Mitsubishi Heavy Industries AHU-KIT-SP Technical Manual
  1. Manuals
  2. Brands
  3. Mitsubishi Heavy Industries Manuals
  4. Air Handlers
  5. AHU-KIT-SP
  6. Technical manual
Mitsubishi Heavy Industries AHU-KIT-SP Technical Manual

Mitsubishi Heavy Industries AHU-KIT-SP Technical Manual

Air handling unit interface
Hide thumbs
Table of Contents

Advertisement

Quick Links

Download this manual
Manual No.'21・AHU-T-393
TECHNICAL MANUAL
AIR HANDLING UNIT INTERFACE
AHU-KIT-SP

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the AHU-KIT-SP and is the answer not in the manual?

Questions and answers

Summary of Contents for Mitsubishi Heavy Industries AHU-KIT-SP

  • Page 1 Manual No.'21・AHU-T-393 TECHNICAL MANUAL AIR HANDLING UNIT INTERFACE AHU-KIT-SP...

  • Page 2: Table Of Contents

    '21 • AHU-T-393 CONTENTS 1. AHU-KIT-SP - Overall composition ..............4 1.1 Product description ..................4 (1) What is Air Handling Unit? ................4 (2) What is AHU-KIT-SP? ................5 (3) Systems based on AHU Interface ...............6 (a) Single refrigerant line system ..............6 (b) Multiple refrigerant line system .............7 (c) AHU Interface input/output/in-output circuit .........8...
  • Page 3 '21 • AHU-T-393 (d) Correction coefficient C ..............12 (e) Correction coefficient D ..............12 (f) Calculation of total correction coefficient ..........12 (g) Calculation of rated capacity of outdoor unit ........13 (h) Confirmation of volume of internal heat exchanger ......13 (4) Select control method and settings ............14 (a) Capacity Control SW7-4: OFF ............14 (b) Temperature Control SW7-4: ON ............15 1.2.2 Sensor installation guidelines ..............17...
  • Page 4 '21 • AHU-T-393 3.3 Basic control ....................35 (1) Capacity distribution control by multiple unit connection ......35 (2) Rotation control ..................39 (3) Fault backup control ................40 4. Modbus communication ...................41 4.1 Communication specifications ..............41 4.2 Function ......................41 4.3 Data information ..................41 4.4 Communication –...

  • Page 5: Ahu-Kit-Sp Overall Composition

    '21 • AHU-T-393 1. AHU-KIT-SP Overall composition 1.1 Product description (1) What is Air Handling Unit? This system controls air-conditioning by means of a direct expansion air-heat exchanger, which uses the same refrigerant as for air-conditioning as the heat transferring media.

  • Page 6: What Is Ahu-Kit-Sp

    (2) What is AHU-KIT-SP? AHU-KIT-SP is the control kit (hereafter AHU Interface), which provides a refrigerant control for Air Handling Unit (hereafter AHU) equipped with a direct expansion heat exchanger to be connected to an outdoor unit for use at a shop.

  • Page 7: Systems Based On Ahu Interface

    '21 • AHU-T-393 (3) Systems based on AHU Interface (a) Single refrigerant line system ・ Single refrigerant line system is a system composed of single refrigerant line, which is controlled with one unit of AHU Interface (Master). ＡＨＵ Heat exchanger Heat exchanger temperature sensors Return air temperature...

  • Page 8: (B) Multiple Refrigerant Line System

    '21 • AHU-T-393 (b) Multiple refrigerant line system (Cascade control) ・ Multiple refrigerant line system is a system which installs multiple refrigerant lines on AHU. ・ Since multiple outdoor units can be connected in a system, it is adaptable to a large capacity. ・...

  • Page 9: (C) Ahu Interface Input/Output/In-Output Circuit

    '21 • AHU-T-393 (c) AHU Interface input/output/in-output circuit In-/output function of each connector is as follows. Heat exchange temperature sensor Thi-R2 Digital output Common Analog input Remote control Thi-R3 Thi-R1 Cascade communication spare Digital input Cascade Outdoor unit Thi-A AC220–240V 50 Hz AC220V 60Hz Return air Modbus...

  • Page 10: How To Use

    '21 • AHU-T-393 1.2 How to use 1.2.1 AIR HANDLING UNIT INTERFACE check sheet Flow to select the outdoor unit and design the heat exchanger is as shown below. (1) Confirmation of design conditions (2) Confirmation of heat exchanger specifications 　...

  • Page 11: Confirmation Of Design Conditions (Air Capacity, Suction Air Temperature/Humidity, Target Temperature/Humidity)

    '21 • AHU-T-393 (1) Confirmation of design conditions (Air capacity, suction air temperature/humidity, target temperature/ humidity) (a) Design air condition Cooling °CDB °CWB Exhaust air (EX) Heating °CDB °CWB Cooling °CDB °CWB Outdoor air (OA) Heating °CDB °CWB (b) Air capacity condition Supply air(SA) Circulating air(CA) Outdoor air(OA)

  • Page 12: Confirmation Of Heat Exchanger Specifications

    '21 • AHU-T-393 (2) Confirmation of heat exchanger specifications Design the heat exchangers according to following conditions. (a) Heat exchanger calculating conditions Cooling evaporator outlet Target evaporation 5 － 12deg.C 3deg.C superheat degree temperature Target Heating condenser outlet 30 － 47deg.C 1deg.C condensation subcool degree...

  • Page 13: Outdoor Unit Selection

    '21 • AHU-T-393 (3) Outdoor unit selection Select correct outdoor unit by applying the correction value adequate for the condition of use. Select the outdoor unit according to the following flow. (a) Confirmation of the range of use Confirm that the air condition, limit of pipe length, or other, fall within the range of use for air-conditioner. (b) Correction coefficient A Capacity correction according to air condition Calculate the capacity correction coefficient according to the operation mode.

  • Page 14: (G) Calculation Of Rated Capacity Of Outdoor Unit

    '21 • AHU-T-393 (g) Calculation of rated capacity of outdoor unit Confirm that the result of multiplying the rated capacity of selected outdoor unit by the total correction coefficient is larger than the required capacity. Calculate for the heating and the cooling respectively. When the capacity is insufficient, reselect the outdoor unit.

  • Page 15: Select Control Method And Settings

    '21 • AHU-T-393 (4) Select control method and settings The outdoor units can be controlled by one of two methods (Capacity Control or Temperature Control). Select the suitable control combination (No.1 － No.4) based on the equipment to be installed. Correct Master/Slave settings are required when using cascading control.

  • Page 16: (B) Temperature Control Sw7-4: On

    '21 • AHU-T-393 (b) Temperature Control SW7-4 ： ON (Set temperature control:18°C—30°C) System diagram control Digital Analog input not available Input/Output Set temperature AHU Interface AHU Interface AHU Interface Master Slave1 Slave15 Modbus control Master Slave15 Slave1 Compressor Compressor Compressor speed speed speed...
  • Page 17 '21 • AHU-T-393 <Confirmation of peripheral equipment and setting contents> ① Selected control system ② Confirmation of peripheral equipment to be connected to AHU Interface Item Model AHU control Remote control Modbus Option ③ Input/Output setting on AHU Interface Check functions to use. Connector Input setting Check...

  • Page 18: Sensor Installation Guidelines

    '21 • AHU-T-393 1.2.2 Sensor installation guidelines ● Install all sensors correctly. Each sensor has particular function so that it must be installed correctly. Otherwise, the system will not function correctly. ● Correct method for installation of temperature sensor (Example) When installing the temperature sensor, confirm that it optimally touches the face to measure.
  • Page 19 '21 • AHU-T-393 • Installation locations of the heat exchanger sensor ● Each heat exchanger requires 3 pieces of heat exchanger sensor. ● Connect heat exchanger sensor connectors to AHU Interface. ● Install each heat exchanger sensor correctly according to the following table. Heat exchanger Detected temperature Mounting...
  • Page 20 '21 • AHU-T-393 Heat exchanger Thi-R3 Each sensor has unique function, Important to fix to correct location. Th i -R1 If fixed to incorrect location, the system will not be controlled correctly, double check during commissioning. The Thi-R3 sensor diameter is larger than the others to avoid mistakes.
  • Page 21 '21 • AHU-T-393 3. Thi-R3 : On header section (without tape) a) It should be mounted on the header main pipe after collecting refrigerant during cooling. b) If the header main pipe runs horizontally, be sure to mount the sensor on the side part of the pipe to prevent from evaporating liquid refrigerant.
  • Page 22 '21 • AHU-T-393 Other items to be checked • 1. The indoor heat exchangers should have pockets for installing sensors. 2. The indoor heat exchanger temperature sensors should not be affected by other heat sources. • Avoid installing the sensors near any electrical devices that generate heat. •...
  • Page 23 '21 • AHU-T-393 7. The sensors should not make contact with other parts. 8. The sensor wiring should not be located where a person can touch it. If it can be touched, ensure it is covered by a protective tube with a thickness of 1 mm or more. (for safety reasons) 9.

  • Page 24: Single Cooling Line System

    '21 • AHU-T-393 2. Single cooling line system 2.1 Single cooling line system – Outline This is a system composed of single refrigerant line (1 outdoor unit), and is controlled with one unit of AHU Interface. ・ Since it is necessary to adjust PCB to Master setting, SW1 (Address) must be set at 0. ・...
  • Page 25 '21 • AHU-T-393 ● Rotary switch function ・ Set Master or Slave with SW1. ・ On the single refrigerant line system, make sure to set the interface address at 0. ・ SW2 – SW4 are spare switches. ・ SW5 and SW6 set Modbus communication addresses. SW5 is for ones place.
  • Page 26 '21 • AHU-T-393 ● Shorting plug function (Termination available/ not available) 1–2 Short : not available 2–3 Short : available 100Ω PCB of AHU Interface (Analog input switching) 1–2 Short : 0-10 V 2–3 Short : 4-20 mA ・ Functions can be changed by switching shorting plugs on PCB. ・...

  • Page 27: External In-/Output Terminals

    '21 • AHU-T-393 (2) External in-/output terminals Connector LED Connector Item Housing Color Function Remark Black Suction temperature Thi-A Yellow Spare Cannot use CNF connector. Heat exchanger Thi-R1 (U bend) Analog Heat exchanger input Yellow Thi-R2 (capillary) Heat exchanger Thi-R3 (Header) Green Capacity Control 0 –...

  • Page 28: Analog Input Circuit: X3 Connector

    '21 • AHU-T-393 (3) Analog input circuit: X3 connector Compressor speed can be controlled with analog input signal (0 – 10V/4 – 20mA). AHU Interface converts 0 – 10V/4 – 20mA signals within the rage of 0 – 100% to grasp the capacity necessary for AHU System.

  • Page 29: Digital Output Circuit

    '21 • AHU-T-393 (5) Digital output circuit ・ Digital output terminal outputs ON/OFF status with voltage. ・ Functions of each digital terminal are as follows. 1) X4a-X4d Digital output Voltage free a contact output Terminal Function ON (Shorted) OFF (OPEN) Outdoor Unit/ Error Normal...

  • Page 30: In-/Output Circuits

    '21 • AHU-T-393 (6) In-/output circuits ・ There are following input functions. Item Connector Housing Function Remote control Modbus (RS-485) Cascade control Input/ Output Cascade control (Reserve) Power (X0-2 is an empty port) 1) Remote control communication circuit ・ X1 connector: Remote control communication terminal (There is no polarity.) ・...

  • Page 31: Basic Control

    '21 • AHU-T-393 2.3 Basic control (1) Operation stop command to AHU system Run/Stop means to the system vary depending on the setting of SW7-4. Either one of Run/Stop means must be provided. (*1) Select either of the following ways to Run/Stop the AHU 1) Capacity Control (SW7-4 ：...

  • Page 32: Operation Mode Selection

    '21 • AHU-T-393 (2) Operation mode selection AHU Interface allows selecting two operation modes. ● Cooling mode ● Heating mode Operation mode can be changed in three ways. ● Operation mode switching by external input ● Operation mode switching by remote control operation ●...

  • Page 33: Temperature Control

    '21 • AHU-T-393 (3-2) Temperature Control Temperatures are set from the remote control or Modbus. It control the outdoor unit with the difference with the suction temperature sensor. Setting temperatures are determined as follows. 1) From the remote control – Refer to the instruction manual of remote control. 2) From Modbus –...

  • Page 34: Multiple Refrigerant Line System: Cascade Control

    '21 • AHU-T-393 3. Multiple refrigerant line system: Cascade control 3.1 Cascade control - Outline ● This is a system in which two or more refrigerant lines are used in one AHU system. Heat exchanger Heat exchanger temperature sensors Master Return air temperature sensor...

  • Page 35: Difference Of Specifications/Setting With Cascade Control Single Refrigerant System

    '21 • AHU-T-393 3.2 Difference of specifications/setting with cascade control single refrigerant system (1) Input switch in cascade control Switches are same as in the single refrigerant line. Check 2.2. (a) Address setting: SW1 · It is necessary to set Master for one unit of AHU Interface. Make sure to set SW1 (Address) of Master at 0. ·...

  • Page 36: Basic Control

    '21 • AHU-T-393 3.3 Basic control · AHU Interface master controls all Slaves. · All of Run/Stop, operation mode and thermostat ON/OFF are judged by Master. · Rotation control and fault backup control are enabled automatically. (1) Capacity distribution control in multiple unit connection ·...
  • Page 37 '21 • AHU-T-393 <Capacity control by Cascade control (SW7-4: OFF)> control Analog Input Digital 0�10V or 4�20mA Input/Output Modbus 0�100% Master Slave15 Slave1 Modbus Compressor Compressor Compressor control speed speed speed Capacity Control under Cascade Control (SW7-4 OFF): Example system ·...
  • Page 38 '21 • AHU-T-393 <Cascade control Temperature Control (SW7-4: ON)> control Digital Analog input not available Input/Output Set temperature Modbus Master Slave1 Slave15 control Compressor Compressor Compressor speed speed speed Capacity Control under cascade control (SW7-4 ON): Example system · AHU Interface Master controls the air-conditioning based on the difference between setting temperature and suction temperature sensor, and calculate the required speed to compressor.
  • Page 39 '21 • AHU-T-393 <Capacity step up control (SW8-2: ON)> · When a demand capacity is received from AHU control, this control operates outdoor units step by step or one after another, instead of operating all units simultaneously. · Although it takes time to raise the speed to the demand capacity, it allows to raise it gradually. ·...

  • Page 40: Rotation Control

    '21 • AHU-T-393 (2) Rotation control In order to keep the compressor operation time of each unit in the system at a constant level, AHU Interface (Master) controls such that the unit, of which the compressor operation time is the shortest, is operated preferentially. ·...

  • Page 41: Fault Backup Control

    '21 • AHU-T-393 (3) Fault backup control If any operating outdoor unit is stopped by the error stop, AHU Interface (Master) starts the backup operation of other normal outdoor units. · This control is enabled automatically. · Even if the unit stopped by error has been restored from the error, operation of the outdoor unit is not switched.

  • Page 42: Modbus Communication

    '21 • AHU-T-393 4. Modbus communication 4.1 Communication specifications X5 connector enables Modbus communication. (Modbus communication is effective on Master only.) Monitoring of AHU Interface and outdoor unit and some of setting contents for AHU Interface can be changed. Modbus communication specifications are as follows. Item Specification Note...

  • Page 43: Communication - Outline

    '21 • AHU-T-393 4.4 Communication - Outline Intervals between Modbus operating device and AHU-KIT-SP are as specified below. External control Demand Demand AHU I/F Master unit Response · Data length of demand frame is as shown below. Field Detail Data length...

  • Page 44: Input Register

    '21 • AHU-T-393 4.5 Input register There are following input registers (read only, 2-byte data) Data address Item Initial Range Unit Note 0 : Stop 30001 System Run/Stop display 0 - 65535 1 : Run 0 : Cooling 30002 Operation mode display 0 - 65535 1 : Heating 46(23 ℃...
  • Page 45 '21 • AHU-T-393 Data address Item Initial Range Unit Note 0 : Unconnected Connection status ： Slave1 31001 0 - 65535 1 : Connection 0 : Unconnected Connection status ： Slave2 31002 0 - 65535 1 : Connection 0 : Unconnected Connection status ：...
  • Page 46 '21 • AHU-T-393 Data address Item Initial Range Unit Note Compressor accumulated time 31039 0 - 65535 1H/count (Slave7) Compressor accumulated time 31040 0 - 65535 1H/count (Slave8) Compressor accumulated time 31041 0 - 65535 1H/count (Slave9) Compressor accumulated time 31042 0 - 65535 1H/count...
  • Page 47 '21 • AHU-T-393 Data address Item Initial Range Unit Note Heat exchanger temperature ： 31077 -3276 -32768 - 32767 0.1˚C/count Thi-R2 (Slave4) Heat exchanger temperature ： 31078 -3276 -32768 - 32767 0.1˚C/count Thi-R3 (Slave4) Heat exchanger temperature ： 31079 -3276 -32768 - 32767 0.1˚C/count Thi-R1 (Slave5)
  • Page 48 '21 • AHU-T-393 Data address Item Initial Range Unit Note Heat exchanger temperature ： 31108 -3276 -32768 - 32767 0.1˚C/count Thi-R3 (Slave14) Heat exchanger temperature ： 31109 -3276 -32768 - 32767 0.1˚C/count Thi-R1 (Slave15) Heat exchanger temperature ： 31110 -3276 -32768 - 32767 0.1˚C/count Thi-R2 (Slave15)
  • Page 49 '21 • AHU-T-393 Data address Item Initial Range Unit Note 0 : Normal 31146 Oil return display (Slave2) 0 - 65535 1 : Oil return 0 : Normal 31147 Oil return display (Slave3) 0 - 65535 1 : Oil return 0 : Normal 31148 Oil return display (Slave4)
  • Page 50 '21 • AHU-T-393 [Data address 30003 Set temperature display example] <0.5°C/count> 18=9°C 36=18°C 50=25°C 60=30°C [Data address 30007 Return air temperature display example] <0.1°C/count> 10=1°C 30=3°C 500=50°C 600=60°C Master/Slave1~15] < SW1 AHU Interface address > SW1 : 0=Master SW1 : 1=AHU Interface No.1 (Slave1) SW1 : 2=AHU Interface No.2 (Slave2) SW1 : 3=AHU Interface No.3 (Slave3) SW1 : 4=AHU Interface No.4 (Slave4)

  • Page 51: Retention Register

    '21 • AHU-T-393 4.6 Retention register There are following retention registers (read/write/2-byte) Data address Item Initial Range Unit Note 0 : Stop 40001 Run/Stop command 0 - 1 1 : Run 0 : Cooling 40002 Operation mode command 0 - 1 1 : Heating 40003 Set temperature command...

  • Page 52: Protection Control

    '21 • AHU-T-393 5. Protection control 5.1 Cooling frost protection To prevent frosting during cooling mode operation, the compressor-OFF if the AHU heat exchanger temperature (detected with Thi-R) drops to 1.0 °C or lower at 4 minutes after the compressor-ON. If the AHU heat exchanger temperature is 1.0 °C or lower after 5 minutes, the AHU Interface is controlled compressor-OFF.

  • Page 53: Compressor Inching Protection Control

    '21 • AHU-T-393 5.3 Compressor inching prevention control (a) 3-minute timer When the compressor has been stopped by the thermostat, remote control operation switch or anomalous condition, its restart will be inhibited for 3 minutes. However, the 3-minute timer is invalidated at the power on the electric power source for the unit.

  • Page 54: Error Display

    '21 • AHU-T-393 6. Error display 6.1 Abnormal temperature sensor (return air/heat exchanger) broken wire/short-circuit detection (a) Broken wire detection When the return air temperature sensor detects -50°C or lower or the heat exchanger temperature sensor detect -50°C or lower for 5 seconds continuously, the compressor stops. After 3-minute delay, the compressor restarts but, if it is detected again within 60 minutes after the initial detection for 6 minutes continuously, stops again (the return air temperature sensor: E7, the heat exchanger temperature sensor: E6).

  • Page 55: Trouble/Error Display

    Error confirmation If any error occurs in the system, Master outputs “Error” from the digital output X4a. If any error occurred on AHU-KIT-SP or outdoor unit, check the error with the following methods. · Error code display on remote control ·...
  • Page 56 MITSUBISHI HEAVY INDUSTRIES THERMAL SYSTEMS, LTD. 2-3 Marunouchi 3-chome, Chiyoda-ku, Tokyo 100-8332, Japan https://www.mhi-mth.co.jp/en/ Because of our policy of continuous improvement, we reserve the right to make changes in all specifications without notice. Copyright MITSUBISHI HEAVY INDUSTRIES THERMAL SYSTEMS, LTD.

Table of Contents