
INSTALLATION AND MAINTENANCE MANUAL
FLOOR CEILING SLIM
FSTD SLIM - EC FLEX
Serie
FSTD SLIM - EC FLEX
Edition
R00
Models
FSTD SLIM-01
FSTD SLIM-02
FSTD SLIM-03
FSTD SLIM-04
FSTD SLIM-05
FSTD SLIM-01-4T
FSTD SLIM-02-4T
FSTD SLIM-03-4T
FSTD SLIM-04-4T
FSTD SLIM-05-4T

INVESTING IN QUALITY, RELIABILITY & PERFORMANCE
World Leading Design and Technology
Every product is manufactured to meet
the stringent requirements of the
internationally recognized ISO 9001
standard for quality assurance in design,
development and production.
Equipped with the latest air-conditioning test rooms
and manufacturing technology, we produce over
50,000 fan coil units each year, all conforming to the
highest international standards of quality and safety.
The Highest Standards of Manufacturing
All products conform to the Certificate
Europe directives (Machinery Safety,
Electromagnetic Compatibility and Low
Voltage), as required throughout the
European Community, to guarantee
correct standards of safety.
In order to guarantee the very highest standards and
performance, we manage every stage in the
manufacturing of our products. Throughout the
production process we maintain strict control,
starting with our extensive resources in research and
development through to the design and
manufacture of almost every individual component,
from molded plastics to the assembly of units and
controllers.
Quality Controlled from Start to Finish
All products conform to the “WEEE”
directive to guarantee correct standards
of environmental solutions.
Our highly trained staff and strict quality control
methods enable us to produce products with an
exceptional reputation for reliability and efficiency,
maintained over many years. As well as CE
certification and ISO 9001, several products ranges
have UL / ETL safety approval in the USA and Canada,
Eurovent performance and sound certification as
well as ROHS compliance for Europe, giving you the
confidence of knowing our company is the right
choice when selecting fan coil units.
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ALWAYS MAKE SURE THIS MANUAL REMAINS WITH THE UNIT. READ THIS MANUAL BEFORE PERFORMING ANY
OPERATION ON THE UNIT.
SK2019 FSTD-SLIM-EC-FLEX-001_01

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Table of Contents
A. Technical Data ...................................................................................................................................................................... 5
General Description ........................................................................................................................................................ 5
General Specification ..................................................................................................................................................... 6
2-Pipe Systems ........................................................................................................................................................ 6
4-Pipe Systems ........................................................................................................................................................ 7
Coil Data ........................................................................................................................................................................ 8
2-Pipe Systems ........................................................................................................................................................ 8
4-Pipe Systems ........................................................................................................................................................ 8
Sound Power Data .......................................................................................................................................................... 9
Dimensions .................................................................................................................................................................. 14
Valve Information (Optional) ........................................................................................................................................ 15
B. Installation ......................................................................................................................................................................... 18
Safety Precautions ........................................................................................................................................................ 18
Installation and Location .............................................................................................................................................. 19
Front Panel Removal .................................................................................................................................................... 20
Electrical Connection .................................................................................................................................................... 20
Piping Connections ....................................................................................................................................................... 22
Valve and External Drain Pan Installation ..................................................................................................................... 23
C. Maintenance ...................................................................................................................................................................... 25
General Maintenance ................................................................................................................................................... 25
Regular Maintenance ................................................................................................................................................... 25
Filter Installation & Cleaning ........................................................................................................................................ 25
Fan Motor Assembly Maintenance ............................................................................................................................... 26
Water Fittings Interchange ........................................................................................................................................... 26
D. Control Specifications: Complete Function PCB – TOTAL Type Control .............................................................................. 27
I/O Port Definitions ...................................................................................................................................................... 27
Wiring Diagrams .......................................................................................................................................................... 28
Standard EC-TOTAL Type Control PCB .................................................................................................................... 28
Master-Slave Networking Wiring Diagram ............................................................................................................. 29
Configuration Settings .................................................................................................................................................. 30
Control Logics for 2-Pipe System ................................................................................................................................... 32
With Valve Configuration ....................................................................................................................................... 32
Without Valve Configuration ................................................................................................................................. 35
Control Logics For 4-Pipe System .................................................................................................................................. 37
Sleep Mode .................................................................................................................................................................. 39
Auto Fan Speed ............................................................................................................................................................ 39
Modulating Valve Control Under Energy Saving Mode ................................................................................................. 39
Buzzer .......................................................................................................................................................................... 39
Auto Restart ............................................................................................................................................................... 39
On/Off Switch On The Front Panel .............................................................................................................................. 40
Electric Heater Safety Switch ...................................................................................................................................... 40
SK2019 FSTD-SLIM-EC-FLEX-001_01

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Low Temperature Protection of Indoor Coil in Winter ................................................................................................. 40
E. Networking System ............................................................................................................................................................ 41
Master-Slave Network .................................................................................................................................................. 41
Master Unit Control Settings .................................................................................................................................. 41
Master-Slave Network Setup ................................................................................................................................. 42
Master-Slave Communication Method ................................................................................................................... 44
Open Modbus protocol ................................................................................................................................................. 45
F. Control Specifications: Flexible Function PCB – FLEXI Type Control .................................................................................... 48
Features ........................................................................................................................................................................ 48
I/O Port Definitions ....................................................................................................................................................... 48
Onboard Configuration ................................................................................................................................................. 48
Wiring Diagrams ........................................................................................................................................................... 49
Standard EC-FLEXI Type Control PCB....................................................................................................................... 49
Control Logics Specification ........................................................................................................................................... 50
Unit Power On/Off ................................................................................................................................................. 50
Alarm Protection and Error Display ........................................................................................................................ 50
Drain Pump Operation ........................................................................................................................................... 50
Modulating Signal Input ......................................................................................................................................... 50
Electrical Heater Operation .................................................................................................................................... 50
Low Temperature Protection of Indoor Coil in Winter ............................................................................................ 50
G. User Interface .................................................................................................................................................................... 51
Remote Handset for TOTAL Type Control ...................................................................................................................... 51
Wired Wall Pad Controller ............................................................................................................................................ 52
Thermostat for EC-FLEXI Type Control .......................................................................................................................... 56
LED display ............................................................................................................................................................ 56
Parameters setting ................................................................................................................................................ 57
AC/EC fan coil thermostat ............................................................................................................................................ 58
I/O table ................................................................................................................................................................ 59
Thermostat control specification ........................................................................................................................... 60
2-pipe thermostat control specification (Parameter 17=0) .................................................................................... 60
4-pipe thermostat control specification (Parameter 17=1) .................................................................................... 62
2-pipe +floor heating control specification (Parameter 17=2) ................................................................................ 64
MODBUS Communication Protocols for Thermostat ............................................................................................. 65
H. Sensor Resistance R-T Conversion Table ............................................................................................................................ 67
I. Troubleshooting .................................................................................................................................................................. 69
J. Accessories Descriptions ..................................................................................................................................................... 70
Electrical Heater ............................................................................................................................................................ 70
Auxiliary External Drain Pan .......................................................................................................................................... 71
Supporting Feet ............................................................................................................................................................. 71
SK2019 FSTD-SLIM-EC-FLEX-001_01

Model Code Nomenclature
Flexible function onboard PCB with zone
control functionality.
Chilled/Hot Water, 4-Pipe
Unit Sizes. See General Specification
section A for cooling and heating
capacities
Super Slim Universal Unit
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SK2019 FSTD-SLIM-EC-FLEX-001_01

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SK2019 FSTD-SLIM-EC-FLEX-001_01
Technical Data
General Description
The product represents all-in-one solution for cooling, heating and dehumidification. It achieves high energy saving levels as it
can be combined with low-temperature heat generators such as heat pump, condensing boilers and solar collectors. With its
sophisticated temperature regulator, it guarantees thermal comfort in every season. It heats and cools extremely quickly and
once the desired temperature is reached it maintains it accurately and silently.
STRUCTURE
The bearing structure is made of galvanized sheet-steel with holes for attaching the structure to the wall/ceiling. The “V” type
drain pan is used in the unit which ensure the unit can be installed vertically and horizontally. Fire resistant insulation is fitted
internally to provide both thermal and acoustic insulation.
FASCIA
The RAL9010 fascia is made of steel-sheet with electrostatic coating which is resistant to rust, corrosion, chemical agents,
solvents, aliphatic compounds and alcohols.
AIR DELIVERY GRILLE
The air delivery grill is made from ABS, which color is RAL9010.
HEAT EXCHANGER
The heat exchanger is a highly efficient coil in which copper pipes and aluminum fins are fixed by mechanical expansion. Coil
connections are provided with an anti-torsion system, hand air vent and water purge valves.
Coils are tested at the pressure of 25 bar and recommended for operating at 8 bar.
Blower and Motor
The unit incorporates only specially designed and tested EC motors, allowing the blower wheel to provide optimum
performance in airflow-efficiency and quiet operation.
AIR FILTER
The air filter is made of ABS with Nylon filter. It is easy to removing and cleaning, which can be cleaned by rinsing with water
or by gently vacuuming it.
Microprocessor controls (EC-TOTAL type)
The PCB (printed circuit board) Modbus microprocessor controls functionality of the indoor fan motor, water valves (ON/OFF)
and electric heater (optional), to maintain room conditions at a user-defined set point. Temperature settings, fan speeds and
other control functions can be changed by either infrared handset or wired wall pad controller.
Electro-mechanical controls (EC-FLEXI type)
A 230VAC signal from the thermostat which working power is from L and N or from indoor room to terminal H/M/L supplies
power to limited PCB. When any of H/M/L is powered ON, the stepping motor is working and open the louver at maximum
position. When all of H/M/L is powered OFF, the stepping motor will close the louver. The condensate pump will run
continuously, as long as coil temperature is less than 15°C. Alarm notification and zone control function are available. 40VA
24vac transformer is equipped with unit optionally, which is used to supply 24Vac power to thermostat and modulating valve.

General Specification
~TOTAL: Complete function onboard PCB with integrated group control
functionality.
~FLEXI: Flexible function onboard PCB with zone control functionality.
Sensible
Cooling
Capacity
Max. Electric Heater
Capacity
Fan Motor Running
Current @ H
Construction and Packing
Data
Condensate Drainage
Connection
a. Cooling mode (2-pipe):
b. Heating mode (2-pipe):
- Return air temperature: 27C DB/ 19C WB.
- Return air temperature: 20C.
- Inlet/ outlet water temperature: 7C/ 12C.
- Inlet/ outlet water temperature: 45C/ 40C.
2-Pipe Systems
Product range: FSTD SLIM-EC Super Slim Universal Fan Coil with EC Motor
FSTD SLIM~-EC Super Slim Universal Unit 2-pipe with EC Motor
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SK2019 FSTD-SLIM-EC-FLEX-001_01

4-Pipe Systems
~TOTAL: Complete function onboard PCB with integrated group control
functionality.
~FLEXI: Flexible function onboard PCB with zone control functionality.
Sensible Cooling
Capacity
Fan Motor Running Current @ H
Water Content – Chill Water
Water Content – Hot Water
Construction and
Packing Data
Condensate Drainage Connection
b. Heating mode (4-pipe):
- Return air temperature: 27C DB/ 19C WB.
- Return air temperature: 20C.
- Inlet/ outlet water temperature: 7C/ 12C.
- Inlet/ outlet water temperature: 65C/ 55C.
Product range: FSTD SLIM-4T~-ECM Super Slim Universal Unit 4-pipe with EC Motor
FSTD SLIM-4T~-ECM Super Slim Universal Unit 4-pipe with EC Motor
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SK2019 FSTD-SLIM-EC-FLEX-001_01

Coil Data
2-Pipe Systems
4-Pipe Systems
Cooling Coil
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FSTD SLIM-01-4T
FSTD SLIM-02-4T
FSTD SLIM-03-4T
FSTD SLIM-04-4T
FSTD SLIM-05-4T
Heating Coil
Model
FSTD SLIM-01-4T
FSTD SLIM-02-4T
FSTD SLIM-03-4T
FSTD SLIM-04-4T
FSTD SLIM-05-4T
SK2019 FSTD-SLIM-EC-FLEX-001_01

Valve Information (Optional)
Valve Code
(valve body + ON/ OFF
thermoelectric actuator)
Valve Body Dimensions (mm)
Valve Code
(valve body + ON/ OFF
thermoelectric actuator)
Valve Body Dimensions (mm)
2-Way 3/4” Valve Body
3-Way 3/4” Valve Body
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Differential Pressure Chart
SK2019 FSTD-SLIM-EC-FLEX-001_01

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SK2019 FSTD-SLIM-EC-FLEX-001_01
Installation
Safety Precautions
• When installing, performing maintenance or servicing Daitsu fan coil units observe the precautions
stated in this manual as well as those stated on the labels attached to the unit.
• Ensure all local and national safety codes, laws, regulations, as well as general electrical and
mechanical safety guidelines are followed for installation, maintenance and service.
• The appliance is for indoor use only.
• Ensure the correct power supply is provided.
• If the power supply cord is damaged, it must be replaced by qualified personnel.
• Installing and servicing fan coil unit should be performed by qualified service personnel only.
• This appliance is not intended for use by persons (including children) with reduced physical, sensory
or mental capabilities, or persons lacking in experience and knowledge of the appliance, unless they
have been given supervision or instruction concerning it.
• User of this appliance is responsible for his/her own safety.
• Warranty shall be voided if installation instructions and safety precaution stated in this manual are
not observed.
• The unit should only be switched off by using the ON-OFF button on the control interface.
CAUTIONS
Before any service or maintenance operations turn off the mains electrical supply.
DO NOT turn OFF the main power supply when the unit is operating. Turn off the
unit BEFORE turning off the main power

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SK2019 FSTD-SLIM-EC-FLEX-001_01
Installation and Location
The unit location should be established by the installation designer, services engineer or by a technically competent person
before installation. It should take into account the technical requirements as well as the relevant current laws and
regulations. The fan coil should be installed by a qualified company, also in accordance with the relevant laws and regulations
of the country of installation.
The fan coils are designed for exposed installation. All the models are designed to be floor free standing, wall mounted or
suspended from the ceiling. Installation should allow the treated air to circulate freely throughout the room and leave
sufficient space to access the unit, in order to carry out maintenance or servicing operations.
FOR FLOOR FREE STANDING
1. Open the top left and right covers to loosen the 8 screws.
2. Lift and remove the front panel.
3. Install the unit on the wall with ABS supporting feet.
4. Complete the hydraulic connection and check for leakage.
5. Complete the electrical connection as shown in the wiring
diagrams.
6. Remount the front panel, return air grille and filter.
FOR WALL-MOUNTED WITH BOTTOM RETURN
1. Open the top left and right covers to loosen the 8 screws
2. Lift and remove the front panel.
3. Keep a minimum clearance of 80mm from the floor.
4. Secure the mounting brackets to the wall, then suspend the unit
by the mounting brackets, as shown in figure.
5. Complete the hydraulic connection and check for leakage.
6. Complete the electrical connection as shown in the wiring
diagrams.
7. Remount the front panel, return air grille and filter.
FOR CEILING-MOUNTED
1. Open the top left and right covers to loosen the 8 screws.
2. Lift and remove the cover.
3. Secure the mounting brackets to the ceiling, then suspend the
unit by the mounting brackets. To correctly position flanges
and brackets, see the dimensional data.
4. Complete the hydraulic connection and check for leakage.
5. Complete the electrical connection as shown in the wiring
diagrams Make electrical connection as shown in the wiring
diagrams.
6. Remount the front panel, return air grille and filter.