Itelco Industry MQH R 410A User manual

Service Manual
Chiller unit
MQH R 410A
Release Date Rev Review Date
november 2008 ----- -----

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MQH 11/08
CONTROL PANEL
The control panel allows the user to carry out all the operations related to the use of the controller in particular:
• To set the operation parameters
• To manage alarms
• To check the status
MQH R410A ELECTRONIC CONTROL
1 Display Display the status of the unit entering/leaving water and ambient air temperatures
compressor discharge pressure setpoint running times alarm code alarm history
etc.
2 Enter Key Select the display value or to program and modify system values
3 Scroll Key Scroll the menu
1 TECHNICAL CHARACTERISTICS
1.1 ELECTRICAL PERFORMANCE
Maximum Rating
Rated input voltage • 24 V Single-Phase 50 Hz or 60 Hz. Protected with on board fuse
Operating input voltage range • 20.4 – 26.4 Vac
No damage input voltage range • 16 – 32 Vac
Maximum current • 0.5A @ 24Vac
Minimum power factor • 0.92
Power consumption in stand-by • < 5W
Item Spec.
1
23

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MQH 11/08
1.2 GENERAL SPECIFICATIONS
• The control box is in compliance with European cur-
rent standard about emissions and immunity (e.m.c ).
• The miniCAC control board mounted in a IP20 plastic
case. The plastic is in compliance with UL94V0.
• Flash memory is used to store the program enable re-
download via 10 bit A/D converter in factory and at
site.
• During power failure with a duration more then 40
msec the control goes off and will random restart after
power comes back according the dip 5 position.
1.3 COMPATIBILITY WITH OTHER PRODUCTS AND SYSTEMS
1.3.1 ELECTRICAL INTERFACES
Analogue Input
N° Type
B1 NTC
B2 NTC
B3 NTC
B4 NTC/ratio
B5 NTC/ratio
Digital output
N° Chiller Type of relay Type
(AC motor rating)
1C-O Compressor 2A @ 230Vac N.A
2C-O Fan high speed or 2nd comp 4A @ 230Vac N.A
3C-O Fans motor or low speed See note 1 TRIAC
(see note 1)
4C-O Antifreeze heater 2A @ 230Vac N.A
5C-O Reversing valve 2A @ 230Vac N.A
6C-O Pump 4A @ 230Vac N.A
7C-O Unit alarm relay 2A @ 230Vac N.A
Digital Input
N° Chiller
ID1 Remote Unit Start/Stop
ID2 Cooling/Heating mode selection
ID3 Fan motor overload
(or 2nd compressor protection)
ID4 Compressor motor protection
ID5 Flow switch - Water diff. pressure switch
ID6 Low pressure switch
ID7 High pressure switch
ID8 Night Mode/Second setpoint

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MQH 11/08
2 START-UP & OPERATING INSTRUCTIONS
BMS Building management system
C1 Compressor
CP Condensing pressure
CSPT Cooling setpoint temperature
CDCO Cooling compensation offset
DEWT EWT derivative DEWT = (EWT(t) – EWT(t-1))/dt °C/min
EP Evaporating pressure
EWT Entering water temperature
EWTM Maximum entering water temperature
FP Freeze protection (minimum LWT)
FS Flow switch to detect sufficient water flow
HPC High pressure cut-out
HSPT Heating setpoint temperature
HDCO Heating compensation offset
LO Low fan speed
LOAT Low level of the external temperature
LSL Low speed limit
LWTM Minimum leaving water temperature
LWT Leaving water temperature
MCB Main control board
NM Night mode
OAT Outdoor air temperature
OD Outdoor
OFAN Outdoor fan
PGI Percent of glycol in the water
RC Reverse cycle (heat pump)
RV Reversing valve
SPT Setpoint temperature
ST Standard model (cooling only)
tC Comp timer
TH Trace heater for frost protection
Eph Low pressure heating adjust
tD Defrosting duration
THC Coil heater
BYP TXV by-pass during defrost
EPCR Evaporating Pressure Calculation (function of OAT)
EPIC Evaporating Pressure Iced Coil
EPCC EP Clean Coil
OPEr Parameter for mode selection in standard parameter
LOAt OAT limit valve for THC activation
ABBREVIATIONS
SYMBOL DESCRIPTION

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MQH 11/08
2.1 PRELIMINARY CHECK
The checks listed below shall be performed before start-
ing the unit.
• Check the section of power supply and grounding
cables; make sure that terminals are tightened and
check the correct operation of contactors with the
master switch open.
• Check that any voltage and phase variation in the
power supply dose not exceed the prefixed thresholds.
• Check that the components of the external water circuit
(user equipment filters power supply tank and reser-
voir if any) have been installed properly and accord-
ing to the manufacture’s instructions.
• Check the filling of the hydraulic circuits and make
sure that the fluid circulation is correct without any
trace of leaks and air bubbles.
• Check that the direction of rotation of the pumps is cor-
rect and that fluids have been circulating for at least
4 hours. Then clean the filters on the suction side of
the pumps.
• Adjust the liquid distribution network in such a way
that the flow rate is within the specified range.
• Check that the water quality is up to the specifications.
• Check that oil heaters if any have been turned on at
least 4 hours before (it is mandatory if the temperature
is under 15 °C).
2.2 BEFORE START-UP
Before you start-up the unit you must check the DIP switch
setup.
1 U BMS MODBUS ON
2 Not used OFF
3 No auto restart Auto Restart after power failure OFF
4 No OAT compensation OAT compensation ON
5 Cooling only unit Heatpump unit ON
6 No auto fan Auto FAN OFF
7 Pump ON when unit is ON Pump always ON OFF
8 Refrigerant R 407C Refrigerant R 410A ON
DIP NO. POSITION OFF POSITION ON FACTORY
SETUP
DIP SWITCH CONFIGURATION
** Turn ON the main switch of the power line.

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MQH 11/08
Display Description
C1 When compressor is operating
C1H Compressor in heat mode
DEIC defrost in operation
OFF Off mode
COOL Cool mode with no compressors on
HEAT Heat mode with no heating on
2.3 STARTING AND USING THE UNIT
• To start/stop the unit press for 5 secs the SCROLL key.
• To remotely stop the unit open the connection between
No. 7 and No. 8 on the terminal board.
• During the normal operation if the connection bet-
ween No. 5 and No. 6 terminal is closed the unit will
operate in heating mode. When the connection is
opened the unit will operate in cooling mode. If con-
nection 5-6 is open then OPER mode can be selected
by display.
• To modify operative mode or the setpoints press both
^ and > keys at the same time for 5s then the “OPEr”
message appears on the display. The parameters are
scrolled using the ^ button and selected using the > but-
ton. When selected the values can be changed by
using the ^ button to scroll from the present value to
max then min and can be selected by pushing the >
button.
After selection the menu will return to the beginning of
the same parameter change menu. If no button is pres-
sed for 10s the display reverts back to normal mode.

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MQH 11/08
TABLE LIST OF STANDARD PARAMETERS
Display Meaning Min. value Max value Step Default
value
OPEr Cooling/Heating mode selection COOL HEAT --- COOL
CSP Cooling Setpoint CSPL 23 0.5 12
HSP Heating Setpoint 20 47 1 40
gLY Glycol % 0 30 10 0
nigh Night mode 1 4 1 2
COAL CSPT compensation low limit 10 30 2 20
COAH CSPT compensation high limit 20 36 2 30
CDCO CSPT compensation 0 8 1 6
HDCO HCSPT compensation 0 15 1 8
HOAL HCSPT compensation low limit -10 10 1 -5
HOAH HCSPT compensation high limit 0 20 1 10
HPCE 1 auto reset for HPC alarm 0 1 1 0
ND Night mode differential 0 15 1 2
NFC Night mode fan change -4 4 1 2
Id Identification address 0 255 1 0
F0 Factory parameter 0 9 1 0
F1 Factory parameter 0 9 1 0
F2 Factory parameter 0 9 1 0

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MQH 11/08
TABLE LIST OF FACTORY PARAMETERS
DEFAULT VALUES ACCORDING TO DIP 8 SELECTION)
If you want to change the parameter value you must get the password from the factory or your authorized service support.
Display Meaning Unit Min. value Max value Step Default
value R410A
CSPL Minimum Cooling setpoint °C -5 14 1 8
FL Fluid paremeter 0 2 0.5 0
CPL Condensing Pressure Limit bar 0 50 0.5 40
TC0 Min. condensing temperature °C 0 100 1 20
TC1 Condensing temperature setpoint °C 0 100 1 30
TC2 Max condensing temperature °C 0 100 1 50
rpml Min. Triac output % 0 100 5 20
rpmh Max Triac output % 0 100 5 100
OAT1 Low OAT value in heating fan control °C 0 50 1 15
OAT2 High OAT value in heating fan control °C 0 50 1 30
LOL EP protection correction in cooling bar 0 1 0.2 0.4
EWTn EWTM max EWT (only in cooling) °C 16 40 1 24
Eph Low pressure heating adjust bar 0 1 0.1 0.3
tde Defrost cycle maximum duration min 2’ 10’ 1’ 5’
dd Delay time for defrost cycle min 10’ 60’ 5’ 35’
OCTi OCT defrost start value °C -10 10 1 -3
OCTe OCT defrost exit value °C 5 30 1 12
CPe CP defrost exit value bar 15 40 1 34
EPi EP defrost enter value bar 1.8 10 0.2 5.4
COF Off comp exiting defrost cycle flag 0 1 0
b4 B4 analog input type ntc rAt none Ntc
b5 B5 analog input type ntc rAt none rAt
• During normal operation the current value of entering
water temperature is displayed flashing alternatively
with the current status. To display other useful data go
to level 1 use the ^ button to scroll the menu and use
the > button to select the display value.

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MQH 11/08
DISPLAY DATA
Code Parameter Meaning
PARA READING PArA)
DE
TO (Triac output)
CSPT cooling setpoint enabled
HSPT heating setpoint enabled
tD last defrosting time
Code Parameter Meaning
SENSOR READING SEnS)
EWT entering water temperature
LWT leaving water temperature
CP discharge pressure
EP suction pressure
CPS saturated discharge temperature
EPS saturated suction temperature
OAT room air temperature
OCT sensor temperature in coil
Code Parameter Meaning
ALARM CODE READING
ALARM see last alarm exhisting
Code Parameter Meaning
HRS RUNNING HOURS HRS)
C1 Compressor 1 running
hours x 10
tC1 Compressor 1 running hours
by the last reset
Code Parameter Meaning
LOG LAST 10 ALARM LOG)
ALARM see alarm list
Code Parameter Meaning
STATUS READING STat)
C1 Compressor 1 on/off
RV
REVERSING VALVE
Rv on = heating mode
Rv off = cooling mode
EH ON or OFF
Pump Pump on/off
OFAN Fan on/off
dEIC defrost in operation
MODE OFF or COOL or HEAT

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MQH 11/08
• If an alarm is occurred the alarm code is displayed
but after 30’ even if the alarm is still active the display
shows again the mode but “Alarm” message is display-
ed for 2’ every 10’ when an alarm is active.
When we enter in Alarm list the first alarm code dis-
played is the last occurred.
ALARM SUMMARY
Fault as on display Fault description
ADC ADC error
CPF CP transducer failure out of range
EPF EP transducer failure out of range
REF Refrigerant leak- low pressures
CPnc CP transducer failure no change error
EPnc EP transducer failure no change error
CFC1 CP and EP no change compressor not operating (burn out or phase change)
EWTH EWT entering water temperature sensor short circuited
EWTL EWT entering water temperature sensor short disconnected
LWTH LWT entering water temperature sensor short circuited
LWTL LWT entering water temperature sensor short disconnected
OATH OAT outdoor air temperature sensor short circuited
OATL OAT outdoor air temperature sensor short disconnected
OCTH OCT coil temperature sensor short circuited
OCTL OCT coil temperature sensor short disconnected
HP High pressure protection automatic reset for first three times
HPC High pressure cut-out
LP Low pressure limit unit cut out
LO Leaving water temperature below allowed limits
HI EWT is too high
FS Flow switch opens low water flow
CF1 CF1 input open compressor 1 overload
OF1 OF1 input open outdoor fan overload
PF PF input open pump internal overload
LOu Low water volume
ConF Not allowed configuration
2.4 CHECKING THE OPERATION
Check the following:
• The temperature of the water entering the evaporator.
• The temperature of the water leaving the evaporator.
• The level of the water flow rate in the compressor and
in case of stabilized operation.
• The fan's current absorption.

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MQH 11/08
Check that the condensing and evaporation temperatu-
res during operation at high and low pressure detected
by the pressure gauges of the refrigerant are within the
following range:
(on the units not provided with HP/LP pressure gauges for
the refrigerant connect a pressure gauge to the
Schreader valves on the refrigeration circuit).
2.5 SYSTEM DIAGNOSTICS AND OPERATION AT FAULT CONDITIONS
FAULT RESPONSE
LWT sensor failure If in cooling then stop machine
EWT sensor failure Use EWT = LWT + 5
EWT & LWT failure together Stop machine
OAT sensor failure Use OAT = 35 (cooling) – 8 (heating).
Variable speed in heating always in maximum speed
CP sensor failure Fans to max speed when OAT > 20 °C
Fans to low speed when 15 °C < OAT < 20 °C
If OAT < 15 °C stop the unit in cooling only Disable vs.
In heating end defrost only with OCT > OCTe or Td > Tde
EP sensor failure In cooling mode correct CSPT to CSPT > FP + 7
In heating if OAT < 10 °C start defrost routine every 40 mins and end
defrost routine after 90 sec.
OCT failure or CP & OCT failure In heating if OAT < 10 °C start defrost routine every 40 mins and end
defrost routine after 90 sec.
Variable speed in cooling: always in maximum speed.
EP & CP failure Stop the unit
HP Approx. 13 to 18 °C above the temperature of the air entering the condenser
for R 410a units.
LP side Approx. the difference between the temperature of the leaving water and saturated evaporating
temperature must be in the 2 - 4 °C for R 410a units.