycle, the display
indicates the cell temperature. Parameters being set will be displayed during
programming. A "Fault Code" will be displayed during alarm mode.
6) “SET” KEY. Permits entry of room temperature requirements.
7) “DOWN” KEY. Key to decrease data values.
8) “MAN.DEFR./UP” KEY. Key to increase data values.
Press for 8 seconds at least to initiate manual defrost as well.
9) Key “T.A.A.” Key to mute audible alarm.
This alarm is not fitted as standard to the unit but can be added by the client.
To connect use the free terminals 1 & 2 (volt free) on the internal electronic
panel. Terminal 2 should have a live feed brought to it.
10) “ON/OFF” KEY.Main switch.
11) “LAMP” KEY.Push to turn room lamp ON/OFF.A red LED lights when lamp is
ON.
11
22
33
44
55991100
6677881111

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8.1 Description of the unit’s Uniblock DB-S refrigerating units operate through a scroll refrigerating compres-
work cycle sor, powered by mains a/c supply (single phase or three phase) and use HFC
refrigerating liquids.
The refrigerating liquids, flowing through the evaporator exchange battery cool
the room that contains the battery. Then, flowing through the condenser exchan-
ge battery, it regains its cooling capacity and the cycle starts again.
A pre-set automatic defrosting phase is also envisaged, although the user can
modify it if he so wishes. The frequency of the cycle is controlled by a timer.
Defrosting takes place by means of an electrical resistance circuit.
8.2 Room temperature setting After placing into service the unit (paragraph 7) it is possible to adjust the room
temperature set-point.
CAUTION:
medium temperature setting range: +10° - 5°C
low temperature setting range: -15 - 25°C
Cell temperature programming:
Press key (10) to turn ON unit.The actual room temperature will be shown on the
display (5).In this condition the unit is ready for programming.It is necessary the-
refore to set the required room temperature bearing in mind the limits of the
range which the unit is able to operate.
Press the SET (6) key (the yellow LED will light).The last set temperature will be
displayed on the display screen (5) which showes the set value.
Press the set key (6): the yellow led will light for one second and the display (5)
will start flashing a few seconds later, indicating the set temperature. If you wish
to change the setting, use the following keys:
(8) to raise set temperature
(7) to lower set temperature
Once the required setting is displayed, press the set key (6) to confirm.
The unit is now fully operational and no other programming is required. The refri-
gerating cycle is fully automatic according to factory-set parameters, that can
eventually be modified by authorised personnel only.
8.3 Diagram of the unit’s Units in the DB-S range feature a special electrical system, a diagram of which is
electrical system attached to this manual.
88..
HHOOWW TTOO OOPPEERRAATTEE TTHHEE UUNNIITT
88..
HHOOWW TTOO OOPPEERRAATTEE TTHHEE UUNNIITT

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Adequate maintenance is an important factor to ensure the long life and optimum
performance of the unit and the safety conditions required by the Manufacturer.
9.1 General maintenance It is essential to clean the condenser which is located in the lower part of the
operations compressor unit (externally to the cell) in an easily accessible position.
The condenser is used to cool the refrigerating gas and it will work more effecti-
vely if it is kept free of dust.
The unit can be cleaned by simply using a dry brush and reaching deep between
the condenser’s fins or, better still, by using an air jet and blowing from the inside
out. This operation must be carried out while the unit is switched off.
If there are traces of oil on the condenser, check where they come from and,
having repaired the leak, clean using a detergent such as alcohol or petrol.
WARNING: To avoid cutting your hands, use protective gloves.
9.2 Special maintenance operations Periodically check the wear of electrical contacts and remote control switches and
replace if necessary.
9.3 Operations to be carried out Below is a list of maintenance operations that require specific technical compe-
by qualified personnel or by tencies and must therefore be carried out by qualified personnel or by the
the Manufacturer Manufacturer.
The User must on no account:
- replace electrical components
- tamper with the electric system
- make repairs on mechanical parts
- tamper with the refrigerating system
- tamper with the control panel
- tamper with safety and protection devices
9.4 Troubleshooting guide Technical problems that may occur during the operation of the machine:
1. In case of malfunction of the system, check the refrigerating gas through the flow
indicator located on all units fitted with a thermostat (this must be checked when the
unit is operating and the cell temperature is close to the required temperature).
Normally the indicator is clear, while, in the absence of gas, gas bubbles will appear.
2. If the compressor or fan stop, check the following:
- whether the safety fuses of the main and auxiliary circuit have been blown, in
which case they should be replaced, after checking the suitability of the mains
tension and ensuring that phase polarity is correct.
- if the compressor unit has stopped working (the indicator light on the panel is
on) it is necessary to reset the thermal relay manually, having first identified the
causes of the malfunction.
3. In case of unit malfunction check the following:
- that the evaporator is not frosted over. If it is, immediately defrost the evaporator
completely, by adjusting the timer (located inside the electric control panel) and star-
ting the defrosting cycle manually. Once the defrosting cycle is completed, check if
any ice is left on the evaporator, then repeat the operation described above. Shorter
time intervals between defrosting cycles should be set to reduce ice formation.
CAUTION:
On no account should sharp or pointed metal instruments, or hot water be used
to remove any blocks of ice that might have formed in the evaporator.
99..
MMAAIINNTTEENNAANNCCEE AANNDD RREEPPAAIIRRSS
99..
MMAAIINNTTEENNAANNCCEE AANNDD RREEPPAAIIRRSS

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4. Inadequate performance of the unit:
If the unit’s performance is not adequate, and no technical causes or anomalies can
be identified, it is necessary to check that the cell doors are perfectly sealed, that
there are no leaks from the cell, that no foodstuffs or non frozen liquids have been
inserted in the low temperature cell and that no ice has formed on the evaporator.
It is therefore advisable to locate the unit away from doors, especially if these are
opened several times a day.
WARNING:
It absolutely forbidden to remove the safety devices provided by the anufacturer
to protect operators while the machine is in operation.
5. Other malfunctions may be due to the triggering of the following electrical
safety devices:
a) Fan thermal protection (incorporated in the motor) - automatic resetting. This
device is designed to safeguard electrical fans against excessive current absorp-
tion due to:
- overheating
- lack of one phase (only for three phase models)
- dirt in the condenser
- ice in the evaporator
b) Discharge Line Thermostat
Protects the compressor against elevated discharge temperatures which can
typically occur in certain conditions such as low gas charge or failed condenser
fan.
c) High pressure switch - manual resetting
It is designed to protect the compressor from excessive pressure, which cause
the pressure switch to be triggered too often, deriving from:
- dirt in the condenser
- condenser fans not working
- excessive temperature in the room where the system is located
- use of the system in unsuitable conditions or with inappropriate products.
To reset press the button on the pressure switch.
d) Low pressure switch - automatic resetting
It is generally used to stop the unit working in pump-down mode.
The triggering of the pressure switch can also indicate excessively low pressure
in relation to the set points, due to one of the following causes:
- lack of gas due to the breakage of a pipe or to loose hub
- clogged up filters
- solenoid valve failure
- ice in the evaporator
The minimum and maximum temperature pressure switches and the oil pressure
switch are located inside the motor casing. Before resetting, disconnect from mains.
e) Thermistors - automatic resetting
These are inserted in the compressor’s coil to protect the motor from overheating
(see electrical diagram)
f) Minimum and maximum tension electronic relay (Monitor) - automatic reset
(where applicable). It is used to protect the unit against anomalies in the power
supply (+/-12% of nominal value). The unit starts with a delay of 8 minutes, indi-
cated on the panel by a LED.
The main factors that cause the triggering of the device are anomalies in the
power supply (for further information see attachment)
g) Phase sequencing relay
Is an electronic device which prevents the compressor from starting if the phases
are not connected in the correct sequence. This device can be found either in the
electrical panel or integtrated in the compressor protection module.
h) Condenser fans variable speed drive
Electronic system for checking the speed of condenser fans.
In case of system malfunction:
- turn off at mains
- open the electric control panel
- the variable speed drive is located inside the control panel.
Move the switch to position (1)
- close the electric control panel and reset the unit
- replace the variable speed drive as soon as possible
- having replaced it, move the variable speed drive to the automatic
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9.5 Electronic controller alarms When a fault is detected,the red Led in key (4) will be lit and a fault code displayed on
the screen (5).This code enables a speedy identification of the problem and should be
reported when making the service call.(The audible alarm will also sound if fitted).
High temperature alarm
The label (HI) and the cell temperature are intermittently displayed one after the
other.
Alarm relay activated
Causes: - The door has been opened too frequently
- The product load in the cell exceeds cell capacity
- The temperature of the products stored in the cell is too high
- Refrigeration system malfunction
Low temperature alarm
The label (LO) and the cell temperature are intermittently displayed one after the
other.
Alarm relay activated
Causes: -Electronic control unit malfunction
Solution: -Call technical assistance service
Ambient temperature sensor alarm
The label (EO) appears on the digital display.
Alarm relay is active
Causes: -The sensor is not connected
Solution: -Replace sensor
Evaporator sensor alarm
The label (E1) and the cell temperature are intermittently displayed one after the
other.
Causes: -The sensor is not connected
Solution: -Replace sensor
High pressure alarm
The label (HH) and the cell temperature are intermittently displayed one after the
other; led (4) lights up each time the high pressure switch is tripped.
If the high pressure switch is tripped more than 10 times in a one-hour period, the
label (PP) and the cell temperature will appear intermittently one after the other
on display (5), while the alarm relay will be activated together with led (4).
Room light switch, evaporator & condenser fan OFF.
To reset the alarm, disconnect the refrigeration unit, wait for a few seconds, then
restore connection.
Causes: -Ensure that the condenser fan is working properly
-Ensure that the condenser is clean.
9.6 Emergency system In case of fault or malfunctioning of the electronic control panel,if a short-term
replacing is not possible, an “EMERGENCY SYSTEM” can be used to keep the
unit running until a new control panel may be installed.
The “EMERGENCY SYSTEM” consists of a terminal board sited on the control
panel, fitted with 4 terminals , as shown in picture 15.
Proceed as follows to use the system:
1) Switch the electronic control panel off by pressing the key ON/OFF (10).
N.B.: The electronic control panel should remain in this condition during the whole
emergency period.
2) Switch the unit off.
3) Connect a thermostat (6 inductive Amps.) to the terminals E1 and E2 (Fig. 16).
4) Bridge terminals E2 and E3 as well as terminals E3 and E4 (Fig.16).
5) A wire comes out from nr. 30 on the card; it is welded in the card an connented
to terminal 4. Disconnect it and let it free.
6) Enter the thermostat bulb inside room.
7) Adjust the 'stat at the required temperature and switch the unit on.
E4 E3 E2 E1
Fig.15