Viessmann Vitocal WPR 300 Operating instructions

VIESMANN
Service instructions
for contractors
Vitocal
WPR 300 heat pump control unit manual
For applicability, see the last page
VITOCAL
5366 335 GB 8/2008 Please keep safe.

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
designed for qualified personnel.
&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
Observe the following when working
on this system
&all legal instructions regarding the
prevention of accidents,
&all legal instructions regarding
environmental protection,
&theCodeofPracticeofrelevant
trade associations.
&all current safety regulations as
defined by DIN, EN, DVGW, VDE
and all locally applicable standards
Workingonthesystem
&Isolate the system from the power
supply and check that it is no longer
'live', e.g. by removing a separate
fuse or by means of a main isolator.
&Safeguard the system against
unauthorised reconnection.
!Please note
Electronic modules can be
damaged by electrostatic dis-
charges.
Touch earthed objects, such as
heating or water pipes, to dis-
charge static loads.
Repair work
!Please note
Repairing components that ful-
fil a safety function can com-
promise the safe operation of
your heating system.
Replace faulty components
only with original Viessmann
spare parts.
Safety instructions
2
Safety instructions
5366 335 GB

Ancillary components, spare and
wearing parts !Please note Spare and wearing parts that
have not been tested together
with the heating system can
compromise its function. Instal-
ling non-authorised compo-
nents and non-approved
modifications or conversions
can compromise safety and
may invalidate our warranty.
For replacements, use only ori-
ginal spare parts supplied or
approved by Viessmann.
Safety instructions (cont.)
3
Safety instructions
5366 335 GB

Introduction .............................................................................................. 9
Function description
Heat pump.................................................................................................. 11
Lag heat pumps .......................................................................................... 15
External heat source................................................................................... 16
DHW cylinders............................................................................................ 17
Instantaneous heating water heater ............................................................ 23
Heating water buffer cylinder....................................................................... 24
Heating circuit ............................................................................................ 28
Cooling mode in cooling or heating circuit ................................................... 35
Swimming pool ........................................................................................... 39
Troubleshooting
Control unit diagnostics .............................................................................. 40
Control settings - system definition
5735 No. external heat pumps !................................................................ 74
7000 System diagram !............................................................................. 74
7001 Language........................................................................................... 76
7002 Ave. time outside t §......................................................................... 76
7003 Temp. diff. heating !......................................................................... 77
7004 Temp. diff. cooling !.......................................................................... 77
7005 Red.mode t threshold §..................................................................... 78
7006 Frost protection t §............................................................................ 78
7007 Primary pump with NC §................................................................... 79
7008 Swimming pool !.............................................................................. 79
700A Cascade control !............................................................................ 80
700B Output of lag heat pumps !............................................................... 81
700D Ext.heat p f. cool §........................................................................... 81
700E Ext.heat p for DHW §........................................................................ 81
7010 External extension !......................................................................... 82
7011 Op. mode change HC !..................................................................... 82
7012 Op mode change eff. !...................................................................... 83
7013 Op. mode change time !................................................................... 83
7014 External demand / mixer OPEN !...................................................... 84
7015 External blocking/Miclose !.............................................................. 85
7016 Type Vitosolic !................................................................................ 86
7017 Vitocom 100 !.................................................................................. 87
7018 Value range 0..10 V §....................................................................... 87
7019 Priority ext. demand §....................................................................... 87
701A Ext. blocking effect !........................................................................ 88
701B Wtimer DHW Circ............................................................................... 89
Index
4
Index
5366 335 GB

Compressor control settings
Compressor control settings ....................................................................... 91
5000 Enabling !........................................................................................ 91
5001 Max. flow temp §............................................................................... 91
5002 Min. return temp. §............................................................................ 92
5004 Hysteresis primary §......................................................................... 93
5005 Min. runtime §................................................................................... 93
5006 Min. pause §..................................................................................... 94
5008 Start delay §..................................................................................... 94
500A Optimum runtime §........................................................................... 95
500B Defrost time §................................................................................... 97
500C Max. defrost start time §................................................................... 97
500D Defrost OFF time §........................................................................... 98
500E Temp. diff. defrost §.......................................................................... 98
500F Defrost start t §................................................................................. 99
5010 Defrost stop t !................................................................................. 99
5011 Max. differential t §........................................................................... 99
5012 DHW with heat pump §..................................................................... 100
5015 Max. t primary inlet §/ 5016 Min. t primary inlet §............................. 100
5019 Superheating §................................................................................. 102
501A MOP limit §...................................................................................... 102
501B EVI hot gas temp. §.......................................................................... 102
501C Compr.diff.dead zone §.................................................................... 103
501D EVI superheating §.......................................................................... 103
501E PWM cycle time §............................................................................. 104
501F Opening position §........................................................................... 104
5020 Start open duration §........................................................................ 104
5021 Max. hot gas temp. §........................................................................ 105
5022 Max. high pressure §........................................................................ 105
5023 High p dead zone §........................................................................... 106
5024 Max. superheat t §............................................................................ 106
5025 Low pressure limit §.......................................................................... 107
5026 Hysteresis low p §............................................................................ 107
5027 Low pressure delay §........................................................................ 107
5030 Output !........................................................................................... 108
5707 Number of heat pumps !................................................................... 109
External heat source control settings
7B00 Ext. heat source !............................................................................ 110
7B01 Priority !.......................................................................................... 110
7B02 Dual-mode temperature !................................................................. 110
7B03 Threshold §...................................................................................... 111
7B04 Delay §............................................................................................ 112
Index (cont.)
5
Index
5366 335 GB

7B05 Mixer t limit §.................................................................................... 112
7B06 Min. runtime §.................................................................................. 112
7B07 Runtime without demand §............................................................... 113
7B08 Mixer runtime §................................................................................ 113
7B09 Mixer active zone §/ 7B0A Mixer dead zone §................................. 114
7B0B Flow t excess §................................................................................ 114
7B0D Ext. HS for DHW !........................................................................... 115
7B0E Dual-mode operation §.................................................................... 115
DHW control settings
6000 Set DHW temp. .................................................................................. 116
6001 Switching times DHW ......................................................................... 116
6004 Operating mode §............................................................................. 117
6005 Min. temperature !........................................................................... 117
6006 Max. temp. !..................................................................................... 118
6007 Hysteresis !/ 6008 Hyst. booster heater !...................................... 119
6009 Start optimisation ............................................................................... 120
600A Stop optimisation ............................................................................... 120
600B Auxiliary function ............................................................................... 121
600C Set temp. 2 ........................................................................................ 121
600D T rise / hour §................................................................................... 122
600E Second temperature sensor !........................................................... 122
600F Excess reaction §............................................................................. 123
6010 DHW priority §.................................................................................. 123
6011 Max. runtime §.................................................................................. 124
6012 Max. DHW break §............................................................................ 124
6014 Booster heaters !............................................................................. 124
6015 DHW with e heating............................................................................ 125
Electric heater control settings
7900 Inst.htg.water heat !......................................................................... 126
7902 Electric heating .................................................................................. 126
7904 Max. flow temp §............................................................................... 127
7905 Heater rod delay §............................................................................ 127
7907 Max. stage E heating !..................................................................... 128
7908 Blocking time, power failure §........................................................... 128
7909 Stage power failure §........................................................................ 129
790A Stage at power-OFF !...................................................................... 129
Control settings - internal hydraulics
7300 HP for dry. buildings !....................................................................... 131
7303 Screed program !............................................................................. 131
7304 Hysteresis secondary §.................................................................... 133
Index (cont.)
6
Index
5366 335 GB

7305 Integral 3-way valve §....................................................................... 134
7306 Prop. 3-way valve §.......................................................................... 135
7307 Max. step 3-way v §.......................................................................... 135
7308 Heat p night op §.............................................................................. 136
7309 Heat pump run-on §.......................................................................... 136
730B Sec pump run-on §........................................................................... 136
730C Set flow ex. demand !...................................................................... 137
730D Heat/DHW diverter v §..................................................................... 137
730E E heating threshold §....................................................................... 138
Control settings - heating water buffer cylinder
7200 Buffer cylinder !............................................................................... 139
7201 Switch t buffer cyl. .............................................................................. 139
7202 Fixed temp. !.................................................................................... 140
7203 Hysteresis !..................................................................................... 140
7204 Max. temp. !..................................................................................... 141
7205 Stop optimisation §........................................................................... 141
7206 Excess reaction §............................................................................. 142
Heating circuit control settings
Heating circuit control settings .................................................................... 143
2000 Room t standard / 2001 Room t reduced ............................................. 143
2002 Switching times HC ............................................................................ 144
2003 Remote control !.............................................................................. 145
2004 Operating mode §............................................................................. 145
2005 Room control §................................................................................. 146
2006 Heating curve level / 2007 Heating curve slope................................... 147
2009 Integral room thermostat §................................................................ 148
200A Room t hook-up slope !.................................................................... 148
200B Room t hook-up !............................................................................. 148
200D Max. flow corr. §............................................................................... 149
200E Max. flow temp. !............................................................................. 149
2010 DHW for party §................................................................................ 150
2011 Excess reaction §............................................................................. 150
2012 Room t excess §............................................................................... 151
2014 Flow t excess §................................................................................. 151
2015 Mixer runtime §................................................................................. 152
2018 Mixer active zone §/ 2019 Mixer dead zone §.................................. 152
Cooling control settings
7100 Cooling !.......................................................................................... 154
7101 Cooling circuit !................................................................................ 154
7102 Room temperature ............................................................................. 155
Index (cont.)
7
Index
5366 335 GB

7103 Min. flow temp. !.............................................................................. 155
7104 Room t hook-up slope !.................................................................... 156
7105 Room control §................................................................................. 156
7106 Ranking RTS §................................................................................. 157
7107 Room t hyster.cool §......................................................................... 157
7108 Integral room thermostat §................................................................ 157
7110 Cooling curve level !/ 7111 Cooling curve slope !........................... 158
7115 NC mixer type §................................................................................ 159
Communication control settings
7710 LON module installed !..................................................................... 160
7777 Subscriber number !/ 7798 System number !................................ 160
7779 Fault manager !............................................................................... 161
7797 Outside temperature !...................................................................... 161
779C Receive heartbeat !......................................................................... 162
77FF Time !.............................................................................................. 162
Time control settings
7C00 Auto. su/w. time !............................................................................. 163
7C01 Summertime - month !..................................................................... 163
7C02 Summertime - week !....................................................................... 163
7C03 Summertime - day !......................................................................... 164
7C04 Wintertime - month !........................................................................ 165
7C05 Wintertime - week !......................................................................... 165
7C06 Wintertime - day !............................................................................ 166
Keyword index .......................................................................................... 167
Index (cont.)
8
Index
5366 335 GB

This manual explains the function, control parameters and fault messages of
the WPR 300 heat pump control unit for Viessmann heat pumps.
With the control parameters, the heat pump can be matched to varying demands
and operating conditions. To avoid incorrect operation of the heat pump or other
system components, the control parameters and fault messages are available
at three different setting levels.
Setting levels
&"System operator":
Individuals who have been trained
in the operation of the heating sys-
tem by heating engineers (contrac-
tors).
&"Contractor":
Heating engineers who have been
trained the use of Viessmann heat
pumps.
&"Expert":
Heating engineers who have com-
pleted specialist expert training for
Viessmann heat pumps.
Designation
After switching on, the setting level
"System operator" is automatically
enabled. Access to the "Contractor"
and "Expert" levels is gained by enter-
ing an access code. Control para-
meters and fault messages which are
only accessible at the "Contractor"
and "Expert" setting levels, are indi-
cated in this manual with the following
symbols:
!Available at the "Contractor" and
"Expert" setting levels. Control
parameters are displayed as plain
text.
§Only available at the "Expert" set-
ting level. No plain text display;
control parameters are identified
by numbers.
Control parameters and fault mes-
sages at the "System operator" set-
ting level have no special
identification, since they are available
without entering a code.
Note
All functions and settings are avail-
able at the "Expert" setting level. The
"Contractor" level includes the
"System operator" level.
Introduction
9
Introduction
5366 335 GB

Displays and controls
AON/OFF switch
BFault indicator (red)
CON indicator (green)
DProgramming unit
ESelection keys
F"Standard display" key
GOperating mode selector
HRotary selector "Reduced room
temperature"
KRotary selector "Standard room
temperature"
Enabling setting levels
Note
The functions of the "Contractor" and
"Expert" setting levels assume spe-
cialist knowledge in relation to
Viessmann heat pumps.
Our warranty becomes void if incor-
rect operation occurs at the "Con-
tractor" or "Expert" setting level by the
system operator or inadequately
trained personnel.
1. Call up the main menu:
Press "Standard display".
2. Enter code:
Menu item
&"Device settings"
&"Access rights"
&Enter the code using the selec-
tion keys:
5243 for "Contractor" setting
level or
3442541331 for "Expert" setting
level
&2x"OK"
Introduction (cont.)
10
Introduction
5366 335 GB

The WPR 300 heat pump control unit is suitable for the following heat pumps:
&Vitocal 300-G, type BW, BWC, WW, WWC
&Vitocal 300-A, type AWC-I, AW-O
Different parameters are available in the control unit subject to type and equip-
ment level. Parameters associated with a particular type are enabled via the
coding card. Each compressor installed and each compressor level must be
enabled individually ("Enable", 5000, 5100).
Note
The compressor parameters have the
numbers 5xxx, where 50xx describe
the parameters of compressor stage
1, and 51xx describe the same para-
meters of compressor stage 2.
Starting and stopping the compressor
If one of the following conditions is
met, the compressor starts:
&The flow temperature of the second-
ary circuit falls below (exceeds in
active cooling mode; not for the
Vitocal 300-A) the set flow tempera-
ture by more than "Hysteresis sec-
ondary" (7304).
&A heat demand is present via a
heating water buffer cylinder, DHW
cylinder or swimming pool.
In addition, the following conditions
mustbemetatthesametime:
&"Start delay" (5008) has expired.
&Min. return temperature "Min.
return temp." (5002) has been
exceeded.
&Temperature has fallen below the
max. inlet temperature of the pri-
mary circuit "Max. t primary inlet"
(5015) by "Hysteresis primary"
(5004).
&Minimum inlet temperature of the
primary circuit "Min. t primary
inlet" (5016) has been exceeded by
"Hysteresis primary" (5004).
At the beginning of the start delay, the
primary pump starts, or the fan for air/
water heat pumps. To create even,
stable thermal conditions for reliable
temperature capture, the secondary
pump also starts.
Heat pump
11
Function description
5366 335 GB

If the compressor does not start
because of a fault, the control unit
switches on other heat sources as
available. Subject to the system con-
figuration, these may be electric
instantaneous heating water heaters
or external heat sources, such as gas
or oil fired boilers. Electric immersion
heaters are available for DHW cylin-
ders and heating water buffer cylin-
ders.
If one of the following conditions is
met, the compressor stops again:
&After "Min. runtime" (5005) there is
no longer any heat demand, or the
set flow temperature has been
exceeded by "Hysteresis second-
ary" (7304).
&"Max. flow temp" (5001) or the
"Max. differential t" (5011) have
been exceeded.
&"Max. t primary inlet" (5015) has
been exceeded.
&The temperature has fallen below
"Min. t primary inlet" (5016).
&"Max. high pressure" (5022) has
been exceeded (high pressure shut-
down).
&The level has fallen below the "Low
pressure limit" (5025) (low pres-
sure shutdown).
&Power-OFF is enabled.
&The heat pump has a fault.
Frequently stopping and starting the
heat pump increases wear on the
compressor. Parameter "Min. run-
time" (5005) prevents the heat pump
shutting down within the specified
time, during which the heat produced
must be transferred to the consumers.
Whether and under what conditions
this "critical heat transfer" occurs can
be established for every consumer
individually (parameter "Excess
reaction", 2011, 600F, 7206). The
"critical heat transfer" ends when the
"Min. runtime" (5005) is reached.
However, if a heat demand is still pre-
sent, the compressor continues to
run. Heat pumps with regulated output
are set up to reach the optimum run-
time "Optimum runtime" (500A) as
frequently as possible.
After the compressor has shut down,
the control unit prevents it restarting
for the duration "Min. pause" (5006).
This also applies if the compressor
shut down because of a high pressure
fault or after the maximum flow tem-
perature "Max. flow temp" (5001)
had been exceeded.
Compressor stage 2
For reasons of modularity, compres-
sor stage 2 refers to a separate heat
pump that is not equipped with its own
control unit. Instead, it is fitted either
with its own EEV controller or thermal
expansion valve (TEV) to regulate the
refrigerant circuit. If one of the follow-
ing conditions is met, compressor
stage 2 starts:
&The heating output required is
greater than that of compressor
stage 1.
&The integral comprising the duration
and level of the set flow temperature
deviationtotheactualvalueinthe
secondary circuit exceeds the
default value "E heating thresh-
old" (730E).
Heat pump (cont.)
12
Function description
5366 335 GB

For optimised starting and stopping of
compressor stage 2, the heating out-
puts of the individual compressor
stages must be known. This is speci-
fied with parameter "Output" (5030,
5130).
Refrigerant circuit
The operating conditions in the refrig-
erant circuit are generally influenced
by the refrigerant flow rate of the elec-
tronic or thermal expansion valve
(EEV, TEV).
For an electronic expansion valve, the
valve position is regulated automati-
cally by the EEV controller, whose
control circuit works independently of
the heat pump control unit. The EEV
controller permanently communicates
with the heat pump control unit via KM
BUS.Viathis,theheatpumpcontrol
unit provides the EEV controller with
set values, and receives the current
values of the refrigerant circuit.
The EEV controller, if installed, also
regulates the vapour injection
(Enhanced Vapour Injection).
Note
Under standard operating conditions,
the refrigerant circuit is regulated to
constantly superheat the suction gas.
Under certain operating conditions, e.
g. if the max. operating pressure of
the evaporator ("MOP limit",501A)is
reached, the controller switches over
to pressurised regulation of the suc-
tion gas.
For control of the refrigerant circuit,
the following factors are taken into
account:
&Conditions and limit defaults (para-
meters 5019 to 5027)
&Refrigerant parameters (stored in a
non-volatile memory)
&Actual pressure and temperature
values
The following pressure and tempera-
ture values are captured via sensors
in the refrigerant and processed:
&Suction gas pressure
&Hot gas pressure
&Suction gas temperature
&Hot gas temperature
&Refrigerant temperature down-
stream of condenser
&Refrigerant temperature upstream
of evaporator
The heat pump control unit also uses
these values to calculate the amount
of heat transferred, necessary for the
refrigerant circuit statement. The
power consumption of the compressor
which is also required for this is calcu-
lated by the control unit from the
stored output curves. The selection
within the control unit of the curve that
matches the compressor is made via
parameter "Output" (5030, 5130).
Heat pump (cont.)
13
Function description
5366 335 GB

To assess the efficiency, the power
consumption calculated for the com-
pressor can be compared with the
total heat pump consumption for the
same period.*1The electricity meter
on site provides the total power con-
sumption. If there is a large difference
between the two output values, this
indicates that the heat pump is not
optimally matched to the other electri-
cal heat sources, e.g. instantaneous
heating water heater. In this case, the
runtimes and start criteria for these
electrical consumers must first be
checked.
If the runtimes of electrical heat
sourcesaretoolonginspiteofopti-
mum matching, the following must be
checked more closely:
&Primary and secondary flow rates
&Refrigerant circuit function
&Heat exchanger
&Extended control parameters
Seasonal performance factor (SPF)
The control unit calculates the seaso-
nal performance factor of the com-
pressor, using the ratio of transferred
heating energy to the electrical
energy consumption for the last 12
months. The current month is not
included in this statement.
For the seasonal performance factor
which is comparable to the design
valueaccordingtoVDI4650,the
power consumption of the secondary
pumps and fan (type AW) must be cal-
culated from the data of the type plate
and hours run (see statistics), and
added to the power consumption of
the compressor.
Scanning statistics
Operating instructions
Defrosting
For air/water heat pumps, the eva-
porator must be defrosted under cer-
tain outside air conditions. The heat
pump control unit starts this process
automatically. The defrost conditions
can be adjusted using the following
parameters:
&Max. time for defrosting the eva-
porator ("Defrost time",500B)
&Time delay; the defrost process
starts at the latest after this ("Max.
defrost start time", 500C)
&Blocking time for repeat defrost
("Defrost OFF time",500D)
Heat pump (cont.)
14
Function description
5366 335 GB
*1For this, also observe the runtimes (hours run) of the actuators such as pumps etc.

&Temperature differential for the start
of the defrost process ("Temp. diff.
defrost", 500E)
&Evaporator temperature for the start
of the defrost process ("Defrost
start t",500F)
&Max. evaporator temperature
("Defrost stop t", 5010).
Lag heat pumps
The heat pump control unit in the lead appliance can regulate up to four lag heat
pumps, subject to connection method. Parameter "No. of ext. heat p" (5735)
indicates the number.
Parameter "Cascade control" (700A)
determines whether the lag heat
pumps are connected to each other
via external extension H1 or via LON.
The lag heat pumps are identified for
communication via LON by allocating
them a unique number ("Number of
heat pumps", 5707). For the address
within the LON, a system and subscri-
ber number is additionally allocated.
Note
For heat pump cascades via LON, the
lead appliance must have the LON
communication module for heat pump
cascades installed.
For a heat pump cascade, the follow-
ing parameters in lead and lag heat
pumps must be set in accordance with
the following table.
Parameter Setting
Lead appliance Lag heat pump
"Cascade control", 700A 1 or 2 0
"No. of ext. heat p", 5735 1 to 3 (H1)
1to4(LON)
0
"System diagram", 7000 0 to 10 11
Heat pump (cont.)
15
Function description
5366 335 GB

Lag heat pumps are hydraulically con-
trolled in a cascade, which supplies
the heating circuits directly or via a
heating water buffer cylinder. If DHW
should be able to be heated with all
heat pumps, the three-way diverter
valve "Central/DHW heating" must be
installed at the corresponding point
downstream of the cascade. The con-
trol unit enables hook-up of the lag
heat pumps for DHW heating via para-
meter "Ext.heat p for DHW" (700E).
For this, either all or no lag heat
pumps can be used. Subject to the
hydraulic connection, either the three-
way diverter valve "central/DHW heat-
ing" or the circulation pumps for cylin-
der heating of the lag heat pumps
must be connected electrically to be
able to start and stop simultaneously
in case of heat demand.
Lag heat pumps can be enabled via
parameter "Priority ext. demand"
(7019) for swimming pool heating.
If one of the following conditions is
met, the lag heat pumps start:
&The heating output required, e.g. by
a heating water buffer cylinder, is
greater than that of the lead appli-
ance.
&The integral comprising the duration
and level of the set flow temperature
deviationtotheactualvalueinthe
secondary circuit exceeds the
default value "E heating thresh-
old" (730E).
External heat source
The heat pump control unit enables the heat pump to operate in dual-mode with
an external heat source, e.g. oil fired boiler ("Ext. heat source",7B00).
The external heat source is hydrauli-
cally connected to let the heat pump
also be used as a return temperature
raising facility for the boiler. In this
case, system separation is provided
with a low loss header or heating
water buffer cylinder.
For optimum heat pump operation, the
external heat source must be inte-
grated via a mixer in the heating water
flow. A quick reaction is achieved by
directly controlling this mixer via the
heat pump control unit.
If an instantaneous heating water
heater is installed in the secondary
circuitflow,prioritycanbesetforthe
external heat source ("Priority",
7B01).
The heat pump control unit starts the
external heat source if the following
conditions are met simultaneously:
Lag heat pumps (cont.)
16
Function description
5366 335 GB

&The outside temperature (long-term
average) is below the "Dual-mode
temp" (7B02).
&The actual value for "Threshold"
(7B03) exceeds the set value. Fol-
lowing matching of the set flow tem-
perature in the secondary circuit,
this actual value is not calculated in
the "Delay" (7B04). This occurs e.
g. after changing the operating
mode "Standard"/"Reduced" or after
switching "Central heating"/"DHW
heating".
Note
In case of direct heat demand from
the consumers, e.g. for frost protec-
tion or if the heat pump is faulty, the
external heat source is also started
above the dual-mode temperature.
Subject to the setting of parameter
"Dual-mode temp" (7B0E), solo
operation of the external heat source
is also possible.
If, after starting, the flow temperature
in the circuit of the external heat
source reaches the temperature
"Mixer t limit" (7B05), the mixer
opens and regulates the system flow
temperature to the set value. The
characteristics of the mixer can be
matched with regard to hysteresis lim-
its and runtime (parameters 7B08,
7B09, 7B0A, 7B0B). If the opening
temperature of the mixer has still not
been reached two hours after starting
the external heat source, a fault mes-
sage is displayed on the heat pump
control unit.
The heat pump control unit stops the
external heat source if the following
conditions are met:
&The "Min. runtime" (7B06) of the
external heat source is reached.
&For the duration "Runtime without
demand" (7B07), the system flow
temperature is above the set flow
temperature.
The heat pump control unit does not
contain any safety function for the
external heat source. To prevent tem-
peraturesthataretoohighintheheat
pump flow and return in case of a
fault, high limit safety cut-outs must
be provided to stop the external heat
source (switching threshold 65 °C).
DHW cylinders
Types and configuration
The DHW cylinder is enabled together with the system diagram. Diagrams with
even numbers have a DHW cylinder.
External heat source (cont.)
17
Function description
5366 335 GB

Cylinders with an internal indirect coil
("coil heat exchanger"), external heat
exchanger (cylinder primary system)
and cylinders with jacket heat exchan-
gerscanbeused.Duetothelowheat
transfer output, cylinders with jacket
heat exchangers and conventional
cylinders with an internal indirect coil
are only suitable for operation with
heat pumps.
We therefore recommend using only
cylinders with a very large heat trans-
fer surface that are built especially for
heat pumps, or a correspondingly
sized cylinder primary system. Heat
exchangers should be sized to 2 to 3
K temperature differential between
the primary and secondary side.
External heat exchangers must be
operated in countercurrent.
Note
3 K additional differential between the
heating water flow temperature and
cylinder temperature reduce the effi-
ciency of the heat pump by 10%.
A second, lower cylinder temperature
sensor can be installed in some DHW
cylinders. This sensor is enabled via
parameter "Second temperature
sensor" (600E). With this sensor, the
cylinder volume can be better utilised
in operating modes (6001) "Stan-
dard" and "Second temperature",
as well as for functions "Start optimi-
sation" (6009) and "Stop optimisa-
tion" (600A).
Heating
In the delivered condition, DHW heat-
ing has priority over the heating cir-
cuits. If required, this can be changed
with parameter "DHW priority"
(6010). As soon as a heat demand is
present from the heating circuits and
the DHW cylinder simultaneously, for
DHW priority the cylinder is only
heated for a duration of "Max. run-
time" (6011). If a heat demand is still
present at the DHW cylinder, the heat-
ing circuit is only supplied for a dura-
tion of "Max. DHW break" (6012).
For effective cylinder heating, the
DHW in the DHW cylinder should not
be mixed during this process. For this
reason, the control unit stops the
DHWcirculationpumpuntilthecylin-
der temperature reaches the second
set temperature ("Set temp. 2",
600C) up to 50% of its hysteresis
("Hysteresis", 6007).
DHW cylinders (cont.)
18
Function description
5366 335 GB

For cylinder primary systems, mixing
of the cylinder water and cooling of
the return is prevented, because the
cylinder primary pump only starts
when the flow time of the secondary
pump ("Start delay", 5008) is
reached and the heat pump produces
heating output. In the flow time, an on-
site shut-off valve in the DHW line can
additionally be closed via the cylinder
primary pump relay, and subsequently
reopened.
Operating modes
Various operating modes can be
selected for the DHW cylinder, which
are differentiated by different set tem-
peratures and different start and stop
criteria. Subject to the way the operat-
ingmodeisselected("Operating
mode", 6004), the selection is made
by the position of the operating mode
selector, the stage selected for DHW
heating ("Switching times DHW",
6001), the external operating mode
changeover or by remote control.
&"Off"
The set cylinder temperature is
"Min. temp." (6005). Heating is
started and stopped via the top
cylinder temperature sensor.
&"Top"
The set cylinder temperature is "Set
DHW temp." (6000). Heating is
started and stopped via the top
cylinder temperature sensor.
&"Standard"
The set cylinder temperature is "Set
DHW temp." (6000). Heating is
started via the top cylinder tempera-
ture sensor. To stop heating, the
control unit uses the bottom sensor
(if installed), or otherwise also the
top one.
&"Second temperature"
The set cylinder temperature is "Set
temp. 2" (600C). Heating is started
via the top cylinder temperature
sensor. To stop heating, the control
unit uses the bottom sensor (if
installed), or otherwise also the top
one.
The cylinder demands heating in all
operating modes when the current
temperature at the start sensor falls
below the set value by more than
"Hysteresis" (6007). If the tempera-
ture at the stop sensor rises above the
set value, or as soon as "Max. temp"
(6006) is reached, cylinder heating is
stopped.
DHW cylinders (cont.)
19
Function description
5366 335 GB

Booster heaters
Booster heaters, e.g. an immersion
heater, external heat source or instan-
taneous heating water heater can be
used for DHW heating. The control
unit enables the individual appliances
for DHW heating with the following
parameters:
&Immersion heater:
Parameters "Booster heater"
(6014) and "DHW with e heating"
(6015) must be set to "Yes".
&External heat source:
Parameters "Booster heater"
(6014) and "Ext. HS for DHW"
(7B0D) must be set to "Yes".
&Instantaneous heating water heater:
Parameters "Inst.htg.water heat"
(7900) and "DHW with e heating"
(6015) must be set to "Yes".
The integral load manager in the heat
pump control unit decides which heat
sources to use for DHW heating. Gen-
erally the external heat source has
priority over the electric heaters.
If one of the following criteria is met,
the booster heaters begin cylinder
heating:
&Cylinder temperature is below 3 °C
(frost protection).
&Heat pump does not provide any
heating output and temperature has
fallen below set temperature at the
top cylinder temperature sensor by
more than "Hyst. booster heater"
(6008).
&Expected temperature rise ("T rise /
hour", 600D) is not reached by
heating with the heat pump.
The expected temperature rise is
calculated as follows:
ΔTbst =theat∙SSTS +ϑKW
ΔTbst Expected temperature rise
through booster heater
theat Current cylinder heating run-
time
SSTS Temperature rise per hour "T
rise / hour" (600D)
ϑKW Cold water temperature (stan-
dardvalue20°C)
Please note that some booster hea-
ters are only regulated by the top tem-
perature sensor. The immersion
heater in the DHW cylinder and the
external heat exchanger stop as soon
as the set value at the top tempera-
ture sensor is reached, minus a hys-
teresis of -1 K.
DHW cylinders (cont.)
20
Function description
5366 335 GB