Stulz EC Tower ECD 91 User manual

EC Tower
ECD/U 091, 181, 251 (Version 07)
Technical manual
Precision Air Conditioning Units
400V/50Hz/3Ph/N/PE
Index G22
Issue 1.2019

EN/01.2019/G22 © STULZ GmbH – all rights reserved
EC TOWER TECHNICAL MANUAL
Editor
STULZ GmbH
Holsteiner Chaussee 283
22457 Hamburg
ABOUT STULZ
Since it was founded in 1947, the STULZ company has
evolved into one of the world’s leading system suppliers of
air-conditioning technology.
Since 1974 the group has seen continual international
expansion of its air conditioning technology business, spe-
cialising in A/C for data centres and telecommunications
installations.
STULZ has ten production plants (2 in Germany, Italy,
the USA, Great Britain, Spain, 2 in China, Brazil and India)
and twenty subsidiaries (in Germany, France, Italy, Great
Britain, Belgium, Brazil, the Netherlands, New Zealand,
Mexico, Austria, Poland, Spain, Singapore, China, India,
Indonesia, South Africa, Sweden, Australia and the USA).
The company also co-operates with sales and service
partners in over 140 other countries, and therefore boasts
an international network of air-conditioning specialists.

© STULZ GmbH – all rights reserved EN/01.2019/G22
EC TOWER TECHNICAL MANUAL
Reliability for small and
medium-sized IT rooms
Dear customer,
thank you for having chosen the EC Tower from STULZ.
If you need precise, reliable and cost effective air conditioning for small equipment and server
rooms, the EC Tower series is an energy efficient and long-lasting series that fits the bill. The units
require little floor space, and their compact size means they can be integrated in existing server
rooms without problem.
For inquiries and service, please contact your local STULZ partner.
At www.stulz.com you will find a partner near you as well as the entire global STULZ sales
network.

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EC TOWER TECHNICAL MANUAL
Contents
1. Information on this document ...............................................................................................7
1.1 Scope.................................................................................................................................................................... 7
1.2 Presentation conventions .............................................................................................................................. 7
2. Safety.......................................................................................................................................7
2.1 Safety instructions............................................................................................................................................ 7
2.2 Handling refrigerants....................................................................................................................................... 8
2.3 Duties of the operator...................................................................................................................................... 8
2.4 Other applicable documents......................................................................................................................... 9
3. Residual risks........................................................................................................................10
4. Transport / Storage ..............................................................................................................12
4.1 Delivery of units .............................................................................................................................................. 12
4.2 Transport........................................................................................................................................................... 12
4.3 Storage.............................................................................................................................................................. 13
5. Description............................................................................................................................14
5.1 Type code.......................................................................................................................................................... 14
5.2 Proper use ........................................................................................................................................................ 15
5.3 Improper use.................................................................................................................................................... 15
5.4 EC Tower method of operation.................................................................................................................. 16
5.5 EC Tower sizes and versions....................................................................................................................... 20
5.5.1 Sizes ......................................................................................................................................................... 20
5.5.2 Unit versions.......................................................................................................................................... 20
5.6 Heater method of operation....................................................................................................................... 21
6. Technical data .......................................................................................................................22
6.1 Application limits ............................................................................................................................................ 22
6.2 EC Tower Technical Data ............................................................................................................................. 24
6.3 Electrical data and circuit diagram of EC Tower................................................................................... 27
6.4 Dimensional drawings .................................................................................................................................. 28
6.5 Operating and connection data of EC Tower ....................................................................................... 29
6.5.1 ECU/D 091 size 1 - Version 07 ..................................................................................................... 29
6.5.2 ECU/D 181 size 2 - Version 07 ..................................................................................................... 31
6.5.3 ECU/D 251 size 2 - Version 07 ..................................................................................................... 33
7. Installing the EC Tower .........................................................................................................35
7.1 Setting up.......................................................................................................................................................... 35
7.2 Opening the EC Tower.................................................................................................................................. 36
7.3 Connecting the pipes.................................................................................................................................... 38
7.3.1 Location of refrigerant connections.............................................................................................. 38
7.4 Installing the drain.......................................................................................................................................... 42
7.4.1 Types of installation............................................................................................................................. 42
7.5 Installing the refrigerant circuit.................................................................................................................. 46
7.6 Establishing the conductivity of the feed water................................................................................... 47
7.7 Connecting the steam humidifier to the feed water............................................................................ 48
7.7.1 On-site preparations........................................................................................................................... 48
7.7.2 Connecting the Downflow unit to the feed water...................................................................... 48
Subject to technical modifications.

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7.7.3 Connecting the Upflow unit to the feed water............................................................................ 50
7.8 Electrically connecting the EC Tower...................................................................................................... 52
7.8.1 Circuit diagram ..................................................................................................................................... 53
7.8.2 Electrical wiring diagram................................................................................................................... 53
7.8.3 Electrically connecting the EC Tower to junction box 1.......................................................... 54
7.9 Connecting the outdoor unit to the EC Tower....................................................................................... 55
7.9.1 Connecting the outdoor unit electrical supply to junction box 1 ......................................... 55
7.9.2 Connecting the outdoor unit signal lines in junction box 2 .................................................... 56
7.10 Setting the DIP switches of the printed circuit boards in junction box 2.................................. 57
8. Starting up the EC Tower......................................................................................................59
9. EC Tower maintenance .........................................................................................................63
9.1 Safety instructions......................................................................................................................................... 63
9.2 Maintenance intervals .................................................................................................................................. 64
9.3 Air circuit maintenance................................................................................................................................. 64
9.3.1Replacing the filter of Upflow units................................................................................................ 65
9.3.2Replacing the filter of Downflow units.......................................................................................... 66
9.3.3Replacing the filter in the filtration box in Downflow units..................................................... 69
9.4 Unit in general ................................................................................................................................................. 70
9.5 Heater maintenance...................................................................................................................................... 70
9.6Steam humidifier maintenance.................................................................................................................. 70
9.7 Replacing the solenoid valve coil of the optional water warningsystem..................................... 70
10. Troubleshooting..................................................................................................................71
10.1 Troubleshooting the EC Tower................................................................................................................ 71
10.2 Troubleshooting the heater...................................................................................................................... 72
10.3 Troubleshooting the steam humidifier.................................................................................................. 72
10.4 Troubleshooting the optional water warning system....................................................................... 72
11. Dismantling and disposing of the EC Tower .....................................................................73
12. Spare parts..........................................................................................................................74
13. Options................................................................................................................................75
13.1 Overview......................................................................................................................................................... 75
13.2Installing the condensate pump............................................................................................................. 78
13.2.1 Safety instructions............................................................................................................................ 78
13.2.2 Checking the product package.................................................................................................... 79
13.2.3 Other applicable documents for installing and operating the condensate pump....... 79
13.2.4 Selecting the installation location ............................................................................................... 79
13.2.5 Electrically connecting the condensate pump to EC Tower size 1................................... 82
13.2.6 Electrically connecting the condensate pump to EC Tower size 2................................... 84
13.3Installing the blow-out plenum for Upflow units............................................................................... 87
13.4Installing the blow-out plinth for Downflow units............................................................................. 88
13.5Installing the raised floor stand............................................................................................................... 91
13.6Installing the adapter panel for Upflow units...................................................................................... 94
13.6.1 Installing the adapter panel for flexible canvas fittings or duct connections................ 95
13.6.2 Installing the duct connection....................................................................................................... 95
13.7Installing the flexible canvas fitting ....................................................................................................... 96
13.8Installing the louver damper for Upflow units..................................................................................... 98
13.8.1 Installing the louver damper .......................................................................................................... 99
13.8.2 Electrically connecting the louver damper............................................................................... 99

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13.9Installing the louver damper for Downflow units............................................................................ 100
13.9.1 Installing the louver damper ....................................................................................................... 101
13.9.2 Electrically connecting the louver damper............................................................................ 102
13.10Installing the filtration box .................................................................................................................. 103
13.11 Installing the temperature and humidity sensor B03 for supply air...................................... 105
13.11.1 Installation conditions................................................................................................................ 105
13.11.2 Installation diagram.................................................................................................................... 106
13.11.3 Electrically connecting the T/H sensor B03 ..................................................................... 106
13.12 Installing the water warning system ................................................................................................ 108
13.12.1 Safety instructions...................................................................................................................... 108
13.12.2 Other applicable documents................................................................................................... 109
13.12.3 Selecting the installation location ......................................................................................... 109
13.12.4 Water warning system versions and required components.......................................... 110
13.13Version 1: Installing a water warning system with sensor, withoutsolenoid valve........... 112
13.13.1 Version 1 connection diagram ............................................................................................... 113
13.13.2Option for versions 1 and 2: Installing the additional sensor (B17)........................... 118
13.13.3 Selecting the installation location ......................................................................................... 118
13.13.4 Additional sensor connection diagram................................................................................ 119
13.14Version 2: Installing a water warning system with sensor and solenoid valve................... 121
13.14.1 Version 2 connection diagram ............................................................................................... 121
13.14.2 Option for versions 1 and 2: Installing the additional sensor (B17) ........................... 124
13.15Version 3: Installing the BMS contact for the water warning system................................... 125
13.15.1 Version 3 connection diagram: BMS contact for water warning system.................. 125
13.16WIB 8000................................................................................................................................................ 127
13.16.1 Installation instructions............................................................................................................. 127
13.16.2 Technical data and dimensions .............................................................................................. 127
13.16.3 Installing the WIB 8000............................................................................................................ 128
13.16.4 Connection diagram for WIB 8000 ...................................................................................... 129
13.16.5 Starting up the WIB 8000........................................................................................................ 130
13.17Installing the RS485 EBUS expansion board............................................................................. 132
13.18Installing the front door for Upflow units ....................................................................................... 135
13.18.1 Installation instructions............................................................................................................. 135
14. Annex................................................................................................................................ 139
14.1 Technical Manual for CompTrol Interface III k for EC Tower........................................................ 139
14.2 Steam humidifier OEM User Manual ................................................................................................. 164
14.2.1 Identification of the steam humidifier OEM........................................................................... 164
14.3 Data sheet for optional condensate pump ...................................................................................... 187
14.4 Data sheet for optional water warning system............................................................................... 189
14.4.1 Data sheet for 72.01 level controller...................................................................................... 189
14.4.2 Data sheet for 72.11 sensor...................................................................................................... 190
14.4.3 Data sheet for solenoid valve..................................................................................................... 191
14.4.4 Data sheet for relay K08 and BMS contact K17 ................................................................ 194
14.5 Data sheet for temperature and humidity sensor B03 for supply air...................................... 196
14.6 Installation instructions for louver damper servo motor.............................................................. 200
15. CE Declaration of Conformity for the EC Tower ............................................................. 204

7© STULZ GmbH – all rights reserved EN/01.2019/G22
EC TOWER TECHNICAL MANUAL
1. Information on this document
This Technical Manual contains detailed information on installation, operation, maintenance and
troubleshooting.
Always keep the Technical Manual to hand at the location of use.
Make sure that persons responsible for operating and working on the product have fully read and understood
this manual. Please call the Service Center if you have any questions.
1.1 Scope
This Technical Manual applies to the EC Tower version 07 or later (sizes 1 and 2). You can find the version
number on the rating plate of the EC Tower (see section “5.1 Type code“ on page 14). The sizes are
described in section “5.5.1 Sizes“ on page 20.
1.2 Presentation conventions
Safety and warning notices are indicated by signal words. The signal words indicate hazard levels with risks of
injury of varying degrees of severity. The signal word IMPORTANT indicates a risk of property damage.
DANGER Death or serious injury due to a high-risk hazard
WARNING Death or serious injury due to a medium-risk hazard
CAUTION Slight injury due to a low-risk hazard
NOTICE Damage to property or the environment
NOTE Special tips on getting the best out of the product
2. Safety
2.1 Safety instructions
General
These operating instructions contain basic information which is to be complied with for installation, operation
and maintenance. They must therefore be read and complied with by the fitter and the responsible trained
staff/operators before assembly and commissioning. They must be permanently available at the place where
the system is used.
NOTE
This air conditioning unit uses refrigerant R410A. Refrigerants are hydrofluorocarbons (HFCs)
that are either volatile or are liquefied under pressure and highly volatile. They are non-combus-
tible and, if handled correctly, are not hazardous to health.

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• Have the work performed only by expert personnel.
• Comply with accident prevention regulations.
• When lifting and lowering, remain outside the danger zone, not under the load.
• Secure to prevent parts falling over.
• Do not disable safety equipment.
• For electrical connections, comply with the relevant VDE, EN and IEC standards and connection require-
ments of the electricity supply companies.
• Switch off the power supply to the unit when working on it.
• After installation and maintenance work: check the fan for loose parts and tools before switching on the air
conditioning unit.
• Remove loose parts and tools from the fan before switching on the air conditioning unit.
• Wear personal protective equipment when working on the refrigerant circuit.
2.2 Handling refrigerants
• Get qualied refrigeration technicians to carry out the work.
• Safety glasses and safety gloves are to be worn.
• Liquid refrigerant must not get onto the skin (risk of burns).
• Only use in well ventilated areas.
• Do not inhale refrigerant vapours.
• Refrigerants have a narcotic effect when inhaled in high concentrations.
• The room is to be evacuated immediately if high concentrations of refrigerant suddenly occur.
• If unavoidable work is required in the presence of a high concentration of refrigerant, breathing
apparatus must be worn. This does not mean simple filter masks. Comply with breathing protection
data sheet.
• Do not eat, drink or smoke at work.
• Warning against intentional misuse.
• It is absolutely essential to comply with the rst aid measures if accidents occur.
• Refrigerants containing FCs contribute to the global warming and with this to climate changes. The
FCs must therefore be disposed of in accordance with the regulations, i.e. only by companies spe-
cially qualified and licensed as recognised disposal companies for refrigerants.
• Responsability for correct disposal of refrigerant and system parts is incumbent on the operator.
2.3 Duties of the operator
The following requirements relate to the operation of refrigerating plants within the European Community.
• The used components must correspond to the pressure equipment guide-line 2014/68/EU and EN 378
part 14.
• Independent of the design, the equipment and inspection before the delivery, also the operator of such
plants has duties according to EN 378 and national regulations.
This concerns the installation, the operation and the repeated inspection:
• Installation: according to EN 378
• Operation: Determination of emergency measures (accidents, malfunctions)
Creation of an abbreviated instruction and notification (template page)
a. A unit protocol must be kept.
b. To be stored in the proximity of the unit
c. Access for competent staff in case of repairs and repeated inspection must be ensured.

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2.4 Other applicable documents
Besides this technical documentation, please also observe the following documents:
• User Manual “C7000 Controller for EC Tower” (ECD/U 091, 181, 251 (version 07), ECD/U 502 (version
03 or later))
• Technical Manual for outdoor unit
• Circuit diagram (supplied with the air conditioning unit on delivery
• Start-up report for EC Tower (for ECD/U 091, 181, 251 (version 07))
• Technical Manual for WIB 8000
• Repeated inspection: according to EN 378
The operator is responsible for the execution.
The operator must ensure that all maintenance, inspection and assembly work is carried out by authorised
and qualified specialist staff who have made an in-depth study of the operating instructions.
It is absolutely essential to comply with the procedure for shutting down the system described in the operating
instructions. Before maintenance work, the unit must be switched off at the main switch and a warning sign
displayed to prevent unintentional switching-on.
Unacceptable operating methods
The operating safety of the system is only guaranteed when it is used as intended. The limit values stipulated
in the technical data must not be exceeded under any circumstances.

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3. Residual risks
Transport, Installation
Area Cause Danger Safety instructions
Under the unit Faulty lifting equipment Crushing Do not remain under the unit
Next to the unit Floor or raised floor stand
is uneven or not adequate
for the weight
The unit could fall over and
crush somebody
Make sure that the floor is even and firm, and
the raised floor stand is correctly constructed.
Wear personal protective equipment (helmet,
gloves, safety boots).
In the lower part of
the unit
Heat from soldering flame,
sharp edges, parts
Burns,
cuts, knocks
Wear goggles and protective gloves, do not
insert your head into the unit.
Junction boxes 1
and 2
Voltage from connecting
cable, sharp edges on
cable entries
Electric shock, damage to
cable during routing
Check that power is disconnected, and fuse.
Stand on an insulated surface. Make sure that
sharp edges are always protected by rubber
grommets.
Start-up
Area Cause Danger Safety instructions
In the lower part of
the unit, refrigerant
pipework
Faulty refrigerant filling
pipe, leaky refrigerant
pipes, closed stop valves,
faulty safety valve
Refrigerant escaping at high pressure,
burns on contact with the skin, formati-
on of acid fumes near open flames
Open stop valves.
Wear goggles and protective
gloves, do not insert your head into
the unit.
Fan Fan runs on after air con-
ditioning unit has been
switched off.
Loss of limbs. Wait until the fan has come to a
stop before opening the air condi-
tioning unit.
Fan blower outlet in
Upflow units
Small parts that have fal-
len into the fan
Small parts can be hurled out of the fan
when the unit is started.
Inspect the fan for small parts
before switching on.
Do not stand over the blower
outlet.
Junction boxes 1
and 2
Short-circuit Flashover, caustic fumes Tighten clamped connections,
wear protective gloves.

11© STULZ GmbH – all rights reserved EN/01.2019/G22
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Operation
Area Cause Danger Safety instructions
In the lower part of
the unit, refrigerant
pipework
Leaky refrigerant pipes,
faulty safety valve, faulty
high-pressure switch, fire
Refrigerant escaping at high pressure,
exploding sections of pipe, formation of
acid fumes near open flames
Wear a respiratory mask in the
event of fire.
Floor of unit, raised
floor
Banked up condensate
and escaping water due to
excessively small or blo-
cked drainage pipe
Corrosion and mold formation due to
humidity.
Moisture and electrical connections.
Switch off power to the area where
water is exiting.
Electrical supply cable Wrong cable sizes, pro-
tective equipment
Short-circuit, fire, caustic fumes Route supply cables and protective
equipment correctly. Wear a respi-
ratory mask.
Maintenance
Area Cause Danger Safety instructions
In the lower part of
the unit, refrigerant
pipework
Leaky refrigerant pipes,
faulty safety valve, faulty
high-pressure switch
Refrigerant escaping at high pressure,
burns on contact with the skin, formati-
on of acid fumes near open flames
Wear goggles and protective
gloves, do not insert your head into
the unit.
Heater behind the
heat exchanger
Heat Burns on contact with the skin Wear protective gloves. Avoid con-
tact with hot parts of the unit.
Heat exchanger Sharp edges, fins Cuts Wear protective gloves.
Steam humidifier Escaping steam Burns Avoid the area near the steam
lance.
Junction boxes 1
and 2
Components that appear
safe may be live.
Electric shock Secure master switch so it cannot
be switched on.
Fan Fan runs on after air con-
ditioning unit has been
switched off.
Loss of limbs. Wait until the fan has come to a
stop before opening the air condi-
tioning unit.
Fan blower outlet in
Upflow units
Small parts that have fallen
into the fan
Small parts can be hurled out of the fan
when the unit is started.
Inspect the fan for small parts
before switching on. Do not stand
over the blower outlet.
Dismantling
Area Cause Danger Safety instructions
In the lower part of
the unit, refrigerant
pipework
Detaching or disconnec-
ting refrigerant pipes under
pressure.
Refrigerant escaping at high pressure,
burns on contact with the skin.
Shut off pressure to lines before
disconnecting.
Wear goggles and protective
gloves, do not insert your head into
the unit.
Junction boxes 1
and 2
Voltage on electrical sup-
ply cable
Electric shock Check that supply cable is free
from voltage before removing,
wear protective gloves.

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4. Transport / Storage
4.1 Delivery of units
Stulz A/C units are mounted on pallets and packed several times in plastic film.
NOTE
The refrigerant circuit is filled with inert gas.
Construction of protective covering:
(from inside to outside)
The following information can be found
on the packing:
1.Neopolene cushioning
2.Shrink film
1)Stulz logo
2)Stulz order number
3)Type of unit
4)Packing piece - contents
5)Warning symbols
NOTICE
When delivery is accepted, check the unit against the consignment papers for completeness
and for external damage and record it on the consignment note in the presence of the freight
forwarder.
• You receive the consignment papers with the delivery of the A/C unit.
• The shipment is made ex works, in case of shipment damages, please assert your claim towards the
carrier.
4.2 Transport
DANGER
Mortal danger by crushing
A defective lifting device can lead to the uncontrolled fall of the A/C unit.
Do not stay under suspended loads!
The Stulz A/C units can be moved by lifting devices with belts or ropes.
• x the belts or ropes at the pallet,
• protect the upper unit edges by wooden laths or metal brackets in such a way that they could not be caved
in.

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NOTICE
Risk of distorting the frame
Never move the unit on rollers and never transport it on a fork lift without pallet.
4.3 Storage
If you put the unit into intermediate storage before the installation, the following measures have to be carried
out to protect the unit from damage and corrosion:
• the storage point must not be exposed to direct sunlight. Observe the storage conditions in the chapter
“Application limits“.
• store the unit packaged to avoid the risk of corrosion.
You can move the unit still packaged on the pallet with a fork lift truck.
• take care that the centre of gravity is within the fork surface.
• take care that the unit is in an upright position at the transport.

14
EC = EC Tower
D = Downflow
U = Upflow
Typenschild/type plate
plaque d’appareil
S. Nr.
s.-no.
no. serie
Lieferant
manufacturer
vendeur
STULZ GmbH Hamburg
Holsteiner Chaussee 283, D22457 Hamburg
Made in Germany
Typ
type
type
EC TOWER 181D
Artikel-Nr.
Item-no.
numéro d’article
B72040
Kältemittel
refrigerant
frigorigène
Kommission/Alt
commission/alt
commission/alt
0530111234/07
Baujahr
model
modele
2019
Versorgunsspannung
supply voltage
tension de service
400
50
V ± 10%
Hz± 1%
Max. Betriebsdruck
max. operation pressure
pression de fonction max.
41.5 bar
Max. Füllgewicht
max. filling charge
charge max. de rempliss.
––– kg
E D 1C 18
R410A
EN/01.2019/G22 © STULZ GmbH – all rights reserved
EC TOWER TECHNICAL MANUAL
5. Description
5.1 Type code
The type code represents the unit variant of your A/C unit and can be found on the rating plate. The
rating plate is located in the door in front of the electrical compartment.
internal part no.
Order number
+ alternative
Serial no.
Unit type
Page code
Explanation
Unit variants
Product range
Airflow direction
Number of refrigeration circuits
Model size of unit
Date of issue
month/year
Language:
EN = English
Index number
Manufacturing base:
G = Germany
C = China
I = Italy
EN/01.2019/G22

15© STULZ GmbH – all rights reserved EN/01.2019/G22
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5.2 Proper use
The EC Tower is used to regulate the room temperature and air humidity and is intended for indoor installation.
The EC Tower is designed for removing high heat loads from 150 to 700 W/m² from small and medium-sized
equipment rooms.
Any other use beyond the above is regarded as improper use. Stulz cannot be held liable for damage resulting
from such use. The plant operator is the sole bearer of this risk.
5.3 Improper use
The EC Tower must not be used in areas:
• at risk of explosion
• with aggressive, acidic or alkaline fumes
• with very salty air, such as directly on the coast
• with a risk of strong radioactivity
• that are very dusty
• where people are indoors in the immediate vicinity of the unit for long periods.
The EC Tower is not suitable for continuous dehumidifying.

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EC TOWER TECHNICAL MANUAL
ECD 91 - Front
Steam cylinder
Steam nozzle
5.4 EC Tower method of operation
Temp./humidity
sensor B01
Electric heater
Steam cylinder (detailed view)
Stop valves
Junction box 2:
For communication with the
outdoor unit
Fan
Air filter
Junction box 1
The unit described here is the indoor unit of an air conditioning system. The main components of the indoor
unit are a fan, a heat exchanger and an electric heater.
The unit is operated solely via the C7000AT controller in the front panel and the master switch in junction box
1. The air inlet contains a temperature/humidity sensor, which supplies the measured values for temperature
and humidity control. Cooling is achieved in compressor mode, in combination with the outdoor unit.
The EC Tower is controlled by the integrated C7000 I/O controller. The operating strategy allows a total of
10 EC Towers to be controlled from a single unit. In all, 20 users (10 C7000AT controllers and 10 C7000 I/O
controllers) can be integrated in the bus.
The EC Towers can be installed individually, although in this case the control line must not exceed the maxi-
mum overall length of 1000 m.
Dehumidification
Dehumidification is achieved by lowering the speed of the fan. At a constant cooling capacity, the temperature
of the air flowing through the heat exchanger drops below dew point. The humidity in the air condenses on the
heat exchanger, collects in the condensate tray and is discharged via the condensate drain.

17© STULZ GmbH – all rights reserved EN/01.2019/G22
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ECD 181/251 - Front
Stop valves
Fan
Air filter
Electric heater
Steam cylinder
Steam nozzle
Temp./humidity
sensor B01
Steam cylinder (detailed view)
Junction box 2:
For communication with the
outdoor unit
Junction box 1

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ECU 91 - Front ECU 91 - Rear
ECU 181/251 - Front ECU 181/251 - Rear
Stop valve
Junction box 2
Junction box 2:
For communication with the
outdoor unit
Temp./humidity sensor B01
Electric heater
Fan
Stop valve
Junction box 2:
Junction box 2:
For communication
with the outdoor
unit
Fan
Junction box 1
Temp./humidity sensor B01
Steam cylinder
Hose
Steam lance
Steam lance
Steam cylinder
(detailed view)
Electric heater
Fan
Junction box 1
Steam cylinder
Hose
Steam lance
Steam humidifier
(detailed view)

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THIR1THIR2
Gas line
Heat exchanger
THIA
THIR3
Injection line
Detailed view: Interior of EC Tower
Sensors in the EC Tower
The detailed view from the interior of the EC Tower shows the names and locations of sensors used in the EC
Tower. The table describes the function of these sensors.
The steam humidifier starts up if the humidity setpoint, including start value, is exceeded. The C7000AT and CPY
controllers regulate the steam production of the steam humidifier. It is controlled proportionally via a 010 V signal.
The steam humidifier is described in the following section:
• Section “14.2 Steam humidifier OEM User Manual“ on page 164.
Setting the steam humidifier on the C7000AT is described in the following manual:
• User Manual “C7000 Controller for EC Tower”.
Steam cylinder
Hose
Steam lance
Steam cylinder
Steam nozzle
Steam humidifier
The EC Tower is factory-fitted with a steam humidifier. The diagrams below show the components of the
steam humidifier in the Upflow and Downflow units.
Steam humidifier in Upflow units Steam humidifier in Downflow units
Sensor Location Function
THIR1 Surface of heat
exchanger Overheating and frost
protection
THIR2 Injection line
THIR3 Gas line Overheating protection
THIA Interior of EC Tower No switching or techni-
cal function
B01 Return air duct of EC
Tower
Temperature/humidity
sensor

20 EN/01.2019/G22 © STULZ GmbH – all rights reserved
EC TOWER TECHNICAL MANUAL
Upflow ECU 91, 181, 251
5.5 EC Tower sizes and versions
5.5.1 Sizes
Downflow ECD 91, 181, 251
The unit is available in three sizes:
• Size 1 includes the ECD/U 91 Downow and Upow units:
- ECD/U 91 version 07: Produced from 01/2018
• Size 2 includes the ECD/U 181 and ECD/U 251 Downow and Upow units:
- ECD/U 181 and 251 version 07: Produced from 01/2018
• Size 3 includes the ECD/U 502 Downow and Upow units:
- ECD/U 502 version 01: Prototype; version 02: Produced from 05.2017, version 03: Produced from
01.04.2018
This Technical Manual describes sizes 1 and 2. Size 3 is described in another Technical Manual.
5.5.2 Unit versions
In Upflow units, the warm air is sucked into the front of the indoor unit. The cold air is blown out upwards or
horizontally via the optional air blow-out plenum.
In Downflow units, the warm air is sucked into the top of the indoor unit. The cold air is blown out downward
into the raised floor or into the blow-out plinth.