Viessmann Vitocal 350-A AWHO 351.A Series Quick guide

Installation and service instructions
for contractors
VIESMANN
Vitocal 350-A
Type AWHI 351.A
Type AWHO 351.A
Air/water heat pump with electric drive, 400 V~
VITOCAL 350-A
5692878 GB 11/2017 Please keep safe.

2
Please follow these safety instructions closely to
prevent accidents and material losses.
Safety instructions explained
Danger
This symbol warns against the risk of injury.
!Please note
This symbol warns against the risk of material
losses and environmental pollution.
Note
Details identified by the word "Note" contain additional
information.
Target group
These instructions are exclusively intended for author-
ised contractors.
■Work on the refrigerant circuit may only be carried
out by authorised refrigeration engineers.
■Work on electrical equipment must only be carried
out by a qualified electrician.
■The system must be commissioned by the system
installer or a qualified person authorised by the
installer.
Regulations to be observed
■National installation regulations
■Statutory regulations for the prevention of accidents
■Statutory regulations for the protection of the envi-
ronment
■Codes of Practice of the relevant trade associations
■All relevant safety regulations as defined by DIN, EN,
DVGW, VDE and locally applicable standards
aÖNORM, EN and ÖVE
cSEV, SUVA, SVTI, SWKI and SVGW
Safety instructions for working on the system
Working on the system
■Isolate the system from the power supply, e.g. by
removing the separate fuse or by means of a mains
isolator, and check that it is no longer live.
Note
In addition to the control circuit there may be several
power circuits.
Danger
Contact with live components can result in
severe injuries. Some components on PCBs
remain live even after the power supply has
been switched off.
Prior to removing covers from the appliances,
wait at least 4 minutes until the voltage has
completely dropped out.
■Safeguard the system against reconnection.
■Wear suitable personal protective equipment when
carrying out any work.
Danger
Hot surfaces can cause burns.
■Before maintenance and service work, switch
OFF the appliance and let it cool down.
■Never touch hot surfaces on the appliance, fit-
tings or pipework.
!Please note
Electronic assemblies can be damaged by elec-
trostatic discharge.
Prior to commencing work, touch earthed
objects such as heating or water pipes to dis-
charge static loads.
Repair work
!Please note
Repairing components that fulfil a safety func-
tion can compromise the safe operation of the
system.
Replace faulty components only with genuine
Viessmann spare parts.
Safety instructions
Safety instructions
5692878

3
Auxiliary components, spare and wearing parts
!Please note
Spare and wearing parts that have not been tes-
ted together with the system can compromise its
function. Installing non-authorised components
and making non-approved modifications or con-
versions can compromise safety and may inva-
lidate our warranty.
For replacements, use only original spare parts
supplied or approved by Viessmann.
Safety instructions
Safety instructions (cont.)
5692878

4
1. Information Disposal of packaging ............................................................................ 6
Symbols ................................................................................................. 6
Intended use .......................................................................................... 6
Product information ................................................................................ 7
2. Preparing for installation General information on the electrical connection ................................... 8
Internal heat pump ................................................................................. 8
■Installation room requirements ........................................................... 8
■Positioning .......................................................................................... 9
■Connections ........................................................................................ 12
External heat pump ................................................................................ 13
■Installation requirements .................................................................... 13
■Positioning .......................................................................................... 14
■Connections ........................................................................................ 17
3. Installation sequence Removing the transport brackets ........................................................... 21
Type AWHI 351.A only: Fitting the supplied floor mat ........................... 22
Fitting the outer panels .......................................................................... 23
Type AWHO 351.A only: Fitting the silencer hoods ............................... 28
Fitting the top panel ............................................................................... 29
Siting the heat pump .............................................................................. 29
■Connecting the air circuit (primary circuit) (only for type AWHI 351.A) 29
■Levelling the heat pump ..................................................................... 29
Hydraulic connections ............................................................................ 31
■Type AWHI 351.A ............................................................................... 32
■Type AWHO 351.A ............................................................................. 33
Control panel electrical connections ...................................................... 34
■Opening the control panel .................................................................. 34
■Overview of electrical connections in the control panel ...................... 35
■Routing cables/leads to the control panel ........................................... 36
■Attaching the connecting cables from the control unit in the control
panel ................................................................................................... 38
Heat pump control unit electrical connections ....................................... 39
■Fitting the heat pump control unit and inserting cables ...................... 39
■Attaching cables from the control panel in the control unit ................. 43
■Adapting the heat pump control unit ................................................... 43
■Inserting the coding card .................................................................... 45
■Overview of electrical connections ..................................................... 46
■Main PCB (operational components 230 V~) ..................................... 47
■Expansion PCB on main PCB (operational components 230 V~) ...... 49
■Cross connect PCB ............................................................................ 52
■Controller and sensor PCB (sensors) ................................................. 54
Power supply ......................................................................................... 58
■Heat pump control unit power supply 230 V~ ..................................... 59
■Compressor power supply (400 V~), sealing economy tariff connec-
tion for compressor ............................................................................. 59
■Power supply with power-OFF ........................................................... 60
■Phase monitor (if installed) ................................................................. 62
Closing the heat pump ........................................................................... 64
■Closing the control panel .................................................................... 65
■Fitting the front panel .......................................................................... 66
4. Commissioning, inspec-
tion, maintenance
Steps - commissioning, inspection and maintenance ............................ 67
5. Troubleshooting Repairs .................................................................................................. 80
■Overview of sensors, drain and air vent valves .................................. 80
■Draining the heat pump on the secondary side .................................. 80
■Checking the sensors ......................................................................... 80
■Check fuses ........................................................................................ 81
Index
Index
5692878

5
6. Parts list type AWHI 351.A Overview of assemblies ......................................................................... 83
Casing .................................................................................................... 84
■Front panels ........................................................................................ 84
■Side panels ......................................................................................... 86
■Miscellaneous ..................................................................................... 88
Air module .............................................................................................. 90
Heat pump control unit ........................................................................... 92
Electrical equipment .............................................................................. 94
■Type AWHI 351.A10 and AWHI 351.A14 ............................................ 94
■Type AWHI 351.A20 ........................................................................... 96
Heat pump module ................................................................................ 98
Base frame ............................................................................................ 102
7. Parts list type AWHO 351.A Overview of assemblies .........................................................................105
Casing ....................................................................................................106
■Front panels ........................................................................................106
■Side panels .........................................................................................108
■Silencer hood ...................................................................................... 110
■Miscellaneous ..................................................................................... 112
Air module ..............................................................................................114
Heat pump control unit ...........................................................................116
Electrical equipment .............................................................................. 118
■Type AWHO 351.A10 and AWHO 351.A14 ........................................ 118
■Type AWHO 351.A20 ......................................................................... 120
Heat pump module ................................................................................ 122
Base frame ............................................................................................ 126
8. Commissioning/service
reports
Hydraulic parameter report .................................................................... 128
Control parameter report ....................................................................... 128
9. Specification Specification .......................................................................................... 132
Sound transmission data ....................................................................... 135
10. Appendix Heat pump commissioning order ........................................................... 136
11. Certificates Declaration of conformity ....................................................................... 137
12. Keyword index ................................................................................................................138
Index
Index (cont.)
5692878

6
Please dispose of packaging waste in line with statu-
tory regulations.
DE: Use the disposal system organised by
Viessmann.
AT: Use the ARA statutory disposal system (Altstoff
Recycling Austria AG, licence number 5766).
CH: Packaging waste is disposed of by the HVAC
contractor.
Symbols
Symbol Meaning
Reference to other document containing
further information
1.
Step in a diagram:
The numbers correspond to the order in
which the steps are carried out.
Warning of material losses and environ-
mental pollution
Live electrical area
Pay particular attention.
■Component must audibly click into place.
or
■Acoustic signal
■Fit new component.
or
■In conjunction with a tool: Clean the sur-
face.
Dispose of component correctly.
Dispose of component at a suitable collec-
tion point. Do not dispose of component in
domestic waste.
The steps in connection with commissioning, inspec-
tion and maintenance are found in the "Commission-
ing, inspection and maintenance" section and identified
as follows:
Symbol Meaning
Steps required during commissioning
Not required during commissioning
Steps required during inspection
Not required during inspection
Steps required during maintenance
Not required during maintenance
Intended use
The appliance is only intended to be installed and
operated in sealed unvented heating systems that
comply with EN 12828, with due attention paid to the
associated installation, service and operating instruc-
tions.
Depending on the version, the appliance can only be
used for the following purposes:
■Central heating
■Central cooling
■DHW heating
Information
Disposal of packaging
5692878
Information

7
The range of functions can be extended with additional
components and accessories.
Intended use presupposes that a fixed installation in
conjunction with permissible, system-specific compo-
nents has been carried out.
Commercial or industrial usage for a purpose other
than central heating/cooling or DHW heating shall be
deemed inappropriate.
Incorrect usage or operation of the appliance (e.g. the
appliance being opened by the system user) is prohibi-
ted and will result in an exclusion of liability. Incorrect
usage also occurs if the components in the heating
system are modified from their intended function.
Note
The appliance is intended exclusively for domestic or
semi-domestic use, i.e. even users who have not had
any instruction are able to operate the appliance
safely.
Product information
Layout
The Vitocal 350-A is an air source heat pump with out-
put-dependent control.
Type AWHI 351.A is installed inside the building. Air
drawn in is supplied to the heat pump via an air duct.
Expelled air similarly leaves the building via an air
duct.
Type AWHO 351.A is installed outside the building.
The hydraulic connection lines are routed below
ground and must be frost-proof.
Hydraulics
To supply the secondary circuit, either two circulation
pumps (secondary pump and circulation pump for cyl-
inder heating) or 1 secondary pump and a 3-way
diverter valve are connected.
On type AWHI, the secondary pump can be built into
the heat pump. The remaining components are instal-
led outside the appliance.
On type AWHO, the hydraulic components for supply-
ing the secondary circuit are installed outside the heat
pump.
Central heating
The heat pump is able to supply up to 3 heating cir-
cuits: 1 heating circuit without mixer and 2 heating cir-
cuits with mixer. The mixer extension kit (accessories)
is required to control the mixer for the second heating
circuit with mixer.
Central cooling
Central cooling results either through a heating/cooling
circuit or via a separate cooling circuit. For this, the
refrigerant circuit is reversed and heat is extracted
from the cooling circuit.
Heat pump control unit
The entire heating system is monitored and controlled
by the integral Vitotronic 200, type WO1B heat pump
control unit.
System examples
For available system examples, see www.viessmann-
schemes.com
Information
Intended use (cont.)
5692878
Information

8
■Connecting control panel cables – heat pump
control unit:
Observe information from page 34.
■Electrical connection of system components
(pumps, mixers, valves, message facilities, contac-
tors, function extensions, sensors etc.):
Connections are made in the heat pump control unit.
Observe information from page 39.
■Power supply:
The number of power cables from the distribution
board (meter box) to the heat pump control unit and
the control panel depends on the system version and
tariffs used.
Connections are made in the heat pump control
panel. Observe information from page 58.
Internal heat pump
Installation room requirements
!Please note
Incorrect ambient conditions can result in sys-
tem damage and can put safe operation at risk.
■The installation room must be dry and free
from the risk of frost.
Ensure ambient temperatures are above 0 °C
and below 35 °C.
■Prevent air contamination by halogenated
hydrocarbons (e.g. as contained in paints, sol-
vents or cleaning fluids) and excessive dust
(e.g. through grinding/polishing work).
■Prevent consistently high humidity levels (e.g.
caused by continuous drying of washing).
!Please note
Overloading the floor can result in building dam-
age.
Observe the permissible floor load.
■Total weight:
AWHI 351.A10 287 kg
AWHI 351.A14 297 kg
AWHI 351.A20 361 kg
■To prevent the transmission of structure-borne noise,
never site the appliance on ceilings with wooden
joists (e.g. in the attic).
■Observe required minimum clearances.
■Level the appliance horizontally.
■Min. required room height 2.10 m
■Observe the necessary minimum room volume to
EN 378:
AWHI 351.A10 13.55 m3
AWHI 351.A14 16.13 m3
AWHI 351.A20 17.10 m3
Note
During defrosting, cool vapour escapes from the air
duct on the discharge side. This must be taken into
consideration during installation (choosing the installa-
tion room, determining the intake and discharge side).
Preparing for installation
General information on the electrical connection
5692878
Installation

9
Positioning
Minimum clearances and dimensions when posi-
tioning in a corner
Note
Before making the wall openings, check the structural
analysis of the building and the wall. If necessary, fit a
support.
For corner installation (l.h. or r.h. discharge), the wall
outlets are the same size.
BA
1330
532
1330
935
c
830
990
g
D
C
Fig. 1
AWall duct, discharge side
BWall duct, intake side
CPlaster finish
DTop edge, finished floor
Preparing for installation
Internal heat pump (cont.)
5692878
Installation

10
Discharge side on the left Discharge side on the right
K
M
G
B
AD E F
H
N
D
F
E
80
810
a
b
c
532 127
117
810
686
80
d
700
h
500
K
M
GBA
D
E
F
H
N
D
F
E
80
810 a
b
c
532
127
117
810
686
80
e
700
h
600
AExterior rendering
BWall
DWall duct (EPP, can be trimmed to the correct size
from the outside with a saw. Observe plaster thick-
ness)
ECompression sealing tape and acrylic airtight
seam (all-round)
FPU foam (all-round)
GAppliance connector, air duct, intake side (EPP)
HPlaster finish/wall coating
KHydraulic and condensate connections
MHeat pump
NAppliance connector, air duct on the discharge
side (EPP)
Dimension Vitocal 350-A, type AWHI
351.A10 351.A14 351.A20
a mm 95 85 107
b mm 118 182 284
c mm 522 588 689
d mm 367 217 64
e mm 489 489 472
g mm 880 1020 1180
h mm 845 995 1148
Note
Observe the minimum room height of 2100 mm.
Minimum clearances and dimensions for wall
installation
990
gX830
Q
1330
Fig. 2 Dimension g: See page 10.
QPartition wall (if required): See the following table.
X Distance between wall openings inside the building
Preparing for installation
Internal heat pump (cont.)
5692878
Installation

11
E
127.5
885N x 350
810
830
Y
X
g
830
240
80
A B E F G
H
KM
N P
e
Q
D
F
DD
Fig. 3 Dimensions e and g: See page 10.
AExterior rendering
BWall
DWall duct (EPP, can be trimmed to the correct size
from the outside with a saw. Observe plaster thick-
ness)
ECompression sealing tape and acrylic airtight
seam (all-round)
FPU foam (all-round)
GAppliance connector, air duct, intake side (EPP)
HPlaster finish/wall coating
KHydraulic and condensate connections
MHeat pump
NAppliance connector, air duct on the discharge
side (EPP)
PAir duct 90° bend
QPartition wall (if required): See the following table.
N Number of duct parts (wall ducts)
X Distance between wall openings inside the building
Y Distance between wall openings outside the build-
ing
Distances between wall openings X and Y in mm
N Vitocal 350-A, type AWHI Partition wall N
required
351.A10 351.A14 351.A20
X Y X Y X Y
1 655 680 660 755 665 840 Yes
2 1005 1030 1010 1105 1015 1190 Yes
3 1355 1380 1360 1455 1365 1540 Yes
4 1705 1730 1710 1805 1715 1890 Yes
5 2055 2080 2060 2155 2065 2240 Yes
6 2405 2430 2410 2505 2415 2590 Yes
7 2755 2780 2760 2855 2765 2940 Yes
8 3105 3130 3110 3205 3115 3290 No
9 3455 3480 3460 3555 3465 3640 No
10 3805 3830 3810 3905 3815 3990 No
Preparing for installation
Internal heat pump (cont.)
5692878
Installation

12
Connections
D
B
C
A
B
D
A
C
b
95
d
a
946
1870
655
790
115
220
330
440
946
c
Fig. 4 Dimensions excluding casing panels:
790 mm x c
ACable entries
BHeating water return/DHW cylinder return G 1½
(female thread)
CCondensate drain
DHeating water flow/DHW cylinder flow G 1½
(female thread)
Notes
■Air discharge, optionally l.h. or r.h. side
■Hydraulic lines and condensate drain can be routed
from the heat pump from the left or right. They are
always installed opposite the air discharge.
■The connecting hoses can be shortened. The stated
dimensions a and b are for hose lengths in delivered
condition.
Dimensions in mm
Type a b c d
AWHI
351.A10
489 367 880 891
AWHI
351.A14
489 217 1030 1041
AWHI
351.A20
472 64 1200 1211
Preparing for installation
Internal heat pump (cont.)
5692878
Installation

13
Cables/leads
E
L
A
F
K
D
CB
M
H
G
Q
P
N
R
Fig. 5
AHeat pump
BLV lead, pre-manufactured
CControl cable, pre-manufactured
DFlexible power cable (special tariff/load current):
According to compressor output, cable length and
routing, e.g. 5 x 2.5 mm2.
EOutside temperature sensor, sensor lead:
2 x 0.75 mm2
FControl unit, flexible power cable: 5 x 1.5 mm2 with
power-OFF contact power cable, floating
GElectricity meter/mains
HDHW cylinder
KCylinder temperature sensor, sensor lead:
2 x 0.75 mm2
LDHW circulation pump, power cable: 3 x 1.5 mm2
MFlexible power cable for instantaneous heating
water heater (accessories):
400 V: 5 x 2.5 mm2
230 V: 7 x 2.5 mm2
NHeating water buffer cylinder
PSecondary pump, power cable: 3 x 1.5 mm2
QHeating circuit pump
RBuffer temperature sensor, sensor lead:
2 x 0.75 mm2
Required cable/lead lengths:
■For the heat pump control unit (wall outlet centrally
directly below the heat pump control unit):
0.6 m from wall outlet
■Inside the heat pump (to the control panel):
3.4 m plus wall clearance
External heat pump
Installation requirements
■Provide a manual drain for the heating water flow
and return lines in any area at risk from frost.
If the heat pump control unit and heating circuit
pump are ready for operation, the frost protection
function of the heat pump control unit is enabled.
Drain the system if the heat pump is shut down or
there is a prolonged power failure.
On heat pump systems where a power failure cannot
be recognised (holiday home), operate the heating
circuit with a suitable antifreeze or drain it.
■To prevent "air short circuits" and an increase in
noise level due to reflection, avoid siting equipment
in recesses, at building corners or between 2 walls.
Lawn areas and vegetation can reduce noise gener-
ation.
Therefore, only the heat pump foundations should
be made from reverberant material (concrete).
■Never install the heat pump next to living rooms or
bedrooms.
■The air in the discharge area is approx. 10 K colder
than the ambient air. Therefore, black ice could
develop in the discharge area even at [ambient] tem-
peratures above freezing. A clearance of ≥ 3 m must
be observed to pavements or patios.
Note
During defrosting, cool vapour escapes from the heat
pump air discharge vents. This vapour build-up must
be taken into consideration during installation (choos-
ing the installation location, orientation of the heat
pump).
Preparing for installation
Internal heat pump (cont.)
5692878
Installation

14
Positioning
Minimum clearances
1500
1200
1200
1500
Fig. 6
Foundations
Site the heat pump horizontally on a permanently solid
surface. We recommend laying concrete foundations
as shown in the following diagrams.
■Provide an adequately sized recess (see diagram
below) in the foundations to permit the lines (heating
water flow and return, cables and condensate drain)
to be brought into the heat pump from below.
■Design the foundations, supporting surface and
cable ducts so that small animals cannot get into the
heat pump or cable ducts.
■Drain all condensate derived from the air (subject to
temperature and relative humidity up to 20 l/h) via a
DN 40 drain pipe, which should be protected from
frost and provide a steady fall.
If possible connect the condensate drain to a drain-
age or sewer system. In this case, provide a siphon
with a backup level of at least 60 mm in the frost-pro-
tected area.
Where the ground is able to absorb water, the con-
densate can be soaked away down to a frost-free
depth into a gravel bed.
■Where appropriate, provide thermal insulation or a
ribbon heater around the condensate drain hose on
site.
Technical guide
Vitocal 350-A, type Weight (with silenc-
er hoods)
AWHO 351.A10 325 kg
AWHO 351.A14 335 kg
AWHO 351.A20 400 kg
Preparing for installation
External heat pump (cont.)
5692878
Installation

15
Foundation dimensions: Plan view
100 400
100
400
100
1300
100
1150
300
250
390
320
a
H H
LP AB
b
315
340
75
145
240
V E D
G
W
M
Fig. 7
AHeat pump
BConcrete foundation (300 mm thick) consisting of:
■Concrete slab C25/30, BSt 500 S and M
■Reinforcement with all-round Q 257 A wire mesh
DKG conduit DN 100 for connecting cables to the
heat pump control unit (on site):
Control cable 230 V~, LV lead < 42 V
EHydraulic connection set (accessories): Hydraulic
connection lines for heating water flow and heating
water return
GCondensate drain DN 40 (on site)
HSoft ground, gravel or crushed stone
LUpstream direction of pipe from hydraulic connec-
tion set
MHeat pump power cable
PUnderground channel
VRecess in the foundations for routing the lines for
heating water flow and return, the condensate
drain and the connecting cables (low voltage and
control cables) as well as the power cable to the
control panel
WDownstream direction of pipe from hydraulic con-
nection set
Preparing for installation
External heat pump (cont.)
5692878
Installation

16
Dimension Vitocal 350-A, type AWHO
351.A10 351.A14 351.A20
a mm 1080 1230 1400
b mm 195 195 195
Connection dimensions for hydraulic connection
set on foundations: Cross-section
K
H
B
E
M
400
500
900
300
400
H
G
D
F
A
E
B
37
8
K
Fig. 8
AHeat pump
BConcrete foundation (300 mm thick) consisting of:
■Concrete slab C25/30, BSt 500 S and M
■Reinforcement with all-round Q 257 A wire mesh
DKG conduit DN 100 for connecting cables to the
heat pump control unit (on site):
Control cable 230 V~, LV lead < 42 V
EHydraulic connection set (accessories): Hydraulic
connection lines for heating water flow and heating
water return
GCondensate drain DN 40 (on site)
HSoft ground, gravel or crushed stone
KFrost protection (compacted crushed stone,
e.g. 0 to 32/56 mm); thickness of layer subject to
local requirements and building regulations
MHeat pump power cable
Note
■Before laying the concrete foundations, trim the
hydraulic connection pipes (heating water flow and
return), install the connection fittings and provide
frost protection.
■The power cable may be routed freely up through the
foundation opening. What is important is spatial sep-
aration between LV lead and control cable.
Preparing for installation
External heat pump (cont.)
5692878
Installation

17
Connections
i
1265
g
f
h
957
1885
e
946
A
B
C
D
D
Fig. 9
ACondensate drain
BHeating water flow G 1¼ (female thread):
Adaptor G 1¼ to Rp 1 supplied
CHeating water return G 1¼ (female thread):
Adaptor G 1¼ to Rp 1 supplied
DSilencer hoods
Dimensions in mm
Type e f g h i
AWHO
351.A10
655 456 500 1380 891
AWHO
351.A14
655 606 650 1530 1041
AWHO
351.A20
655 754 798 1700 1211
Preparing for installation
External heat pump (cont.)
5692878
Installation

18
Cables/leads and hydraulic lines
Laying the lines underground and routing in through the exterior wall
M
N
M
Q P
F
RO
O
M
N
400
N
K
O
N
P
T
S
U
B
20
900
Fig. 10
BConcrete foundation (300 mm thick) consisting of:
■Concrete slab C25/30, BSt 500 S and M
■Reinforcement with all-round Q 257 A wire mesh
CKG conduit DN 100 for power cable (on site)
DKG conduit DN 100 for connecting cables to the
heat pump control unit (on site):
Control cable 230 V~, LV lead < 42 V
EHydraulic connection set (accessories): Connec-
tion lines for heating water flow and heating water
return
FCondensate drain DN 40 (on site)
KFrost protection (compacted crushed stone,
e.g. 0 to 32/56 mm); thickness of layer subject to
local requirements and building regulations
MFlexible power cable to compressor/fan (on site)
N2 connecting cables inside DN 100 KG conduit (on
site), fully wired (5, 15 or 30 m):
■Control cable 230 V~
■LV lead < 42 V
Note
The maximum lead length is 30 m. Extensions
are not permissible.
OHydraulic connection lines (heating water flow and
heating water return)
PUnderground channel
QWall duct with expanding mortar (on site) for
hydraulic connection line
RMoisture-proof and waterproof wall ducts (on site)
SDrain & fill facility with shut-off valve (for draining
with compressed air)
TExpansion vessel with safety assembly (accesso-
ries)
UClearance, house wall — foundations:
■Max. clearance depends on length of connecting
cables and hydraulic connection lines:
Max. 23 m
■Maintain the minimum clearance to other objects
(> 1.5 m) when siting.
Heating water connection (hydraulic connection
lines O)
Use the hydraulic connection set (accessory). The
connection set is fully prepared in different lengths.
The flow and return lines are flexible and have 2 adap-
tors each. The lines are located inside a common ther-
mal insulation.
Preparing for installation
External heat pump (cont.)
5692878
Installation

19
Vitocal 350-A, type AWHO 351.A20
■Flow/return lines: 2 x DN 40
■Adaptors: DN 40 to R 1¼
■Lines are fed into building Q through a wall duct
with expanding mortar (on site).
■Provide a drain & fill facility S for heating water flow
and return in the building near an external wall and
0.8 m below ground level.
Note
In buildings at ground level, provide a thermally insu-
lated duct or enable draining of the heat pump with
compressed air.
Frost protection
If the heat pump control unit and heating circuit pump
are ready for operation, the frost protection function of
the heat pump control unit is enabled. Drain the sys-
tem via the drain & fill facility S when the heat pump
is taken out of use or if the power fails for a long
period.
In heat pump systems where a power failure would not
be detected (holiday home), the heating circuits can be
operated with suitable antifreeze. To ensure trouble-
free heat pump operation, use antifreeze based on gly-
col. Ready-mixed solutions ensure an even distribution
of concentrate.
Recommendation: Use Viessmann "Tyfocor" heat
transfer medium which is based on ethylene glycol
(ready-mixed down to −19 °C, light green).
Power cable M
Observe the technical connection requirements
imposed by your local power supply utility.
■Run the power cable to control panel M outside the
building as an SWA cable (NYY) or route an NYM
cable inside a KG conduit.
■Cable length required in the heat pump from top
edge of foundation: Min. 2.6 m.
Connecting cables N
Route prepared connecting cables (control cable
230 V~, LV lead < 42 V) N outside the building in a
KG conduit DN 100. Protect the plugs at the ends of
the cables from dirt and damage (e.g. with bubble
wrap).
Cable length required in the heat pump from top edge
of foundation
■Control cable 230 V~: Min. 0.9 m
■LV lead < 42 V: Min. 0.7 m
Routing KG conduits C, D
■Provide a wire pull for the cables (M, N).
■To facilitate the routing of cables D through the KG
conduit, avoid 90° bends; instead use 3 x 30° or 2 x
45°.
■Route the KG conduit with a slope towards the heat
pump and fit a condensate drain if required.
■Ensure that wall ducts R are moisture-proof and
waterproof.
■Seal the apertures of the KG conduit so that no ani-
mals or moisture can enter the building.
Preparing for installation
External heat pump (cont.)
5692878
Installation

20
Wiring diagram
S
R
AE
F
K
L
NM
P
BC
D
O
H
G
T
Fig. 11 Standard system example
AHeat pump
BLV lead, pre-manufactured
CControl cable, pre-manufactured
DFlexible power cable for special tariff/load current:
According to compressor output, cable length and
routing, e.g. 5 x 2.5 mm2
EOutside temperature sensor, sensor lead
(2 x 0.75 mm2)
FControl unit, flexible power cable (5 x 1.5 mm2)
with power-OFF contact power cable, floating
GElectricity meter/mains
HDHW cylinder
KCylinder temperature sensor, sensor lead
(2 x 0.75 mm2)
LCirculation pump for cylinder heating or 3-way
diverter valve, power cable (3 x 1.5 mm2)
MDHW circulation pump, power cable (3 x 1.5 mm2)
NHeating circuit pump, power cable (3 x 1.5 mm2)
OPower cable for instantaneous heating water
heater switching module
400 V: 5 x 2.5 mm2
230 V: 7 x 2.5 mm2
PInstantaneous heating water heater (accessories)
RSecondary pump, power cable (3 x 1.5 mm2)
SHeating water buffer cylinder
TCylinder temperature sensor, sensor lead
(2 x 0.75 mm2)
Required cable/lead lengths:
■For the heat pump control unit (wall outlet centrally
directly below the heat pump control unit):
0.6 m from the wall outlet
■Inside the heat pump (to the control panel):
2.6 m from the top edge of the foundations
Note
If additional heating circuits with mixer, external heat
generators (gas/oil/wood), remote control, etc. are
being installed, the additionally required supply and
control cables and sensor leads must be factored in.
Preparing for installation
External heat pump (cont.)
5692878
Installation