Bosch Compress Hybrid 3400i AW User manual

6721861825 (2023/08) en
Installation Instructions
Indoor unit for air to water heat pumps
Compress Hybrid 3400i AW
0010038889-001
HC3400iAW 8 l

Table of contents
Compress Hybrid 3400i AW – 6721861825 (2023/08)
2
Table of contents
1 Explanation of symbols and safety instructions . . . . . . . . . . . 3
1.1 Explanation of symbols . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 General safety instructions . . . . . . . . . . . . . . . . . . . . . . . 3
2 Product description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 GB Importer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2 Scope of delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3 Product overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.4 Possible combinations of indoor and outdoor
units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.5 Possible combinations of indoor unit and external
booster heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.6 Dimensions and minimum clearances . . . . . . . . . . . . . . 6
3 Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4 Preparing for installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.1 Water quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.2 Install the particulate filter. . . . . . . . . . . . . . . . . . . . . . . . 8
4.3 Heating system minimum volume and flow . . . . . . . . . . 8
4.4 Installing the piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.5 Installing the pressure-relief valve. . . . . . . . . . . . . . . . . . 9
4.6 Installing the heating pump (optional) . . . . . . . . . . . . . . 9
4.7 Maximum sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.8 Insulating the hydraulic pipework . . . . . . . . . . . . . . . . . 10
5 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1 Transport and storage . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.2 Unpacking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.3 Indoor unit installation. . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.3.1 Removing the cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.3.2 Installing the indoor unit . . . . . . . . . . . . . . . . . . . . . . . . 11
5.3.3 Fitting the cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.4 Connecting the indoor unit to the outdoor unit . . . . . . 13
5.5 Connecting the indoor unit to the external booster
heater and heating system. . . . . . . . . . . . . . . . . . . . . . . 16
5.6 Fitting the outside temperature sensor . . . . . . . . . . . . 17
5.7 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.7.1 Mounting the flow temperature sensor. . . . . . . . . . . . . 17
5.7.2 Installing the heating circuit module. . . . . . . . . . . . . . . 17
5.7.3 Room temperature-dependent controller . . . . . . . . . . 17
5.7.4 Installing the accessories for the cooling mode . . . . . . 17
5.7.5 Installation with swimming pool . . . . . . . . . . . . . . . . . . 18
5.7.6 Connect-Key K 30 RF . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6 Electrical connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.1 Connecting the device . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.2 Routing cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.3 Connecting the power supply . . . . . . . . . . . . . . . . . . . . 20
6.4 CAN-BUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.5 Installation of the temperature sensor . . . . . . . . . . . . . 21
6.6 Connecting the outside temperature sensor . . . . . . . . 21
6.7 External booster heater (uncommon in UK market) . . . . 22
6.7.1 Connect the actuator of the external booster
heater (e.g. floor standing boiler). . . . . . . . . . . . . . . . . 22
6.7.2 Connect the alarm signal for the external booster
heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.7.3 Solenoid valve for external auxiliary heater with
volume control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.8 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.8.1 EMS BUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.8.2 Connect the flow temperature sensor . . . . . . . . . . . . . 25
6.8.3 Connecting the heating circuit module. . . . . . . . . . . . . 26
6.8.4 Room temperature-dependent controller . . . . . . . . . . 26
6.8.5 Connecting the dew point monitor . . . . . . . . . . . . . . . . 26
6.8.6 Connecting the swimming pool mixer . . . . . . . . . . . . . 26
6.8.7 Connecting MB LAN 2 . . . . . . . . . . . . . . . . . . . . . . . . . . 26
6.8.8 External connections. . . . . . . . . . . . . . . . . . . . . . . . . . . 27
7 Commissioning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
7.1 Filling and venting the heating system . . . . . . . . . . . . . 27
7.2 Operation without outdoor unit (Stand-alone
mode and chimney sweep mode). . . . . . . . . . . . . . . . . 27
7.3 Function test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
7.3.1 Operating temperatures . . . . . . . . . . . . . . . . . . . . . . . . 27
8 Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
8.1 Overview of control elements and symbols . . . . . . . . . 28
8.2 Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
8.3 General commissioning of the user interface . . . . . . . 30
8.4 System handover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8.5 Service menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8.5.1 Menu: Set additional heater . . . . . . . . . . . . . . . . . . . . . 30
8.5.2 Menu: Auxiliary heater with mixer. . . . . . . . . . . . . . . . . 30
8.6 Cooling mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
8.7 Adjusting the room temperature-dependent
controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
9 Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
9.1 Draining the heating system . . . . . . . . . . . . . . . . . . . . . 31
9.2 Replacing components . . . . . . . . . . . . . . . . . . . . . . . . . 31
9.2.1 Replacing the pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
9.2.2 Replacing the temperature sensor . . . . . . . . . . . . . . . . 32
10 Environmental protection and disposal . . . . . . . . . . . . . . . . . 33
11 Data Protection Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
12 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
12.1 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
12.2 Hydraulic diagram of the indoor unit . . . . . . . . . . . . . . 35
12.3 System solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
12.4 Installer module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
12.5 System Commissioning Report. . . . . . . . . . . . . . . . . . . 41
12.6 Error codes on the display. . . . . . . . . . . . . . . . . . . . . . . 43

Explanation of symbols and safety instructions
3
Compress Hybrid 3400i AW – 6721861825 (2023/08)
1 Explanation of symbols and safety instructions
1.1 Explanation of symbols
Warnings
In warnings, signal words at the beginning of a warning are used to
indicate the type and seriousness of the ensuing risk if measures for
minimizing danger are not taken.
The following signal words are defined and can be used in this document:
DANGER
DANGER indicates that severe or life-threatening personal injury will
occur.
WARNING
WARNING indicates that severe to life-threatening personal injury may
occur.
CAUTION
CAUTION indicates that minor to medium personal injury may occur.
NOTICE
NOTICE indicates that material damage may occur.
Important information
The info symbol indicates important informationwhere there is no risk to
people or property.
Additional symbols
Table 1
Table 2
1.2 General safety instructions
HNotices for the target group
These installation instructions are intended for gas, plumbing, heating
and electrical contractors. All instructions must be observed. Failure to
comply with instructions may result in material damage and personal
injury, including danger to life.
▶ Read the installation, service and commissioning instructions (heat
source, heating controller, pumps, etc.) before installation.
▶ Observe the safety instructions and warnings.
▶ Follow national and regional regulations, technical regulations and
guidelines.
▶ Record all work carried out.
HIntended use
This product is intended for use in sealed heating systems in residential
buildings.
Anyotheruseis considered as notintended.Liabilitywillnotbe assumed
for any resulting damage.
Handling refrigerant
Refrigerant R32 is used in the system.
▶ Only qualified and authorised refrigerant circuit engineers may work
on the refrigerant circuit.
▶ Always wear suitable protective gloves and goggles when working
with refrigerant.
HWhat to do if refrigerant leaks
If refrigerant leaks and touches the skin, it can cause frostbite.
▶ In case of a refrigerant leak, never touch any components of the air to
water outdoor unit.
▶ Avoid skin or eye contact with refrigerant.
▶ Seek medical attention if you get refrigerant on your skin or in your
eyes.
▶ If the refrigerant leaks please contact your installer immediately.
HInstallation, maintenance and repairs
Installation, maintenance and repairs must only be carried out by an
approved contractor.
Asuitable qualificationisrequired,especiallywhen workingon electrical
parts or on the refrigerant circuit.
▶ Do not repair, manipulate or deactivate safety-relevant components.
▶ Only install original spare parts.
HCommissioning
Commissioning must only be carried out by the service engineer of the
manufacturer or the installer.
HElectrical work
Electrical work must only be carried out by electrical installation
contractors.
Before starting electrical work:
▶ Isolate all poles of the mains voltage and secure against
reconnection.
▶ Make sure the main voltage is disconnected.
▶ Before touching live parts: Wait at least 5 minutes to discharge the
capacitors.
▶ Observe the wiring diagrams of other system components as well.
Symbol Meaning
▶ a step in an action sequence
a reference to a related part in the document
• a list entry
–a list entry (second level)
Symbol Meaning
Warning of strong magnetic field.
Maintenance by a qualified person should be done
while following the instructions of the service manual.
For operation follow the instructions of the user
manual.

Product description
Compress Hybrid 3400i AW – 6721861825 (2023/08)
4
HEstablishing the connection to the power supply
A device that safely isolates the appliance from the power supply must
be used.
▶ Install a safety switch that disconnects all poles from the power
supply.
HPower cable
To avoid danger, have damaged power cables replaced by the
manufacturer, a Service engineer authorised by the manufacturer or by
other qualified personnel.
HHandover to the user
When handing over, instruct the user how to operate the heating system
and inform the user about its operating conditions.
▶ Explain how to operate the heating system and draw the user's
attention to any safety relevant action.
▶ In particular, point out the following:
– Alterations and repairs must only be carried out by an approved
contractor.
– Safe and environmentally compatible operation requires
inspection at least once a year and responsive cleaning and
maintenance.
– The heat generator may only be operated with the casing fitted
and closed.
▶ Point out the possible consequences (personal injury, including
danger to life or material damage) of non-existent or improper
inspection, cleaning and maintenance.
▶ Point out the dangers of carbon monoxide (CO) and recommend the
use of CO detectors.
▶ Leavetheinstallation instructions andthe operatinginstructionswith
the user for safekeeping.
HNotice on operation
Operate the appliance only with mounted and closed casing.
2 Product description
2.1 GB Importer
Bosch Thermotechnology Ltd.
Cotswold Way, Warndon
Worcester WR4 9SW / UK
2.2 Scope of delivery
▶ Upon delivery, check whether the packaging is intact.
▶ Check the scope of delivery for completeness:
–Indoorunit
– Documentation
– Drilling template
– Cable feeds
– Mounting rail
– Bag with terminals
– Bag with screws
– Outside temperature sensor
– Pressure-relief valve and corresponding connections
– Clamping ring fitting
2.3 Product overview
Fig. 1 Components and pipe connections of the indoor unit
[1] Automatic air vent
[2] Installer module
[3] Relay box
[4] Mixing valve
[5] DHW circulation pump (heat transfer medium)
0010029907-004
1
2
4
5
3

Product description
5
Compress Hybrid 3400i AW – 6721861825 (2023/08)
Fig. 2 Components and ppipe connections of the indoor unit (shown
without electronic components)
[1] Condenser
[2] Low-loss header
[3] Mixing valve
Fig. 3 Bottom view of the indoor unit
[1] Return to outdoor unit
[2] Flow from the outdoor unit
[3] Return to external booster heater
[4] Flow to heating system
[5] Return from the heating system
[6] Flow from external booster heater
[7] Front of appliance
2.4 Possible combinations of indoor and outdoor units
The indoor unit is intended for installation inside the building and for
connection to heat pump outdoor units installed in the open air.
The indoor unit can be used with the following outdoor units:
• CS3400iAW 4 OR-S (ODU Split 4 kW)
• CS3400iAW 6 OR-S (ODU Split 6 kW)
• CS3400iAW 8 OR-S (ODU Split 8 kW)
2.5 Possible combinations of indoor unit and external
booster heater
The indoor unit can be operated in combination with a gas condensing
appliance, providing the gas condensing appliance satisfies the
following minimum requirements:
• Minimum modulation: factor 4
• Maximum output: 32 kW
• Integrated heating pump
• Free analogue (0 – 10 V) or digital (On/Off) input (Chapter 6.7)
If the indoor unit is to be operated without a gas condensing appliance,
additional safety equipment must be installed in the heating system in
compliance with the applicable standards and guidelines.
Single-stage boiler (not modulating), e.g. wall mounted oil condensing
boiler may only be used if they are smaller or dimensioned according to
the heating load of the building (not dimensioned to continuous DHW
output, only exclusively to the building heating load). The additional
coverage of the heating load via the heat pump must be considered.
Overdimensioning must be ruled out in order to avoid a excess and
impermissible cycling of the boiler.
DHW is only provided via the external booster heater (combi boiler)
(Fig. 23)
0010029893-003
2
3
1
0010029912-003
1
2
3
4
5 6 7

Regulations
Compress Hybrid 3400i AW – 6721861825 (2023/08)
6
2.6 Dimensions and minimum clearances
Mount the indoor unit high enough so that the control unit is easy to use.
In addition, take into account pipes and connections under the indoor
unit.
Fig. 5 Clearances between connections (mm)
3Regulations
Follow the directives and regulations given below:
• Local provisions and regulations of the electricity supplier and
corresponding special rules
• National building regulations
•F-Gas regulation
•EN 50160 (Voltage characteristics of electricity supplied by public
electricity networks)
•EN 12828 (Heating systems in buildings - Design and installation of
water-based heating systems)
•EN 1717 (Protection of potable water against pollution in potable
water installations)
•EN 378 (Refrigerating systems and heat pumps - Safety and
environmental requirements)
• Local installation regulations for low-voltage electrical installations,
e.g. DIN VDE 0100 (for Germany) or IEC 60364
The document 6720807972 contains further information about the
applicable regulations. You can use the document search on our website
to display this. You will find the address of the website on the back of
these instructions.
0010029918-003
350
90 129
100627066
243
62 114
9844
67
Fig. 4 Minimum distance (mm)
[A] It is recommended to ensure a minimum volume of 1 m³ underneath
the indoor unit. If this is not possible, ensure that the room is not
air-tight by allowing an air vent passage at a height lower than the
bottom of the indoor unit.
0010028013-005
≥100 ≥100
≥550
A
≥800
655
757

Preparing for installation
7
Compress Hybrid 3400i AW – 6721861825 (2023/08)
4 Preparing for installation
NOTICE
Residue in the pipework can damage the system.
Residue and particles in the heating system impair the flow rate and lead
to faults.
▶ Before connecting the indoor unit, flush the pipe system to remove
any foreign bodies.
4.1 Water quality
Water quality in the heating system
Heat pumps operate at lower temperatures than other heating systems
which means that the thermal de-airing is not as effective and oxygen
levels are never as low as with a system incorporating an electric/oil/ gas
boiler. This means that the heating system will be more susceptible to
corrosion when exposed to aggressive water.
Preventive actions are required if the heating system require recurrent
filling or where a heating water sample don’t show clear water.
Preventive actions can be to supplement the heating system with a
magnetite filter and a de-airing valve.
Actions when the heating system requires recurrent filling:
▶ Check that the volume of the expansion vessel is sufficient to the
heating system volume.
▶ Replace the expansion vessel.
▶ Check the heating system for leaks.
A systemseparation with the help of a heat exchanger may be required if
the limits in table 3 can not be achieved.
Do not use any water additives except for a non-toxic pH-enhancer
and keep the water clean.
The limits stated in table 3 are required to ensure the output data and
operation of the heat pump throughout its entire service life.
Table 3 Water quality
Additional water treatment to prevent lime-scale deposits
A poor quality of the heating water promotes the formation of sludge and
lime-scale. This can lead to malfunctions and damage of the heat
exchanger in the heat pump. According to the current guideline VDI
2035 “Prevention of damage in water heating installations” and
depending on the degree of hardness of the filling water, the system
volume and the total output of the system, water treatment may be
required to avoid damage due to the formation of lime-scale.
If the limits for water hardness stated in table 3 are exceeded, the
performance of the heat pump will deteriorate over time. If this
performance degradation can be accepted, the limits in figure 1 are
required to ensure the operation of the heat pump throughout its entire
service life.
Table 4 Table for heat pumps
Fig. 6 Limits for water treatment in heat pump systems
A Use completely de-mineralized fill water above the curve,
conductivity ≤ 10 microsiemens /cm.
B Use untreated tap water below the curve. Fill according to the
drinking water regulation.
HwWater hardness.
V Total water volume: fill volume of the heating system and top-up
volume over the service life of the heat pump.
Ifthe totalwatervolumeis abovethelimit curvein thediagram (Fig. 6)
suitable measures are required for water treatment.
Suitable measures are:
• Use of fully de-mineralized fill water with a conductivity of ≤ 10
microsiemens / cm.
To prevent oxygen from entering the heating water, the expansion vessel
must be adequately dimensioned.
When installing diffusion open pipes, a system separation with the help
of a heat exchanger is required.
Water treatment products
NOTICE
Material damage due to contamination in the system!
Dirt particles from the system can damage the unit and impair efficiency.
▶ Observe instructions of the guideline BS7593 for the treatment of
water in warm water treatment systems.
▶ Do not use frost protection/glycol products.
Water quality
Hardness <3 °dH
Oxygen content <1 mg/l
Carbon dioxide, CO2<1 mg/l
Chloride ions, CL-<250 mg/l
Sulphate, SO4<100 mg/l
Conductivity <350 μS/cm
pH 7,5 – 9
Heat pump
output [kW]
Total alkalinity
/totalhardness
of the filling
water [°dh]
Maximum fill and top-up water
volume Vmax [m3]
Q< 50 Requirements
according to
figure 6
Requirements according to
figure 6
0,00
0,20
0,40
0,60
0,80
1,00
1,20
1,40
1,60
1,80
2,00
2,20
2,40
2,60
0 5 10 15
0010036248-002
V [m
3
]
H
W
[°dH]
A
B

Preparing for installation
Compress Hybrid 3400i AW – 6721861825 (2023/08)
8
Suitable water treatment products (inhibitors/cleaning agent) are
available from the following manufacturers:
Table 5
4.2 Install the particulate filter
NOTICE
Pollution in the heating system may damage the indoor unit!
Dirt and pollution in the heating system may damage the indoor unit.
▶ Install a particulate filter in the heating return of the indoor unit.
The particulate filter must have the following characteristics:
• Mesh size: max. 0.6 mm
•Flowfactork
vs: minimum 7 m³/h
•Magnetiteseparator
4.3 Heating system minimum volume and flow
A sufficient amount of energy stored in the system is required to avoid
multiple start/stop cycles, incomplete defrosting or unnecessary
alarms. Energy is stored in the heating system water volume, as well as in
the system components (radiators and underfloor heating).
For the defrost operation of the outdoor unit, a minimum volume and
flow must be ensured and permanently available.
The minimum volume can be provided by the open circuits (the
necessary zonevalves/thermostatsmust bealwaysfullyopen) and/orby
a buffer tank. For an optimal and most efficient defrost operation a
recommended volume is stated.
The minimum flow must be ensured within the minimum volume
available. If the minimum flow is not met, additional measures are
needed, e.g. differential bypass valve or parallel buffer. Note that if an
hydraulic separator is present it requires an additional heating circuit
pump.
In certain circumstances depending on the available energy stored in the
system, the auxiliary heater may be used to ensure the complete defrost.
Table 6 Minimum volume and flow for outdoor unit CS3400iAW 4 OR-S
Table 7 Minimum volume and flow for outdoor unit CS3400iAW 6-8 OR-
S
4.4 Installing the piping
NOTICE
Danger of faults due to contaminants in pipework!
Solids, metal/plastic filings, flax and thread tape residue and similar
material can get stuck in pumps, valves and heat exchangers.
▶ Keep foreign bodies from entering the pipework.
▶ Do not leave pipe parts and connections directly on the ground.
▶ When deburring, make sure that no residue remains in the pipe.
CAUTION
Risk of injury due to refrigerant leakage!
Skin or eye contact with the refrigerant can cause frostbite. Risk of
suffocation due to inhalation of gases/vapours.
▶ Always wear suitable protective gloves and goggles when working
with refrigerant.
▶ Avoid skin or eye contact with the refrigerant.
▶ In case of skin or eye contact with the refrigerant, seek medical
attention.
▶ Do not inhale gases/vapours.
▶ Ensure sufficient ventilation at the workplace.
▶ Install refrigerant pipes between the outdoor unit and the indoor unit
according to the installation instructions of the outdoor unit.
▶Mount connection sets (accessories) on the pipe as shown in figure
7.
▶ Push the connector onto the pipe up to the catch.
▶ Tighten union nut using a suitable tool.
Fig. 7 Assembly of the clamping ring screw fitting
[1] Pipe
[2] Pipe socket cap
[3] Locking ring
[4] O-ring (black for hydraulics)
[5] Connection part
▶ Install piping for the heating system in the building up to the
installation location of the indoor unit.
▶ Install insulated piping between the outdoor unit and indoor unit,
keeping the length of the piping as short as possible.
ADEY 01242 546700
www.adey.com
FERNOX 0330 100 7750
www.fernox.com
SENTINEL 01928 704330
www.sentinelprotects.com/uk
Outdoor Unit CS3400iAW 4 OR-S
Minimum Recommended
Underfloor/fan coils 13l 35l
Radiators 4l 13l
Minimum flow 15l/min
Outdoor Unit CS3400iAW 6-8 OR-S
Minimum Recommended
Underfloor/fan coils 27l 40l
Radiators 10l 15l
Minimum flow 15l/min
0010036538-001
3
2
1
4
5

Preparing for installation
9
Compress Hybrid 3400i AW – 6721861825 (2023/08)
4.5 Installing the pressure-relief valve
▶ Install the pressure-relief valve in the flow outside the indoor unit.
▶ Ensure the pressure relief valve drain pip is not exposed to potential
freezing. Insulation may be required.
Fig. 8 Assembly of the pressure-relief valve
[1] Water pressure relief valve
[2] O-ring
[3] Pressure-relief valve connector pipe
[4] Retaining spring
[5] Gasket
4.6 Installing the heating pump (optional)
(Chapter 12.2, page 35)
Whether or not it is necessary to install a heating pump depends on the
configuration of the heating system and the amount of system
resistance.
▶ Select the heating pump based on the required pump flow rate and
pressure loss.
▶ Observe the minimum volumetric flow rate (Tab. 13, page 34).
▶ Install the bypass [1] between the flow [2]and return [3] (Fig. 9),
to hydraulically uncouple the heating pump from the heating circuit.
Observe the prescribed dimensions and clearances during assembly
(Tab. 8).
Table 8 Pipe diameter and bypass lengths
Fig. 9 Indoor unit with heating circuit and bypass
[1] By-pass
[2] Flow
[3] Return
Fig. 10 Detailed view of bypass
[L] Minimum bypass length
[D] Pipe diameter
Fig. 11 By-pass
[A] Bypass, straight design
[B] Bypass, U-shaped design (total length including the elbow)
4.7 Maximum sensor
In some countries a high limit safety cut-out is required in underfloor
heating circuits.
▶ Observe country-specific regulations.
▶ Establish connection as described in chapter 6.
Dimensions/clearances Unit Value
External diameter D mm 22
Minimum bypass length L
• Straight version A
• U-shaped version B
mm
mm
200
100
Maximum clearance
between bypass and
indoor unit
m1.5
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2
3
4
5
1.
2.
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Compress Hybrid 3400i AW – 6721861825 (2023/08)
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4.8 Insulating the hydraulic pipework
Insulating the pipework inside the building
CAUTION
Risk of burning!
Contact with uninsulated piping can inflict burns to the skin.
▶ Insulate all heat-conducting pipework using suitable thermal
insulation according to applicable regulations.
Insulating the pipework outside the building
NOTICE
Material damage from frost!
In case of a power outage the water in the hydraulic pipework may freeze.
▶ Use insulation with a thickness of at least 19 mm for pipework
outdoors.
▶ Use insulation with a thickness of at least 12 mm for pipework
indoors.
5 Installation
5.1 Transport and storage
The indoor unit must always be transported in its packaging and stored
in an upright position. The indoor unit can be provisionally tilted for
transportation purposes if required.
After unpacking the indoor unit, do not place or set it down on the pipes
or on the side panel.
▶ After unpacking the indoor unit, lay it down on the back panel.
Do not store or transport the indoor unit at temperatures below
– 10 °C.
5.2 Unpacking
▶ Remove the packaging according to the instructions on the
packaging.
▶ Take out enclosed accessories.
▶ Check that all package contents are present.
5.3 Indoor unit installation
5.3.1 Removing the cover
To unlock the cover [1]:
▶ Unscrew the unlocking screw [2] on the underside of the indoor unit
using a suitable tool.
Fig. 12 Unlock the cover
[1] Cover of the indoor unit
[2] Unlocking screw
To detach the cover [2] from the bottom fixing [1]:
▶ Pull the cover [2] on the underside slightly forwards.
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Compress Hybrid 3400i AW – 6721861825 (2023/08)
Fig. 13 Detach the cover from the bottom fixing
[1] Fixing on the underside
[2] Cover of the indoor unit
To detach the cover [2] from the top fixing [1]:
▶ Push the cover [2] slightly up.
Fig. 14 Detach the cover from the top fixing
[1] Fixing on the top side
[2] Cover of the indoor unit
NOTICE
Material damage due to tensile forces on the EMS cable!
The control unit in the cover is connected to the installer module via the
EMS cable.
▶ Pay attention tothe length of the EMS cable when removing the cover.
To remove the cover [1]:
▶ Pull the sides of the cover [1] slightly apart at the back (paying
attention to the top cover) and pull the cover forwards.
▶ Detach the EMS cable from the [2] control unit.
Fig. 15 Removing the cover
[1] Cover of the indoor unit
[2] Control unit
5.3.2 Installing the indoor unit
Specifications:
• The pipework between the outdoor unit heat pump and the indoor
unit must be as short as possible.
CAUTION
Risk of injury and material damage due to unsuitable fixing
components!
If the fixing components used are unsuitable for the existing wall
construction material, a permanent fixing cannot be guaranteed.
The supplied wall plug is suitable for standard masonry and concrete.
▶ Use wall plugs that are suitable for the wall construction material.
▶ Install the mounting rail (scope of delivery) on a suitable wall using
the drilling template (Chapter 2.6).
▶ Hang the indoor unit centrally onto the mounting rail (Fig. 16).
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Fig. 16 Hanging the indoor unit
▶ Insulate the pipework (Chapter 4.8).
5.3.3 Fitting the cover
To fit the top cover [1]:
▶ Connect the EMS cable to the control unit [2].
▶ Pull the sides of the cover [1] slightly apart at the back (paying
attention to the top cover) and push the cover backwards.
Fig. 17 Fitting the cover
[1] Cover of the indoor unit
[2] Control unit
To attach the cover [2] to the top fixing [1]:
▶ Push the cover [2] slightly down.
Fig. 18 Attach the cover to the top fixing
[1] Fixing on the top side
[2] Cover of the indoor unit
00100
0010031293-002
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Compress Hybrid 3400i AW – 6721861825 (2023/08)
To attach the cover [2] to the bottom fixing [1]:
▶ Push the cover [2] on the underside slightly back.
Fig. 19 Attach the cover to the bottom fixing
[1] Fixing on the underside
[2] Cover of the indoor unit
To lock the cover [1]:
▶ Screw in the locking screw [2] on the underside of the indoor unit
using a suitable tool.
Fig. 20 Locking the cover
[1] Cover of the indoor unit
[2] Locking screw
5.4 Connecting the indoor unit to the outdoor unit
CAUTION
Risk of injury due to refrigerant leakage!
Skin or eye contact with the refrigerant can cause frostbite. Risk of
suffocation due to inhalation of gases/vapours.
▶ Always wear suitable protective gloves and goggles when working
with refrigerant.
▶ Avoid skin or eye contact with the refrigerant.
▶ In case of skin or eye contact with the refrigerant, seek medical
attention.
▶ Do not inhale gases/vapours.
▶ Ensure sufficient ventilation at the workplace.
NOTICE
Residue in the pipework can damage the system.
Solids, metal/plastic filings, flux and thread tape residue and similar
material can get stuck in pumps, valves and heat exchangers.
▶ Keep foreign bodies from entering the pipework.
▶ Do not leave pipe parts and connections directly on the ground.
▶ When deburring, make sure that no residue remains in the pipe.
▶ Before connecting the heat pump and indoor unit, rinse the pipe
system to remove any foreign bodies.
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NOTICE
Deformation due to heat!
If the temperature is too high, the insulation material in the indoor unit
deforms.
▶ Do not solder the piping to the indoor unit.
▶ Use clamp couplings to connect the pipes to the outdoor unit if
available.
▶ Size pipework as specified in the installation instructions for the
outdoor unit.
▶ Connect the refrigerant line of the outdoor unit to the refrigerant inlet
of the indoor unit.
▶ Connect the refrigerant line of the outdoor unit to the refrigerant
outlet of the indoor unit.
Fig. 21 Connecting the indoor unit to the outdoor unit (schematic representation)
[1] Refrigerant outlet
[2] Refrigerant inlet
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Compress Hybrid 3400i AW – 6721861825 (2023/08)
Pump curves
Fig. 22 Pump curves
p Pressure [kPa]
HHead[m]
Q Volumetric flow rate [m3/h]
P1 Electrical power input [W]
0010039375-001
0
1
2
3
4
0,0 0,4 0,8 1,2 1,6 2,0 2,4 2,8 3,2 3,6 4,0
H
[m]
Q [m3/h]
5
6
7
8
p
[kPa]
70
60
50
40
30
20
10
0
Q [l/s]
0,0 0,2 0,4 0,6 0,8 1,0 1,2
0
10
20
30
40
P1
[W]
50
60
70
0,0 0,4 0,8 1,2 1,6 2,0 2,4 2,8 3,2 3,6 4,0 Q [m3/h]

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5.5 Connecting the indoor unit to the external booster
heater and heating system
NOTICE
Deformation due to heat!
If the temperature is too high, the insulation material in the indoor unit
deforms.
▶ Do not solder the piping to the indoor unit.
▶ Use clamp couplings to connect the pipes to the outdoor unit if
available.
NOTICE
Risk of material damage due to leaking connections!
Mechanical stresses in connecting pipework can result in leaks.
▶ Install connecting pipework without mechanical stresses at the
connections on the boiler.
▶ Ensure that all connections are tight.
Establish the following connections at the indoor unit:
• Connect the return [3] from the heating system with particulate filter
[1].
• Connect the flow [2] to the heating system.
• Connect the pipework from the external booster heater [4].
• Connect the pipework to the external booster heater [5].
• Route a drain hose on a slope to a frost-free drain.
Fig. 23 Connection of the indoor unit to the heating system and the booster heater (example representation with bypass and additional heating pump)
[1] Particle filter
[2] Flow to heating system
[3] Return from the heating system
[4] Flow to the auxiliary heater
[5] Return to the auxiliary heater
[6] DHW connection (combi boiler)
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Compress Hybrid 3400i AW – 6721861825 (2023/08)
5.6 Fitting the outside temperature sensor
If the length of the temperature sensor cable outdoors is more than
15 m:
▶ Use screened cable.
Atemperaturesensor cablethat runs outdoorsmust satisfy thefollowing
requirements:
• Cable diameter: 0.5 mm2
• Resistance: max. 50 Ohm/km
•Numberofconductors:2
• Maximum length: 50 m
▶ Mount the sensor on the coldest side of the house (normally facing
north).
– Protect the sensor from direct solar radiation, draughts, etc.
– In addition, the sensor must not be installed directly under the
ceiling.
Fig. 24 Positioning the outside temperature sensor
5.7 Accessories
5.7.1 Mounting the flow temperature sensor
The installation of the flow temperature sensor T0 depends on the
design of the heating system.
No additional measures are required when the heating system is not
equipped with a buffer cylinder or low loss header as the flow
temperature sensor is already integrated into the indoor unit.
If the heating system is equipped with a buffer cylinder:
▶ Install the flow temperature sensor T0 at the buffer cylinder.
▶ Electrical power connection (Chapter 6.8.2).
Assembly downstream of the bypass or at the buffer cylinder
If the flow temperature sensor is installed outside the indoor unit on the
buffer cylinder or downstream of the bypass (e.g. when using a heating
circuit set), it must be removed from the indoor unit and extended using
a suitable extension cable of corresponding length (H03VV-F
2x0.5 mm2) (Chapter 6.8.2).
5.7.2 Installing the heating circuit module
In the delivery scope a heating circuit without mixer can be controlled via
the controller.
If other heating circuits are to be installed, a heating circuit module is
required for each heating circuit.
▶ Install the heating circuit module, mixer, heating pump and other
components according to the selected system solution.
▶ Observe the relevant separate installation and operating instructions
when installing and adjusting the components.
▶ Electrical connection (Chapter 6.8.3).
5.7.3 Room temperature-dependent controller
In the default setting, the controller automatically regulates the flow
temperature depending on the outside temperature. A room
temperature-dependent controller can be installed for greater comfort.
▶ Electrical connection (Chapter 6.8.4).
5.7.4 Installing the accessories for the cooling mode
NOTICE
Damage to the indoor unit due to condensation
The indoor unit with mixer is not designed to be used in cooling mode
below the dew point.
▶ Only use the indoor unit in cooling mode above the dew point.
For cooling operation, the installation of a dew point monitor
(accessory) is absolutely essential.
▶ Install the dew point monitor on the flow pipe for the heating system
(Figure 25).
▶ Electrical connection (Chapter 6.8.5).
1/2H(min 2m)
H
N
S
WE
NW NE
SW SE
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Fig. 25 Dew point monitor position
[1] Dew point monitor with cable
[2] Plug, dew point monitor
Aprerequisite for usingthe heating system in cooling mode is that aroom
thermostat is installed in the heating system to prevent condensate
formation.
There are two installation options:
• Room thermostat with integrated dew point monitor sensor (CR10H
or ModuLine 1010H).
• Room thermostat (CR10 or ModuLine 1010) in combination with
dew point monitor sensor in the heating system.
Use of a CR10H or ModuLine 1010H room thermostat is recommended
for non-condensing cooling mode.
Installing a room thermostat with integrated dew point monitor
(humidity sensor) increases the reliability of cooling mode since the flow
temperature in this case is automatically controlled via the control unit
with reference to the current dew point.
▶ Installing the room thermostat with integrated Dew point humidity
sensor (instructions of the room thermostat).
▶ Electrical connection (Chapter 6.8.4).
If a room thermostat is used without an integrated dew point monitor
(humidity sensor), an additional dew point monitor (humidity sensor)
must be installed in the heating system.
▶ Fit the room thermostat in order to adjust the cooling mode of the
heating system (observe instructions for the room thermostat).
▶ Electrical connection (Chapter 6.8.4).
5.7.5 Installation with swimming pool
NOTICE
Danger of faults!
If the swimming pool mixer is installed in the wrong location in the
system, faults mayoccur. The swimming pool mixer must not be installed
in the flow where it could block the pressure relief valve.
▶ Assemble the swimming pool mixer in the return to the indoor unit (as
shown in the example image for swimming pool installation).
▶ Mount the tee in the flow from the indoor unit upstream of the bypass.
▶ Do not install the swimming pool mixer as heating circuit in the
system.
A prerequisite for using the swimming pool heating is the installation of a
swimming pool module (accessory).
▶ Installing the swimming pool (swimming pool instructions).
▶ Installing the swimming pool mixer.
▶ Insulate all pipes and connections.
▶ Install the pool module (Instructions for the pool module).
▶ Electrical connection (Chapter 6.8.6).
▶ Set the elapsed time of the swimming pool diverter valve during
commissioning (instructions for control unit).
▶ Make the necessary settings for the swimming pool mode (
instructions for control unit).
Fig. 26 Example showing swimming pool installation
[1] Swimming pool module
[2] Swimming pool
[VC1] Swimming pool mixer
[HS] Heating system
0010046700-001
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M
VC1
HS
M
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5.7.6 Connect-Key K 30 RF
Connect-Key K 30 RF is a WLAN communication module for controlling
and monitoring your heating system remotely. It is used as an interface
between the heating system and the Internet.
For further information on how to use and install the Connect-Key K 30
RF, please read the installation manual of the accessory.
A WLAN router, internet connection and the Bosch HomeCom Easy app
are required to use this product.
Installation on the wall:
Fig. 27 Placing the Connect-Key K 30 RF
When installing the holder for the Connect-Key K 30 RF on the wall:
1. Find a place next to the indoor unit that has sufficient signal quality to
communicate to the WLAN router.
2. Drill the holes to fix the bracket on the wall. For that, use a suitable
drill bit.
3. Screw on the bracket firmly to the wall.
The holder may also be placed on the side cover of the indoor unit using
the holder's incorporated magnet.
6 Electrical connection
WARNING
Risk to life from electric shock!
Touching live electrical parts can cause an electric shock.
▶ Before working on electrical parts, disconnect all phases of the
power supply (fuse/circuit breaker) and lock the isolator switch to
prevent unintentional reconnection.
WARNING
Danger to life from electric current!
Incorrectlyconnectedelectricalcables canresultin faultyoperationwith
potentially dangerous consequences.
▶ When making the electrical connections, refer to the connection
diagrams for the individual devices and components.
▶ When performing maintenance, label all power cables before
disconnecting them.
NOTICE
Material damage if the maximum current consumption is exceeded!
Short-term high (start-up) currents can can damage electrical
components.
▶ When connecting external components to the control unit, make sure
that the sum of the individual power consumption (consider the
power consumption of the boiler) does not exceed the maximum
current consumption (control unit data plate).
Note the following when making electrical connections:
▶ Electrical work on heating systems must only be carried out by
qualified electricians. If you are not suitably qualified, ask a licensed
heating contractor/electrician to establish the electrical connection.
▶ Make sure that all system components are earthed or connected to
the equipotential bonding (protective earth is a constituent part of
the control unit used).
▶ Observe all local regulations!
Connect cables as shown in the connection diagrams (Chapter 12.4,
page 40).
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6.1 Connecting the device
Due to the IP rating IPX1D, the appliance must not be installed in
protection zones 1 and 2.
Fig. 28 Protection zones
[1] Protection zone 1, directly above the bath
[2] Protection zone 2, within a radius of 60 cm from the bath/shower
6.2 Routing cables
NOTICE
Material damage due to damaged cables!
System damage may occur if cables are installed incorrectly or next to
hot system components.
▶ Make sure cables are not pinched.
▶ Route all cables through cable feeds.
Fig. 29 Cable feeds
[1] Cable feed for sensor, CAN BUS and EMS bus
[2] Cable feed for mains power supply (230 V)
NOTICE
Material damage due to induced overvoltage!
Incorrectly installed cables can lead to induced overvoltages which can
cause the control unit to malfunction or be damaged.
▶ Route 230 V cables and extra-low voltage cables separately.
EMS-BUS and CAN-BUS are not compatible.
▶ Do not connect EMS-BUS units to CAN-BUS units.
It must be possible to safely interrupt the power supply to theappliance.
▶ Install a separate safety switch that completely de-energizes the
indoor unit.
▶ For a separate power supply, a safety switch is required for each
supply line.
▶ In case a fixed appliance is not equipped with a power cable and plug
or other means to shutdowwn from the power supply that has a
contact opening width at each pole according to the conditions of
overvoltage category III for full disconnection:
Install the respective disconnecting device in the fixed electrical
installation in accordance with the installation regulations.
▶ Select the appropriate conductor cross-sections and cable types for
the respective fuse protection and routing method.
▶ Mount the enclosed terminals on the installation PCB.
▶ Connect the unit as shown in the connection diagram. No additional
consumers may be connected.
▶ When changing the PCB, note the colour coding.
Whenextendingtemperaturesensor cables,use the following conductor
diameters:
• up to 20 m long cable: 0.75 to 1.50 mm2
• up to 30 m long cable: 1.0 to 1.50 mm2
6.3 Connecting the power supply
A cable of the type H05V2V2 F, 3x1.5 mm2which is 2.5 m in length is
connected as standard to the mains power supply terminal (Fig. 30).
Alternatively an on-site connection can be established using a suitable
cable.
▶ Remove the cover (Chapter 5.3.1, page 10).
▶ Feed connecting lead through the cable feed [2] into the appliance.
▶ Establish a permanent connection to the mains power supply in
accordance with the locally applicable regulations.
▶ Connectthe mainspowersupplyvia themainspower supply terminal
on the retaining plate (Fig. 30, [2]).
WARNING
Danger to life from electrical shock in the event of incorrectly
connected cables!
Ensure correct polarity of the N and L cables.
▶ Establish clamp connection correctly.
▶ Fully tighten clamp connection.
▶ Do not use an adapter plug (push fit connections).
▶ Make sure the potentiometer setting is correct for hybrid application
(P=3 and A=0) as shown in Fig. 30, [1]. If necessary, turn the
direction arrow to the corresponding position with a screwdriver.
0 010 007 511-001
225 cm
2
21
1
60 cm
60 cm
0010029926-002
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