Danfoss DHP-H User manual

USER’S MANUAL
DHP-H, DHP-L, DHP-C, DHP-A
Navigate the control computer’s menus using:
To increase or reduce the set values use:
To adjust the room temperature: start by pressing
The degree information that now appears in the display is the
last desired room temperature.
To increase the temperature: press
To lower the temperature: press
The temperature you now require is registered immediately.
(After approximately ten seconds the desired room tempera-
ture appears in the display again, together with other infor-
mation.) The heat pump now starts to work to reach the new
temperature.
VUBMA102

VUBMA102

Danfoss – 3VUBMA102
Table of contents
1 Importantinformation........................................................4
1.1 Safetyprecautions..................................................................... 4
1.2 Protection............................................................................. 5
2 Aboutyourheatpump........................................................6
2.1 Principlesoffunction .................................................................. 6
2.2 Components........................................................................... 7
2.3 Auxiliary heat, DHP-H,DHP-L,DHP-C ...................................................... 8
2.4 Auxiliary heat, DHP-A..................................................................... 8
2.5 Water heater, DHP-H,DHP-C............................................................... 8
2.6 Water heater, DHP-A ...................................................................... 9
2.7 Regulationinformation ................................................................ 9
2.8 Installation principle, DHP-H,DHP-C......................................................15
2.9 Installation principle, DHP-L..............................................................16
3 Controlcomputer ...........................................................18
3.1 Display............................................................................... 19
3.2 Menus ............................................................................... 22
4 Trimmingtheheatingsystem ................................................29
5 Instructions ................................................................30
5.1 Settingoperatingmode............................................................... 30
5.2 SettingROOMvalues ................................................................. 30
5.3 AdjustingCURVEvalues............................................................... 30
5.4 Adjusting a specific part of the heat curve. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.5 SettingMINandMAXvalues .......................................................... 31
5.6 SettingHEATSTOP.................................................................... 31
5.7 Readingofftemperatures............................................................. 32
5.8 Calculating energy consumption, DHP-H,DHP-L,DHP-C...................................33
5.9 Calculating energy consumption, DHP-A .................................................34
5.10 Manual defrost, DHP-A...................................................................34
6 Regularchecks..............................................................35
6.1 Checkingoperation................................................................... 35
6.2 Checkingthebrinelevel .............................................................. 36
6.3 Checking the water level in the heating system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
6.4 Checkingthesafetyvalve............................................................. 37
6.5 Intheeventofleakage................................................................ 37
6.6 Cleaning the strainer for the heating system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
6.7 Cleaning the strainer for the brine circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
7 Accessories .................................................................39
7.1 Roomtemperaturesensor............................................................. 39
8 Troubleshooting ............................................................40
8.1 Alarm................................................................................ 40
9 Termsandabbreviations.....................................................42
10 Default settings in the control computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
10 References..................................................................45

Danfoss – 4 VUBMA102
1 Important information
• If the installation is not used during the winter, the heating system must be drained of
water, otherwise there is a risk of frost damage to the installation. (Contact an authorized
installer, see the ”References” section.)
• The installation can be considered maintenance free but certain checks are necessary (see
“Regular checks” section).
• Before changing the control computer’s settings, first find out what these changes mean.
• Contact your installer for any service work.
1.1 Safety precautions
1.1.1 Installation and maintenance
• Only authorized installers may install, operate and carry out maintenance and repair work
on the heat pump. (See the ”References” section)
• Only authorized electricians may modify the electrical installation. (See the ”References”
section)
DANGER TO LIFE! Only authorized refrigeration technicians may work on the refriger-
ant circuit. (See the ”References” section).
1.1.2 System modifications
Only authorized installers may carry out modifications on the following components:
• The heat pump unit
• The pipes for the refrigerant, brine, water and power
• The safety valve
You must not carry out construction installations that may affect the operational safety of the
heat pump.
1.1.3 Safety valve
The following safety precautions apply to the hot water circuit’s safety valve with correspond-
ing overflow pipe:
• Never block the connection to the safety valve’s overflow pipe.
• Water expands when it is heated, this means that a small amount of water is released
from the system via the overflow pipe. The water that exits the overflow pipe can be hot!
Therefore, allow it to flow to a floor drain where there is no risk of burning yourself.
⚠

Danfoss – 5VUBMA102
1.2 Protection
1.2.1 Corrosion Protection
Due to the risk of corrosion, avoid using different types of sprays in the vicinity of the heat
pump. This particularly applies to:
• Solvents
• Chlorinated cleaning agents
• Paints
• Adhesives

Danfoss – 6 VUBMA102
Expansion valve/
pressure drop
Enclosed
refrigerant
Compressor/
pressure increasing
Brine
Condenser
Evaporator Brine circuit
Refrigerant circuit
Heat transfer fluid
circuit
2 About your heat pump
2.1 Principles of function
A heat pump utilises the energy found in a natural heat source. Simply put, it obtains energy
in the form of heat from a heat source. The heat pump is, therefore, a very environmentally
friendly and economical way of heating a house.
The heat pump has three separate fluid circuits
• Heat transfer fluid circuit – is the circuit that contains the water that transports the heat/
energy to the heating system and the water heater.
• Refrigerant circuit – is the circuit that contains a chlorine and freon free refrigerant that
inside the heat pump, transfers the energy retrieved from the brine circuit through evapo-
ration, compression and condensation, and supplies it to the heat transfer fluid circuit.
• Brine circuit – is the circuit that contains an antifreeze water based mix that obtains and trans-
ports energy from the heat source to the heat pump. This circuit is also known as the collector.
Figure 1: Function principles of a heat pump.
1 A fluid (brine) filled hose is lowered into a lake, buried in the ground or lowered into bedrock.The
brine obtains energy from the heat source by the fluid temperature in the hose being heated a few
degrees by the surrounding heat source.The fluid filled hose is also known as a collector.
2 The brine is guided into the heat pump’s evaporator. The enclosed refrigerant in the
refrigerant circuit is forced to boil as the pressure in the expansion valve drops and
later evaporates to a gas in the evaporator. The energy produced during this process is
released by the slightly heated brine.
3 The refrigerant that now contains a large quantity of energy in the form of heat is trans-
ferred to the compressor, which both increases its temperature and pressure.
4 The refrigerant then continues to the condenser. When condensing, the refrigerant
supplies its heat energy to the heat transfer fluid circuit. The refrigerant’s temperature
decreases and returns to a liquid state.

Danfoss – 7VUBMA102
1
4
3
5
2
5 The heat transfer fluid circuit transports the heat energy out to the water heater, radiator
or the under floor heating system, which heat up.
6 The refrigerant is then transported through the expansion valve where the pressure
drops and the refrigerant starts to boil and then the process starts again.
2.2 Components
The Danfoss heat pump is a complete heat pump installation for heating and hot water. It has
the market’s first compressor developed solely for heat pumps. It has an integrated 180 litre
water heater and auxiliary heating. The water heater uses TWS, which stands for Tap Water
Stratificator, which is technology that results in more effective heat transfer and effective lay-
ering of the water in the water heater.
The Danfoss heat pump is equipped with control equipment, which is controlled via a control
panel.
Heat enters the house via a water borne heating system, a low temperature system. The heat
pump supplies as much of the heat demand as possible before auxiliary heating is engaged
and assists.
The Danfoss heat pump unit consists of five basic units:
1 Heat pump unit
• Scroll compressor
• Stainless steel heat exchanger
• Circulation pumps for brine and heating systems
• Valves and safety equipment for cooling systems and
corresponding electrical components.
2 Water heater
• 180 litres
• Internal anti-corrosion protection with copper or stain-
less steel
• It does not have an anode, which makes it maintenance free
3 Exchange valve
• The heated water either passes through to the heating
system or to the water heater depending on whether
heating or hot water is to be produced
4 Auxiliary heat
• 9 kW electric heating element (DHP-A: 15 kW electric
heating element)
• Electric heating element control in a maximum of three
steps (DHP-A: maximum of five steps)
• Installed on the heating system’s supply pipe
• Covers the demand of extra energy if the heat pump’s
capacity is exceeded
• Automatically connected in the heat pump unit if oper-
ating mode AUTO is selected.

Danfoss – 8 VUBMA102
5 Control equipment
• Control computer with graphic display
• Temperature sensors (outdoor, supply pipe, return pipe, brine in, brine out and hot
water)
• Room sensor (option)
The control equipment controls the heat pup unit’s included components (compressor, circu-
lation pumps, auxiliary heaters and exchange valve) and determines when to start and stop
the pump as well as producing heat for the house or hot water.
2.3 Auxiliary heat, DHP-H, DHP-L, DHP-C
If the heat demand is greater than the heat pump’s capacity, the auxiliary heater engages
automatically. The auxiliary heater is made up of an electric heating element on the supply
pipe that has two outputs, ADD.HEAT 1 and ADD.HEAT 2, and can be controlled in three steps:
• Step 1 = ADD.HEAT 1 = 3 kW
• Step 2 = ADD.HEAT 2 = 6 kW
• Step 3 = ADD.HEAT 1 + ADD.HEAT 2 = 9 kW
To calculate the total energy consumption, see the ”Settings- Calculating energy consump-
tion” section.
In the event of an alarm, the auxiliary heater engages automatically.
2.4 Auxiliary heat, DHP-A
The auxiliary heater is made up of an electric heating element on the supply pipe that has
three outputs, ADD.HEAT 1, ADD.HEAT 2 and ADD.HEAT 3, and can be controlled in five steps:
• Step 1 = ADD.HEAT 1 = 3 kW
• Step 2 = ADD.HEAT 2 = 6 kW
• Step 3 = ADD.HEAT 1 + ADD.HEAT 2 = 9 kW
• Step 4 = ADD.HEAT 2 + ADD.HEAT 3 = 12 kW
• Step 5 = ADD.HEAT 1 + ADD.HEAT 2 + ADD.HEAT 3 = 15 kW
To calculate the total energy consumption, see the ”Settings- Calculating energy consump-
tion” section.
In the event of an alarm, the auxiliary heater engages automatically.
2.5 Water heater, DHP-H, DHP-C
Danfoss heat pumps DHP-H, DHP-C, are supplied with an integrated 180 litre water heater.
The temperature of the hot water cannot be adjusted. Hot water production does not cease
at a determined temperature but when the operating pressure switch reaches its maximum
operating pressure, which corresponds to a hot water temperature of approximately 50-55°C.
Using a regular time interval, the water in the water heater is heated to 60°C to prevent the
build up of bacteria (legion function). The factory set time interval is seven days.
Hot water production is prioritised ahead of heat production, that is, no heat is produced if
there is a hot water demand.

Danfoss – 9VUBMA102
2.6 Water heater, DHP-A
Danfoss DHP-A is supplied with an integrated 180 litre water heater with a defroster tank
outside the water heater that contains the anti-freeze. The difference between DHP-A’s water
heater and other models is the defrost function of the outdoor unit, otherwise they are the
same and have the same functions.
Figure 2: Water heater in DHP-A.
2.7 Regulation information
Heat production - calculating
The indoor temperature is adjusted by changing the heat pump’s heat curve, which is the
control computer’s tool for calculating what the supply temperature should be for water that
is sent out in the heating system. The supply temperature is calculated from the outdoor tem-
perature and two adjustable values: CURVE and ROOM. The lower the outdoor temperature,
the higher the supply temperature. In other words, the supply temperature of the water fed
to the heating system will increase exponentially as the outdoor temperature falls.
The heat curve will be adjusted in connection with installation. It must be adjusted later on,
however, to obtain a pleasant indoor temperature in any weather conditions. A correctly set
heat curve reduces maintenance and saves energy.
1
2
3
4
5
Position Name
1 Hot water line
2 Temperature sensor
3 Defroster tank
4 Water heater
5 TWS coil

Danfoss – 10 VUBMA102
Value for CURVE is 40...
Outdoor temperature
Supply temperature
...at zero degrees
Maximum supply tem-
perature
Supply temperature
Outdoor temperature
Maximum supply tem-
perature
CURVE
The control computer shows the value for CURVE by means of a graph in the display. You can
set the heat curve by adjusting the CURVE value. The CURVE value indicated which supply
temperature the heating system is to have at an outdoor temperature of 0°C.
Figure 3: Graph showing the set value 40 for CURVE.
At outdoor temperatures colder than 0°C, supply water hotter than 40°C is sent out to the
heating system and at outdoor temperatures greater than 0°C, supply water cooler than 40°C
is sent out.
Figure 4: Increasing or reducing the CURVE changes the slope of the curve
If you increase the CURVE value, the heat curve will become steeper and when you reduce it,
it will become flatter.

Danfoss – 11VUBMA102
Supply temperature
Outdoor temperature
Maximum supply tem-
perature
The most energy efficient and cost effective setting is achieved by changing the CURVE value
to adjust the temperature in the house to an even and constant temperature. For a tempo-
rary increase or reduction, adjust the ROOM value instead.
ROOM
If you wish to increase or reduce the indoor temperature, change the ROOM value. The differ-
ence between changing the ROOM value and the CURVE value is that the system’s heat curve
does not become steeper or flatter if the ROOM value is changed, which the curve becomes
if the CURVE value changes, instead the entire heat curve is moved by 3°C for every degree
change of the ROOM value. The reason that the curve is adjusted 3° is that an approximate 3°
increase in supply temperature is needed to increase the indoor temperature 1°.
Figure 5: Changing the ROOM value changes the heat curve upwards or downwards.
The relationship of the supply temperature to outdoor temperature will not be affected. The
supply temperature will be increased or reduced by the same number of degrees all along
the heat curve. that is, the entire heat curve rises or drops instead of the curve gradient
changing.
This method of adjusting the indoor temperatures can only be for a rise or fall.
Sometimes, at outdoor temperatures between -5°C and +5°C, part of the heat curve may
need adjusting if the indoor temperature is not constant. For this reason, the control system
includes a function for adjusting the curve at three outdoor temperatures: -5°C, 0°C, +5°C. If,
for example, the outdoor temperature is -5°C, the supply temperature will change gradually
between 0°C and -10°C, maximum adjustment being reached at -5°C. The figure below shows
the adjusted CURVE -5. The adjustment can be seen in the graph in the form of a bump.

Danfoss – 12 VUBMA102
Supply temperature
Outdoor temperature
Local higher supply tem-
perature at -5°
Figure 6: The adjusted curve at -5°C
You can choose to adjust the heat curve individually at three specified outdoor temperatures:
-5°C, 0°C, +5°C. The supply temperature can be changed by plus/minus 5 degrees.
HEATSTOP
The HEATSTOP function automatically stops all production of heat when the outdoor tem-
perature is equal to, or higher than, the value entered for heat stop.
When the heat stop function is activated, the circulation pump will be turned off - except
when hot water is being produced. The circulation pump will be "exercised" for 1 minute per
day. The factory set value for activating heat stop is an outdoor temperature of 17°C. If the
heat stop function is active, the outdoor temperature must drop 3°C when setting, before the
heat stop stops.
MIN and MAX
The MIN and MAX values are the lowest, respectively highest set point values that are allowed
for the supply temperature.
Adjusting the minimum and maximum supply temperatures is particularly important if your
home has under floor heating.
If your house has under floor heating and parquet floors, the supply temperature must not
exceed the recommendations of the floor manufacturer. Otherwise there is a risk of damaging the
parquet floors. If you have under floor heating and stone tiles, the MIN value should be 22-25°C,
even in summer when no heating is required. Also remember that the value for HEATSTOP needs
adjusting upwards for summer heating. This is to achieve a comfortable floor temperature.
If your house has a basement, the MIN value should be adjusted to a suitable temperature
for the basement in summer. A condition for maintaining the heat in the basement in the
summer is that all radiators have thermostat valves that switch off the heat in the rest of the
house. It is extremely important that the heating system in the house is trimmed correctly,
see the ”Trimming the heating system” section for further information. Also remember that
the value for HEATSTOP needs adjusting upwards for summer heating.

Danfoss – 13VUBMA102
TEMPERATURES
The heat pump can display a graph showing the history of the various sensors’ temperatures
and you can see how they have changed over 100 measurement points in time. The time
interval between the measurement points can be adjusted between one minute and one
hour, factory setting is one minute.
History is available for all sensors, but only the set value is shown in the display for the room
sensor. The integral value that may appear is the heating system’s energy balance.
INTEGRAL
The information below tells you how your heat pump works, there are no values that you as a
customer have to set.
The heat demand in the house depends on the season and weather conditions and is not
constant. The heat demand can be expressed as temperature difference over time and can be
calculated giving an integral value as a result (heat demand). To calculate the integral value,
the control computer uses several parameters.
A heat deficit is needed to start the heat pump, and there are two integral values, A1 and A2,
which start the compressor and auxiliary heater. During heat production, the deficit reduces
and when the heat pump stops, the inertia in the system causes a surplus of heat.
The integral value is a measurement of the surface under the time axis and is expressed in
degree minutes. The figure below shows the factory settings for the integral values that the
heat pump has. When the integral value has reached the set value for INTEGRAL A1, the
compressor starts and if the integral value does not drop but continues to rise, the auxiliary
heater starts when the integral value has reached the set value for INTEGRAL A2.
Figure 7: Starting and stopping heat pump operation based on integral values.
The integral value calculation stops during hot water production and during heat stop.
Integral value calculation resumes two minutes after completed hot water production to give
the heating system time to stabilise the temperature.
Heat surplus
Integral
INTEGRAL A1
Heat surplus
Heating deficit
Compressor
start (-60)
INTEGRAL A2
INTEGRAL A1
INTEGRAL A2
Aux heater
start (-660)
Compressor
stop (≥0)
Aux heater stop
(latest at -60)
Auxiliary
Compressor
No operation No operation
Compressor
start (-60)
Aux heater
start (-660)
Auxiliary heater
Compressor
Time
Heat pump operation
(Heat demand)

Danfoss – 14 VUBMA102
HYSTERESIS
(∆t) ≥ x
Compressor start
(-60)
Compressor stop
(0)
t1
t2
HYSTERESIS
(∆t) ≥ x
TIME
INTEGRAL
SUPPLY TEMP.
HYSTERESIS
The information below tells you how your heat pump works, there are no values that you as a
customer have to set.
In order to start the heat in advance during sudden changes of the heat demand, there is a
value, HYSTERESIS, which controls the difference between the actual supply temperature, t1
and the calculated supply temperature, t2. If the difference is the same or greater than the
set HYSTERESIS value (x), that is, there is a heat demand, or the heat demand disappears,
quicker than the usual integral calculation, the integral value is forced to either the start value
INTEGRAL A1 or to the stop value 0°min.
Figure 8: Conditions for HYSTERESIS to force the integral value to change.

Danfoss – 15VUBMA102
2.8 Installation principle, DHP-H, DHP-C
The image shows the principles of a piping installation with all components.
Figure 9: Principle solution for a piping installation.
Figure 10: Principle solution for a brine installation.
Safety valve
Pressure gauge
Filler tap
HW = Hot water
CW = Cold water
Exp = Expansion
HW Expansion
tank
To
outlet
Supply pipe
Return pipe
Safety valve, 9 bar
cold water
CW Exp
Shut-off valve and
strainer
Safety valve, 3 bar
Bleed and
expansion tank
Filling kit incl.
strainer
Shut-off valve
Strainer
Brine in
Brine out
Flexible hoses

Danfoss – 16 VUBMA102
2.9 Installation principle, DHP-L
The image shows the principles of a piping installation with all components.
Figure 11: Principle solution for a piping installation.
Figure 12: Principle solution for a brine installation.
Supply pipe Return pipe
Connection to any
water heaters
Flexible hoses
Safety valve, 3 bar
Bleed and
expansion tank
Filling kit incl.
strainer
Shut-off valve
Strainer
Brine in
Brine out
Shut-off valve and
strainer
To
outlet
Expansion
tank Pressure gauge
Safety valve

Danfoss – 17VUBMA102
2.10 Installation principle, DHP-A
The image shows the principles of a piping installation with all components.
Figure 13: Principle solution for a piping installation.
Figure 14: Principle solution for a brine installation.
Safety valve, 1.5 bar
Location of the bleed and expan-
sion tank when the outdoor unit
is located at the same level or
lower than the heat pump.
NOTE! The fluid level in the tank
must be above the highest point
of the outdoor unit.
Filling kit incl.
strainer
Shut-off valve
Strainer
Brine in
Brine out
Location of expansion tank, pressure
gauge, and safety valve (1.5 bar) at
pressurised brine circuit when the
outdoor unit is positioned higher
than the heat pump.
Safety valve,
Pressure gauge
Filler tap
HW = Hot water
CW = Cold water
Exp = Expansion
Exp BRINE = Expansion
brine circuit
HW Expansion
tank
To
outlet
Supply pipe
Return pipe
Safety valve, 9 bar
cold water
CW Exp
Shut-off valve and
strainer
Exp BRINE
Flexible hoses

Danfoss – 18 VUBMA102
3 Control computer
A control computer is used to automatically calculate the heat demand in the house where
the heat pump is installed and to ensure that the correct amount of heat is produced and
emitted where necessary. There are many different values (parameters) that must be referred
to during the calculation of the heat demand. Use the control computer to set and change
certain values that have to be adapted according to the house demand.
The display window, keypad and an indicator are on the front of the control computer. It con-
sists of a simple menu system that is used to navigate the desired settings and values.
Figure 15: Display, control buttons and indicator for the heat pump.
Use the four control buttons on the keypad to navigate the menus and increase or reduce the
set values:
• An up button with a plus sign
• A down button with a minus sign
• A right button with a right arrow
• A left button with a left arrow
The display always shows the set ROOM value and the status of the heat pump.
The main menu, INFORMATION, is opened by pressing the left or right buttons. From
INFORMATION one of the four sub-menus can be opened:
OPERAT.; HEATCURVE; TEMPERATURE and OPERAT. TIME.
The symbols in the display are
only examples. Certain sym-
bols cannot be displayed at
the same time.
ROOM 20°C
NO DEMAND HEAT
OPERAT. AUTO

Danfoss – 19VUBMA102
3.1 Display
The display of the control computer shows information about the heat pump’s operation, sta-
tus and any alarms, in text form. The status, indicated by symbols, is also shown in the lower
section which shows the heat pump’s active process.
Operating modes
Appear with applicable heat pump operating status text.
Operating mode Meaning
(OFF) The installation is fully switched off.
Remember that if the operating mode OFF is to be used for
long periods during the winter, the water in the heating sys-
tem in the installation must be drained, otherwise there is a
risk of frost damage.
⚠
AUTO The heat pump and the auxiliary heater are automatically controlled
by the control computer.
HEATPUMP The control computer is controlled so that only the heat pump unit
(compressor) is allowed to operate.
ADD. HEAT The control computer only permits the auxiliary heater to be in opera-
tion. This operating mode can be used when a new installation is
being used, when the brine system is not ready for operation.
HOT WATER In this mode the heat pump only produces hot water, no heat goes to
the heating system.
Symbols
Displays the operating status of the heat pump using symbols.
Symbol Meaning
HP Indicates that the compressor is in operation. An “F” next to the sym-
bol indicates that a flow switch is installed.
Indicates that the auxiliary heater is in operation. Number of auxiliary
power stages indicated by digit.
HOUSE Indicates that the 3-way valve position is for heat production for the
house.
TAP Indicates that the 3-way valve’s position is for hot water production.
VL SYSTEM Indicates the set system VL / D / VL+F / D+F (+F indicates that a flow
switch is installed)
CLOCK Indicates that tariff control is active.

Danfoss – 20 VUBMA102
Symbol Meaning
TANK Indicates the temperature level in the water heater. During charging,
the tank is filled and filling starts at the set start temperature. A light-
ning symbol by the symbol indicates peak heating charging (legion
function).
󰐢
SQUARE Either indicates that the operating pressure switch has deployed, or
that the hot gas temperature has reached its maximum temperature.
Symbols specific to DHP-C
Displays the operating status of the heat pump using symbols.
Symbol Meaning
COOLING Indicates Cooling. A indicates active cooling.
Symbols specific to DHP-A
Displays the operating status of the heat pump using symbols.
Symbol Meaning
DEFROST Displayed if defrosting is active.
FAN Displayed if the fan is active L=Low speed and H= High speed.
Text
Appears with applicable heat pump operating status text.
Message Meaning
ROOM --°C Shows the set ROOM value. Factory setting: 20°C.
If the accessory room sensor is installed it first shows the actual tem-
perature and then the desired indoor temperature within brackets.
ERR PHASE SEQ. Alarm that indicates that there is an incorrect phase sequence to the
compressor. Only display and only the first 10 minutes.
HIGH RETURN Indicates that the high return temperature prevents the compressor’s
operation.
START Indicates that there is a demand for heating production and that no
start delay is active.
EVU STOP Indicates that the additional function EVU is active. This means that the
heat pump compressor and addition are off as long as EVU is active.
NO DEMAND HEAT Indicates that there is no heating production demand.
HIGHPRESS ERROR Alarm that indicates that the high pressure switch has deployed.