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Operating Manual 
20/38 

 

 EWAT_B 

 

 
 

4.10.2.1 Setpoint Reset by OAT (A/C units only) 

When the 

OAT

 is selected as 

Setpoint Reset

 option, the LWT active setpoint(AS) is calculated applying a correction to 

the basic setpoint that depends on the ambient temperature (OAT) and on the current Unit Mode (Heating mode or Cooling 
mode). Several parameters can be configured, and they are accessible from the 

Setpoint Reset

 menu, as shown below: 

 

 

 

 

 
Provided the unit is set in Cooling mode (Heating mode), the more the ambient temperature drops below (goes beyond) 
the  SROAT,  the  more  the  LWT  active  setpoint  (AS)  is  increased(decreased),  until  the  OAT  reaches  the  MROAT  limit. 
When the OAT overpasses the MROAT, the active setpoint does not increase(decrease) anymore, and it remains stable 
to its maximum(minimum) value, i.e.  AS = LWT + MR(-MR). 
 
 
 

 

Graph 2 Outside Ambient Temperature vs Active Setpoint  - Cooling mode(left)/ Heating mode(right) 

 

4.10.2.2 Setpoint Reset by External 4-20Ma signal 

When the 

4-20mA

 is selected as 

Setpoint Reset

 option, the LWT active setpoint(AS) is calculated applying a correction 

based  on  an  external  4-20mA  signal:  4  mA  corresponds  to  0°C  correction,  i.e.  AS  =  LWT  setpoint,  whereas  20  mA 
corresponds to a correction of the Max Reset (MR) quantity, i.e. AS = LWT se MR(-MR) as shown in the following 
table: 
   

Parameter 

Default 

Range 

Description 

Actual Reset  

 

 

Actual Reset shows which is the correction that will applied to the base 
setpoint 

Max Reset (MR)  

5.0°C 

0.0°C

10.0°C 

Max Reset setpoint. It represents the maximum temperature variation 
that the selection of the OAT option can cause on the LWT.  

Max Reset OAT (MROAT) 

15.5°C 

10.0°C

29.4°C 

It  represents  the  “threshold  temperature”  that  correspond  to  the 
maximum setpoint variation.  

Start Reset OAT(SROAT) 

23.8°C 

10.0°C

29.4°C 

It  represents the  “threshold  temperature”  of the OAT to  activate the 
LWT setpoint reset, i.e. the LWT setpoint is overwritten only if the OAT 
reaches/overpasses the SROAT.   

Delta T 

 

 

Is the actual evaporator delta temperature. Entering 

– Leaving water 

temperature 

OAT 

 

 

Actual outside ambient temperature 

Signal 

 

 

Actual input current read on the terminals Setpoint Reset 

SROAT 

OAT 

Active 
Setpoint 

LWT SP 

MR

 

LWT SP + MR 

MROAT 

Outside Temperature trend 

Outside Temperature trend 

SROAT 

OAT 

Active 
Setpoint 

LWT SP - MR 

MR

 

LWT SP  

MROAT 

Содержание EWAT_B

Страница 1: ...Air Cooled chiller with scroll compressors EWAT_B REV 00 Date June 2018 Supersedes Operating Manual D EOMAC01706 18EN...

Страница 2: ...Conservation 18 4 10 1 Demand Limit 18 4 10 2 Setpoint Reset 19 4 10 2 1 Setpoint Reset by OAT A C units only 20 4 10 2 2 Setpoint Reset by External 4 20Ma signal 20 4 10 2 3 Setpoint Reset by DT 21...

Страница 3: ...31 5 4 1 Discharge Temperature Sensor fault 31 5 4 2 CxOff OffSuctTempSen Suction Temperature Sensor fault 32 5 4 3 CxOff GasLeakage Gas Leakage fault 32 5 5 Circuit Rapid Stop alarms 32 5 5 1 CxOff C...

Страница 4: ...ervice or operate on the unit without having switched off the main switch 1 2 Before switching the unit Before switching on the unit read the following recommendations When all the operations and all...

Страница 5: ...ndensing Saturated Refrigerant Temperature DSH Discharge Superheat DT Discharge Temperature E M Energy Meter Module EEWT Evaporator Entering Water Temperature ELWT Evaporator Leaving Water Temperature...

Страница 6: ...ows to navigate between lines on a screen page and to increase and decrease changeable values when editing Pushing the wheel acts as an Enter Button and will jump from a link to the next set of parame...

Страница 7: ...p phase The controller needs time for starting Flashing Yellow Application not loaded Flashing Yellow Red Fail safe mode in case that the BSP upgrade was interrupted Flashing Red BSP Error software er...

Страница 8: ...light emitting diode located below the bell button All viewing and setpoint adjustments available on the unit controller are available on the remote panel Navigation is identical to the unit controlle...

Страница 9: ...to click on the value of the quantity to monitor and the following additional screen will become visible Depending on the web browser and its version the trend log feature may not be visible It s req...

Страница 10: ...erences about Remote On Off contact Generally this contact is used to bring out from the electrical panel the on off selector Some chiller models can be equipped with additional selectors Q1 Q2 used t...

Страница 11: ...programmed up to six time bands with a specific operating mode First operating mode starts at Time 1 ends at Time 2 when will start the second operating mode and so on until the latest Depending on un...

Страница 12: ...setpoints need to be defined From main menu with user password press on Setpoint Parameter Range Description Cool LWT 1 Ranges of the Cool Heat Ice setpoint are reported in the IOM of every specific...

Страница 13: ...ne of the previous cool mode Cool Cool w Glycol Ice Heat Cool Set in case a dual cool heat mode is required This setting implies an operation with double functioning which is activated through the Coo...

Страница 14: ...s limiting the unit capacity as the water temperature is dropping too quickly Capacity Limit Demand limit has been hit Unit capacity will not further increase Current Limit Maximum current has been hi...

Страница 15: ...g water temperature setpoint from network Capacity Limit Capacity limitation from network Refer to communication protocol documentation for specific registers addresses and the related read write acce...

Страница 16: ...point to stop a compressor Stage Up Delay Minimum time between the compressors startup Stage Down Delay Minimum time between the compressors shutdown Ice Cycle Delay Unit standby period during Ice mod...

Страница 17: ...Page View Set Unit Pumps Parameter Range Description Pump Control 1 Only Set to this in case of single pump or twin pump with only 1 operational f e in case of maintenance on 2 2 Only Set to this in...

Страница 18: ...mit level is regulated using an external 4 20 mA signal with a linear relationship shown in the picture below A signal of 4 mA indicates the maximum capacity available whereas a signal of 20 mA indica...

Страница 19: ...an external signal 4 20mA Setpoint Reset by Evaporator T EWT In order to set the desired setpoint reset strategy go to Main Menu Commission Unit Configuration Options and modify the Setpoint Reset pa...

Страница 20: ...ulated applying a correction based on an external 4 20mA signal 4 mA corresponds to 0 C correction i e AS LWT setpoint whereas 20 mA corresponds to a correction of the Max Reset MR quantity i e AS LWT...

Страница 21: ...increased if Cooling mode set or decreased if Heating mode is set of a maximum value equal to the Max Reset MR parameter Parameter Default Range Description Actual Reset Actual Reset shows which is th...

Страница 22: ...requency Returns the active frequency Parameter Default Range Description Max Reset MR 5 0 C 0 0 C 10 0 C Max Reset setpoint It represents the maximum temperature variation that the selection of the E...

Страница 23: ...rent Gateway address PrimDNS xxx xxx xxx xxx The current Primary DNS address ScndDNS xxx xxx xxx xxx The current Secondary DNS address Device POLxxx_xxxxxx The Host Name of the MTIII controller MAC xx...

Страница 24: ...Comm Start Off Stop the connection to DoS Start Start the connection to DoS Comm State Connection to DoS is off IPErr Connection to DoS cannot be established Connected Connection to DoS is establishe...

Страница 25: ...the heat recovery water temperature HR LWT Heat recovery leaving water temperature HR EWT Heat recovery entering water temperature HR EWT Sp Heat recovery entering water temperature setpoint value HR...

Страница 26: ...n the alarm log BadLWTReset String in the alarm snapshot BadLWTReset LWT reset input signal is out of range For this warning out of range is considered to be a signal less than 3mA or more than 21mA C...

Страница 27: ...heck flow switch connection and calibration Reset Local HMI Network Auto Reset 5 1 5ExternalEvent External Event This alarm indicates that a device whose operation is linked with this machine is repor...

Страница 28: ...ncrease the water flow Inlet temperature to the heat recovery is too low Increase the inlet water temperature Sensors readings entering or leaving are not properly calibrated Check the water temperatu...

Страница 29: ...Local HMI Network Auto 5 2 2UnitOffLvgEntWTempSen Evaporator Leaving Water Temperature LWT sensor fault This alarm is generated any time that the input resistance is out of an acceptable range Symptom...

Страница 30: ...th this unit operation This external device could be a pump or an inverter Symptom Cause Solution Unit status is Off All circuits are switched off with the normal shutdown procedure Bell icon is movin...

Страница 31: ...ater filter is clogged Check flow switch connections Reset Local HMI Network Auto 5 3 5UnitOff EXVDriverComm EXV Driver Extension Communication Error This alarm is generated in case of communication p...

Страница 32: ...good connected open Check for correct installation of the sensor on refrigerant circuit pipe Check for absence of water or humidity on sensor electrical contacts Check for correct plug in of the elect...

Страница 33: ...not properly connected open Check for correct installation of the sensor on refrigerant circuit pipe The transducer must be able to sense the pressure through the valve s needle Check for absence of w...

Страница 34: ...short circuit of the hot air blown from the fans of the same unit or even from fans of next chillers Check IOM for proper installation Entering water temperature at condenser is too high W C units Ch...

Страница 35: ...k the low pressure safeties settings Reset Local HMI Network Auto 5 5 6CxOff RestartFault Restart Fault This alarm is generated when the compressor internal protection trips Symptom Cause Solution Com...

Страница 36: ...W C units Check the cooling tower operation and settings Check the three way valve operation and settings Mechanical high pressure switch is damaged or not calibrated Check for proper operation of the...

Страница 37: ...erly connected Evaporating pressure sensor is not working properly Check for proper operation of evaporating pressure sensor Compressor on circuit is internally damaged with a mechanical problems for...

Страница 38: ...se of its content and the products and services presented therein Specification are subject to change without prior notice Refer to the data communicated at the time of the order Daikin Applied Europe...

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