Danfoss DHP-AQ Installation Instructions Manual
Installation instructions
DHP-AQ
VMGFD102
If these instructions are not followed during installation and
service, Danfoss A/Sliability according to the applicable warranty
is not binding. Danfoss A/S retains the right to make changes to
components and specifications without prior notice.
© 2010 Copyright Danfoss A/S.
The Swedish language is used for the original instructions. Other
languages are a translation of original instructions.
(Directive 2006/42/EG)
Contents
1 About documents and decals ...................................................... 3
1.1
Introduction .................................................................................... 3
1.2 Symbols in documents ................................................................ 3
1.3 Symbols on decals ........................................................................ 3
1.4 Terminology .................................................................................... 5
2 Important information .................................................................... 6
2.1 General safety precautions ........................................................ 6
2.2 Refrigerant ....................................................................................... 6
2.3 Electrical connection .................................................................... 7
2.4 Water quality ................................................................................... 7
2.5 Commissioning .............................................................................. 8
3 Transport, unpacking and positioning ...................................... 9
3.1 Transporting heat pump ............................................................ 9
3.2 Unpacking heat pump ................................................................ 9
3.3 Positioning the heat pump ........................................................ 9
4 The heat pump ................................................................................ 13
4.1 Dimensions and connections ................................................. 13
4.2 Components ................................................................................. 15
4.3 Principle description .................................................................. 17
4.4 Heating ........................................................................................... 17
4.5 Hot water function ..................................................................... 18
4.6 Defrost function .......................................................................... 19
4.7 Cooling function ......................................................................... 20
4.8 Check and safety functions ..................................................... 21
5 System solution ............................................................................... 24
5.1 System solution DHP-AQ Mini ............................................... 24
5.2 System solution DHP-AQ Midi ............................................... 24
5.3 System solution DHP-AQ Maxi ............................................... 25
5.4 System solution intermediate exchanger .......................... 27
6 Piping installation .......................................................................... 29
6.1 Pipe connection .......................................................................... 29
6.2 Connecting cold and hot water lines .................................. 29
6.3 Connecting the heating system supply and
return lines ..................................................................................................... 29
6.4 Noise and vibrations .................................................................. 30
7 Electrical Installation ..................................................................... 32
7.1 Control centre .............................................................................. 32
7.2 Electrical cabinet in heat pump ............................................. 33
7.3 Cable connection ........................................................................ 33
7.4 Position and connect outdoor sensors ............................... 34
7.5 Connecting supply and return pipe sensors ..................... 34
7.6 Connect hot water sensor to external heater ................... 35
7.7 Connecting circulation pump ................................................ 35
7.8 Connect heating cable driptray ............................................. 35
7.9 Connect the communication cable ...................................... 35
7.10 Connecting the power supply ............................................. 36
8 Operator panel ................................................................................ 37
8.1 Manage operator panel ............................................................ 37
8.2 Operating modes ........................................................................ 38
8.3 Symbols .......................................................................................... 38
8.4 Operational information .......................................................... 39
8.5 Important parameters ............................................................... 39
9 Information menu .......................................................................... 47
9.1 Menu overview ............................................................................ 47
9.2 OPERAT. .......................................................................................... 47
9.3 HEATING ......................................................................................... 47
9.4 DISTRIBUTION CIRCUIT 1 - 2 .................................................... 48
9.5 HOT WATER ................................................................................... 49
9.6 COOLING ........................................................................................ 49
9.7 POOL ................................................................................................ 50
9.8 BUFFER TANK ............................................................................... 50
9.9 OP. DATA ........................................................................................ 51
9.10 OPERAT. TIME ............................................................................ 51
9.11 DEFROST ...................................................................................... 52
9.12 CALENDAR .................................................................................. 52
9.13 ALARM .......................................................................................... 53
9.14 LANGUAGE ................................................................................. 53
10 Service menu ................................................................................. 54
10.1 Menu overview ......................................................................... 54
10.2 HOT WATER ................................................................................ 54
10.3 HEATING ...................................................................................... 55
10.4 COOLING ..................................................................................... 56
10.5 AUX. HEATER .............................................................................. 56
10.6 MANUAL TEST ............................................................................ 57
10.7 INSTALLATION ........................................................................... 58
10.8 DEFROST ...................................................................................... 60
10.9 OPTIMUM .................................................................................... 61
10.10 BUFFER TANK .......................................................................... 62
11 Commissioning ............................................................................. 65
11.1 Filling and bleeding the hot water heater
and heating system ..................................................................................... 65
11.2 Checking the pipes and electrical installation ............... 65
11.3 Configuration of control system ......................................... 66
11.4 Manual test ................................................................................. 67
11.5 Start-up and commissioning ................................................ 69
11.6 Installation protocol ................................................................ 70
11.7 Customer information ............................................................ 70
12 Technical data ............................................................................... 71
12.1 Working range compressor operation ............................. 73
VMGFD102 – 1
www.documentation.heatpump.danfoss.com
1 About documents and decals
1.1
Introduction
The following documents are available for this product:
Installation instructions containing information to install and commission a heat pump installation, and infor-
•
mation about the heat pump’s function, accessories and technical data. Supplied with the heat pump on delivery.
Service instructions that contain information about fault tracing. The service instructions are available for
•
download as below.
The electrical instructions that contain the wiring diagram for the heat pump intended for fault tracing and
•
service. The electrical instructions are available for download as below.
The maintenance instructions must handed over and gone through with the end customer. Supplied with the
•
heat pump on delivery.
Country specific instructions and forms are available where relevant. Supplied with the heat pump on delivery.
•
Sheet with adhesive decals that will be used as translation for the existing English language type plates.
•
The Service instructions and Electrical instructions are available for download here:
1.2 Symbols in documents
The instructions contain different warning symbols, which, together with text, indicate to the user that there are
risks involved with actions to be taken.
The symbols are displayed to the left of the text and three different symbols are used to indicate the degree of
danger:
DANGER! Indicates an immediate danger that leads to fatal or serious injury if necessary measures are not
taken.
Warning! Risk of personal injury! Indicates a possible danger that can lead to fatal or serious injury if
necessary measures are not taken.
Caution! Risk of installation damage. Indicates a possible hazard that can lead to item damage if necessary
measures are not taken.
A fourth symbol is used to give practical information or tips on how to perform a procedure.
Note! Information regarding making the handling of the installation easier or a possible operational
technical disadvantage.
1.3 Symbols on decals
The following symbols can occur on decals on the different parts of the heat pump. Which symbols are used
depends on the heat pump model.
Installation instructions VMGFD102 – 3
!
!
406
Warning symbols
Warning, danger!
Read the documentation provided.
Read the documentation provided.
Warning, hazardous electrical voltage!
Warning, hot surfaces!
Warning, moving parts!
Warning, risk of crushing injury!
Electrical components
Component, normal Component, accessory
3 Outdoor unit 362 Shunt valve
50 Outdoor sensor 363 Exchange valve hot water
54 Hot water sensor 365 Supply line sensor
55 Sensor hot-water top 366 Return line sensor
71 Flow sensor 406 Room sensor
304 Circulation pump 408 EVU
353 Drip tray 417 Defrost sensor
Example:
Room sensor
4 – Installation instructions VMGFD102
Pipe connections
Bleeding
Defrosting tank
Expansion tank with safety valve, brine
Brine
Temperature and pressure relief valve
1.4 Terminology
Term Meaning
Heating system/Heat transfer fluid
circuit
Supply line The heating system’s supply line with flow direction from the heat pump to radiators/
Return line The heating system’s return line with flow direction from radiators/under floor heating
Circulation pump Circulation pump for heating system.
Refrigerant circuit The energy carrying circuit between the outdoor air and heating system.
Refrigerant The gas/liquid that circulates in the refrigerant circuit.
Tap water
Outdoor unit
Water heater
Heating system
The circuit that generates heat to the property or to the water heater.
under floor heating or water heater.
or water heater to the heat pump.
Installation instructions VMGFD102 – 5
2 Important information
2.1
General safety precautions
Warning! Risk of personal injury! Children are not permitted to play with the product.
Caution! The heat pump must be installed by authorised installation engineers and the installation must
follow the applicable local rules and regulations as well as these installation instructions.
Caution! This product is not intended for persons (including children) with reduced physical, sensory or
psychological capacity, or who do not have knowledge or experience, unless supervised or they have
received instructions on how the apparatus functions from a safety qualified person.
Caution! When cooling it is important to limit the lowest flow line temperature to prevent condensation.
2.2 Refrigerant
2.2.1
2.2.2 Toxicity
2.2.3 Work on the refrigerant circuit
Fire risk
The refrigerant is not combustible or explosive in normal conditions.
In normal use and normal conditions the refrigerant has low toxicity. However, although the toxicity of the refrigerant is low, it can cause injury (or be highly dangerous) in abnormal circumstances or where deliberately abused.
Warning! Risk of personal injury! Spaces in which heavy vapour can collect below the level of the air must
be well ventilated.
Refrigerant vapour is heavier than air and, in enclosed spaces below the level of a door for example, and in the
event of leakage, concentrations can arise with a resultant risk of suffocation due to a lack of oxygen.
Warning! Risk of personal injury! Refrigerant exposed to a naked flame creates a poisonous irritating gas.
This gas can be detected by its odour even at concentrations below its permitted levels. Evacuate the area
until it has been sufficiently ventilated.
Caution! Work on the refrigerant circuit must only be carried out by a certified engineer!
Caution! When repairing the refrigerant circuit, the refrigerant must not be released from the heat pump it must dealt with in the appropriate way.
6 – Installation instructions VMGFD102
Refilling must only be carried out using new refrigerant (for the amount and type of refrigerant see manufacturer’s
plate) through the service valves.
Caution! All warranties from Danfoss are void if, when filling with refrigerant other than Danfoss A/S
specified refrigerant, if there has not been written notification that the new refrigerant is an approved
replacement refrigerant together with other remedies.
2.2.4 Scrapping
Caution! When the heat pump is to be scrapped the refrigerant must be extracted for disposal. Local rules
and regulations related to the disposal of refrigerant must be followed.
2.3 Electrical connection
DANGER! Hazardous electrical voltage! The terminal blocks are live and can be highly dangerous due to
the risk of electric shock. All power supplies must be isolated before electrical installation is started. The
heat pump is connected internally at the factory, for this reason electrical installation consists mainly of
the connection of the power supply.
Warning! Electrical installation may only be carried out by an authorised electrician and must follow
applicable local and national regulations.
Warning! The electrical installation must be carried out using permanently routed cables. It must be
possible to isolate the power supply using a multi-pole circuit breaker with a minimum contact gap of 3
mm.
2.4 Water quality
Caution! A normal heating system always contains a certain amount of corrosion particulates (rust) and
sludge products from calcium oxide. This comes from acid that is naturally occurring in the fresh water
that the system is filled with. It is not good practice to have to fill the heating system regularly which is
why any leakage in the heating system should be repaired immediately. Normal filling should occur only
once or twice a year. The water in the heating system should be as clean as possible, always position the
dirt filter on the return line from the heating system to the heat pump, as close to the heat pump as
possible.
Caution! Hard water; Normally it is not a problem installing a heat pump in areas with hard water because
the normal operating temperature for the hot water does not exceed 60°C. In areas where there are
exceptional prevailing conditions with the water one can install a softening filter, which softens the water,
cleans any impurities and prevents the build up of calcification.
Installation instructions VMGFD102 – 7
2.5 Commissioning
Caution! The installation may only be commissioned if the heating system is filled and bled. Otherwise the
circulation pump can be damaged.
Caution! If the installation is only to operate using an auxiliary heater during the installation, ensure that
the heating system is filled and bled and that the compressor cannot be started. This is carried out by
setting the operating mode to AUX. HEATER.
8 – Installation instructions VMGFD102
3 Transport, unpacking and positioning
3.1
Transporting heat pump
Caution! The heat pump must always be transported and stored standing and in a dry environment. If the
heat pump is laid on the incorrect side it may become seriously damaged as the oil in the compressor can
run out in the pressure pipe and therefore prevent normal function.
Caution! Always secure the heat pump so that it cannot tip over during transportation.
3.2 Unpacking heat pump
3.2.1
Delivery check
1. Check that there is no transport damage.
Remove the packaging and check that the delivery contains the following components.
2.
Table 1. Supplied contents
Quantity Name
1 Heat pump
1 Control unit
1 Document set
1 Package (1 x shut-off valve with filter, 1 x outdoor sensor)
3.3 Positioning the heat pump
3.3.1
Recommended location
When positioning the heat pump, note the following:
Caution! The heat pump must be positioned outdoors on a stable base. The floor must be able to support
the gross weight of the heat pump. (see Technical data)
Caution! The heat pump must be secured on a stable base, for example a cast foundation. All four
mounting points must be secured to the base.
Installation instructions VMGFD102 – 9
100 mm
~900 mm
b
c
a
7
5
4
3
6
1
8
2
Position Description
a Drainage hole
b Foundation
c Gravel
Meas-
6-9 kW 11-13 kW 16-18 kW
urements
1 450 mm 470 mm 710 mm
2 424 mm 480 mm 480 mm
3 618 mm 672 mm 857 mm
4 130 mm 190 mm 145 mm
5 61 mm 65 mm 65 mm
6 ~1,000 mm ~1,200 mm ~1300 mm
7 ~650 mm ~720 mm ~720 mm
8 Ø 65 mm Ø 65 mm Ø 65 mm
Bolt size
6-9 kW 11-13 kW 16-18 kW
M10 (4x) M12 (4x) M12 (4x)
10 – Installation instructions VMGFD102
Caution! A driptray is installed with the purpose of gathering and draining away melt water during
defrosting. Connect a hose or pipe along with a heat trace cable between the outlet of the drip tray and a
drain or a free draining piece of ground. The heat cable must be connected to the terminal provided and
is necessary to prevent ice blockage.
Caution! Check with a spirit level that the heat pump is installed horizontally.
Caution! Incorrect positioning of the heat pump risks reduction of performance.
Caution! The unit with water heater must be placed indoors, in an area with a floor drain.
Caution! The unit with water heater must be placed indoors, on a stable surface. The floor must be able to
support the gross weight of the unit with filled water tank (see Technical data).
Note! Avoid placing the heat pump near windows or walls to noise sensitive areas.
Note! Ensure that there is sufficient distance to neighbouring properties so that they are not exposed to
noise. Applicable local regulations must be followed.
Note! The heat pump should not be enclosed.
Note! Keep the heat pump and its immediate area free of snow, ice, leaves etc.
Note! Remember that the heat pump must have a certain amount of space in order to function and for
servicing. Otherwise there is a risk that the air will recirculate from exhaust to intake. Avoid this by
following the dimensions given below.
Installation instructions VMGFD102 – 11
>
2
0
0
0
m
m
>
2
0
0
0
m
m
>1500
m
m
>
300
m
m
>
2
000
mm
1
3.3.2 Lifting instructions
To lift the heat pump into position, unscrew the side plates by slackening off the screws (1).
Then use the side members behind the side panels to lift and position the heat pump.
12 – Installation instructions VMGFD102
33
5
4
6
1
2
600
380
204
1
4 The heat pump
4.1
Dimensions and connections
Position Description 6-9 kW 11-13 kW 16-18 kW
1 Width 856 mm 1,016 mm 1,166 mm
2 Depth 510 mm 564 mm 570 mm
3 Height 1,272 mm 1,477 mm 1,557 mm
4 Height to supply line pipe, 28 mm Cu 155.5 mm
5 Height to return line pipe, 28 mm Cu 96.5 mm
6 Length max protruding pipe 30 mm
Control unit DHP-AQ Mini
Position Description
1 Lead-in for supply, sensor and communication cables
Control unit DHP-AQ Midi
Installation instructions VMGFD102 – 13
675
420
255
1
2
3
4
1845 ±10
596
455
690
1
2
3
4
5
125
210
330
6
7
8
9
10
Control unitDHP-AQ Maxi
Position Description
1 Supply line for heating system,
28 mm Cu
2 Supply line to water heater,
28 mm Cu
3 Supply line from heat pump,
28 mm Cu
4 Lead-in for supply, sensor and communication cables
Position Description
1 Supply line heating system,
28 mm Cu
2 Return line heating system,
28 mm Cu
3 Connection for bleed valve,
22 mm Cu
4 Hot water line,
22 mm Cu
5 Cold water line,
22 mm Cu
6 Lead-in for supply, sensor and communica-
tion cables
7 Supply or return line heat pump
8 Supply or return line heat pump
9 Extra knock-out
10 Safety valve for temperature and pressure
(only applies to certain models)
14 – Installation instructions VMGFD102
Position 7 and 8 can be connected to either the left or righthand side or bottom of the control unit.
11
10
12
13
14
16
15
17
1
2
3
4
5
6
7
8
9
19
18
4.2 Components
4.2.1
Outdoor unit
Position Name Position Name
1 Electrical cabinet 11 Electronic expansion valve
2 Fan 12 Receiver
3 Pressure transmitter 13 Drying filter
4 Suction line 14 Heat exchanger
5 Compressor 15 Flow sensor
6 High pressure switch 16 Heating system supply line
7 Operating pressure switch 17 Return line heating system
8 Four-way valve 18 Solenoid
9 Discharge pipe 19 Non-return valve
10 Air heat exchanger
Installation instructions VMGFD102 – 15
4.2.2 Indoor unit
1
1
2
4
3
5
1
2
3
4
DHP-AQ Mini
DHP-AQ Midi
DHP-AQ Maxi
Position Description
1 Control module (transparent in image)
2 Immersion heater
3 Reversing valve
4 Circulation pump
5 Water heater
4.2.3 Speed controlled fan
The fan is operated by a permanent solenoid motor with great efficiency. The fan starts at a nominal speed, which
differs depending on the size of output. The fan speed is adjusted up or down as required which is determined by
the temperatures in the refrigerant circuit.
4.2.4 Electronic expansion valve
When the refrigerant passes the expansion valve the pressure and temperature of the refrigerant are reduced. In
this way the energy in the outdoor air is available to the refrigerant circuit. By regulating the opening degree of
the expansion valve one can optimise the flow in the refrigerant circuit in different operating conditions. Control
of the electronic expansion valve is based on the measurements of temperatures and pressures in the refrigerant
circuit and outside air.
4.2.5 Auxiliary heat
An auxiliary heater is included in DHP-AQ Midi and DHP-AQ Maxi and consists of an immersion heater, which is
located on the supply line ahead of the reversing valve. An immersion heater is available for DHP-AQ Mini as an
accessory. Also see System solution, Page 24, pos 114.
Immersion heaters in the DHP-AQ series intended for 400V supply voltage have three heating elements and can be
controlled in five power stages. Products for 230V have two heating elements and are controlled in three power
stages.
The parameter MAX STEP determines the number of power stages the immersion heater can be controlled to. The
two stages 4 and 5 cannot be engaged when the compressor is in operation as opposed to stages +4 and +5
where it is possible.
With an internal immersion heater which is controlled by several power stages an external auxiliary heater, for
example an electric boiler, can be controlled using the potential free output 101.8 – 101.16.
If an immersion heater of a different type is used that requires a start signal in DHP-AQ Mini (placed before the hot
water reversing valve) the auxiliary heater is controlled from the potential free output 101.8 – 101.16. The parameter MAX STEP is set to ”P”.
16 – Installation instructions VMGFD102
In the event of power cuts longer than three minutes, only a 6 kW output will be connected immediately after
power has returned, the remaining output is delayed two hours.
4.2.6 Compressor heater
The compressor heater runs in intervals when the outdoor temperature falls below 10°C. The compressor heater
does not run at the same time as the compressor.
4.3 Principle description
A heat pump utilises the renewable energy from the sun and that is also found in a natural heat source, such as
rock, ground, lakes, ground water or air. The heat pump can be compared to a reversed refrigerator; in a refrigerator heat is transferred from the inside of the refrigerator to the outside, whereas in a heat pump, the solar energy
that is stored in a heat source is transferred to the inside of the house. In both a refrigerator and heat pump the
process is driven by an electrically powered compressor. The heat pump uses the solar energy in the heat source
and gives off two to three times more heat energy than it uses in electrical energy. The heat pump is, therefore, a
very environmentally friendly and economical way of heating a house.
4.4 Heating
The heat pump produces heating (see figure below).
When the compressor (1) receives a start signal the refrigerant is compressed in gas form via the 4 way valve (5) to
the plate heat exchanger (7). The hot refrigerant gives off heat through the plate heat exchanger (7) to the heating
system (8) and transfers to liquid phase. The refrigerant continues through the drying filter (10) and the electronic
expansion valve (11) to the air exchanger (15). In the air exchanger (15) the refrigerant is heated to gas form by the
hotter outdoor air. The gas continues via the 4 way valve (5) back to the compressor (1).
Installation instructions VMGFD102 – 17
3
2
1
1918
17
15
14
16
11
13
12
10
9
8
7 6
5
4
Position Description Position Description
1 Compressor 11 Electronic expansion valve
2 Operating pressure switch 12 Non-return valve
3 High pressure switch 13 Solenoid
4 Discharge pipe sensor 14 Refrigerant sensor 2
5 Four-way valve 15 Air exchanger (evaporator)
6 Heating system (cold return line) 16 Fan
7 Plate heat exchanger (condenser) 17 Refrigerant sensor 1
8 Heating system ( hot supply line) 18 Pressure transmitter
9 Receiver 19 Temperature transmitter
10 Drying filter
The heat pump can produce heat for heating (house, pool), hot water and cooling. The hot water requirement is
prioritised before the heating requirement and cooling requirement. The heating requirement is calculated from
outdoor temperature and set heat curve.
For a fuller description of heat curves etc., seeImportant parameters, Page 39.
4.5 Hot water function
The water heater is equipped with a TWS coil (Tap Water Stratificator). The hot water is led from the heat pump
through the water heater in the TWS coil from the top down. In this way the upper section of the water heater,
where the hot water is tapped from, is always heated first.
Heating the hot water in the water heater is not stopped by the temperature but via the pressure in the refrigerant
circuit of the heat pump unit. The operating pressure switch on the pressure pipe breaks at 28.5 bar. This means
that heat pumps in different output classes may have slightly different peak temperatures for hot water. As a rule
the peak temperature is between 54 – 58°C in a 180-litre water heater. Thanks to the design of the water heater
and the TWS coil the hot water layers itself so that the hottest water is always at the top of the water heater and
the cooler water at the bottom.
Two sensors indicate the present temperature of the hot water to the heat pump controls. A top water sensor that
is located in the top of the water heater, and a hot water sensor located approx 50 cm up from the bottom of the
water heater. Both the sensor values are ”weighted” where the hot water sensor influence is 65 % (factory setting,
18 – Installation instructions VMGFD102
3
2
1
1918
17
15
14
16
11
13
12
10
9
8
7 6
5
4
can be changed if necessary). This means that if the start value for hot water production is set to 40°C the heat
pump need not necessarily start hot water production when the hot water sensor displays 40°C but also makes
reference to what temperature the peak water sensor displays. If it is still very hot at the top of the water heater
the start of hot water production will be delayed.
With anti-legionella operation, when the immersion heater heats the water heater to 60°C to prevent growth of
legionella bacteria, the peak water sensor temperature has no impact, only the hot water sensor has control. Antilegionella is factory set as top heating interval every 7th day.
4.6 Defrost function
The heat pump defrosts (see figure below).
Note! The designations for condenser and evaporator are switched during the defrost function (like the
cooling function) compared to the heating function, because the designations follow the cooling
technical function that respective units have (evaporation respectively condensing).
When the compressor (1) receives a start signal the refrigerant is compressed in gas form via the 4 way valve (5) to
the air exchanger (15). The hot refrigerant gives off heat to the air exchanger (15), shifts to liquid phase and continues to the plate heat exchanger (7). In the plate heat exchanger (7) the refrigerant is heated to gas form by the
hotter heating system (6). The heating system is cooled. The refrigerant continues via the 4 way valve (5) back to
the compressor (1).
Position Description Position Description
1 Compressor 11 Electronic expansion valve
2 Operating pressure switch 12 Non-return valve
3 High pressure switch 13 Solenoid
4 Discharge pipe sensor 14 Refrigerant sensor 2
5 Four-way valve 15 Air exchanger (condenser)
6 Heating system (hot return line) 16 Fan
7 Plate heat exchanger (evaporator) 17 Refrigerant sensor 1
8 Heating system ( cold supply line) 18 Pressure transmitter
Installation instructions VMGFD102 – 19
3
2
1
1918
17
15
14
16
11
13
12
10
9
8
7 6
5
4
Position Description Position Description
9 Receiver 19 Temperature transmitter
10 Drying filter
Defrosting is initiated by low temperature in the refrigerant circuit after the air exchanger and, among other
things, is dependent on outdoor temperature, humidity and operating time. The length of defrosting varies
depending on the extent of freezing of the air exchanger. Defrost continues until the air heat exchanger is free of
ice and the temperature after the air exchanger has risen to the desired temperature. After completed defrosting
the heat pump returns to the operating mode before defrosting.
During defrosting the heat pump retrieves energy from the house's heating system. The water volume in the heating system can be increased by installing a buffer tank. The buffer tank can also act as a surge tank.
4.7 Cooling function
The heat pump produces cooling (see figure below).
The refrigerant process is similar to that at the defrosting function.
Note! The designations for condenser and evaporator are switched during the cooling function (like the
defrosting function) compared to the heating function, because the designations follow the cooling
technical function that respective units have (evaporation respectively condensing).
When the compressor (1) receives a start signal the refrigerant is compressed in gas form via the 4 way valve (5) to
the air exchanger (15). The hot refrigerant gives off heat to the air exchanger (15), shifts to liquid phase and continues to the plate heat exchanger (7). In the plate heat exchanger (7) the refrigerant is heated to gas form by the
hotter heating system (6). The heating system is cooled. The refrigerant continues via the 4 way valve (5) back to
the compressor (1).
Position Description Position Description
1 Compressor 11 Electronic expansion valve
2 Operating pressure switch 12 Non-return valve
3 High pressure switch 13 Solenoid
20 – Installation instructions VMGFD102
1
3
6
5
7
8
4
9
2
10
Position Description Position Description
4 Discharge pipe sensor 14 Refrigerant sensor 2
5 Four-way valve 15 Air exchanger (condenser)
6 Heating system (hot return line) 16 Fan
7 Plate heat exchanger (evaporator) 17 Refrigerant sensor 1
8 Heating system ( cold supply line) 18 Pressure transmitter
9 Receiver 19 Temperature transmitter
10 Drying filter
Cooling function is started by the heat pump control unit and is primarily temperature controlled. If the hot water
heater is installed the control unit will alternate between cooling and hot water production with prioritisation for
the hot water requirement.
4.8 Check and safety functions
The heat pump has a number of check and safety functions to protect the installation against damage during
abnormal operating conditions.
The diagram below shows the heat pump's circuits with respective safety functions.
Symbol explanation
1 Heat transfer fluid circuit
2 Flow sensor
3 Safety valve, heat transfer fluid circuit, externally mounted
4 Refrigerant circuit
5 Operating pressure switch
6 High pressure switch
7 Pressure transmitter
8 Compressor
9 Fan
10 Discharge pipe sensor
Heat transfer fluid circuit (1)
If the flow in the heat transfer fluid circuit is below the permitted value at heat pump start and before the defrosting blocks the flow sensor (2) heat pump's normal operation, an alarm indicator on the control unit control panel
flashes and a warning text appears in the display of the control panel. The alarm resets itself when the flow
returns.
If the pressure in this circuit exceeds the opening pressure for the safety valve (3), the valve opens, releases the
overpressure and closes again. The safety valve overflow pipe must have an open connection to the drain and
visibly flow into this in a frost-free environment.
Refrigerant circuit (4)
The refrigerant circuit's high pressure side is equipped with a high pressure switch (6) and an operating pressure
switch (5).The operating pressure switch stops the compressor when the operating pressure is reached.
If the operating pressure switch does not work and the pressure continues to increase in the circuit, the high pressure switch activates when its break pressure is reached, whereupon the compressor stops and the heat pump's
normal operation is blocked.
If the high pressure switch is activated an alarm indicator flashes on the control unit's control panel and a warning
text appears in the display of the control panel. The blocked heat pump is reset by setting the operating mode to
OFF and then back to the previously selected mode.
Installation instructions VMGFD102 – 21
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