Gebwell GEMINI 40 User manual

Installation, Operation and
Maintenance Manual
GEMINI Heat Pump
WWW.GEBWELL.FI

2 Gebwell Gemini Installation, operation, and maintenance manual
Table of contents
1WARRANTY............................................................................................................................................................................. 5
2INSTALLATION RECORD .................................................................................................................................................... 7
3HEAT PUMP OPERATING INSTRUCTIONS ..................................................................................................................... 8
3.1General ....................................................................................................................................................................................... 8
3.2Ground source heat energy ......................................................................................................................................................... 8
3.3Ground source cooling ............................................................................................................................................................... 8
3.4Heat pump’s operating principle ................................................................................................................................................ 8
3.5Heating functions ....................................................................................................................................................................... 9
3.6Tips for saving ............................................................................................................................................................................ 9
4DELIVERY AND HANDLING ............................................................................................................................................ 10
4.1Delivery contents ...................................................................................................................................................................... 10
4.2Optional accessories ................................................................................................................................................................. 10
4.3Storage...................................................................................................................................................................................... 1 0 
4.4Transport .................................................................................................................................................................................. 10
4.5Removal from package and transport to final installation location ........................................................................................... 10
4.6Safety instructions .................................................................................................................................................................... 10
4.7Heat pump’s location ................................................................................................................................................................ 11
4.8Mounting and unmounting the upper compressor unit ............................................................................................................. 11
5HEAT PUMP STRUCTURE ................................................................................................................................................. 12
5.1GEMINI structure..................................................................................................................................................................... 12
5.2Sensors ..................................................................................................................................................................................... 1 3 
5.3Pumps ....................................................................................................................................................................................... 1 3 
5.4Control valves .......................................................................................................................................................................... 13
5.5Other controls ........................................................................................................................................................................... 13
6DIMENSIONS AND PIPE CONNECTIONS ....................................................................................................................... 14
6.1Heat pump connections ............................................................................................................................................................ 14
6.2Pipe connections ....................................................................................................................................................................... 14
7PIPE INSTALLATION .......................................................................................................................................................... 15
7.1Collector ................................................................................................................................................................................... 1 5 
7.2Charging circuit ........................................................................................................................................................................ 16
7.3Connections of an additional heat source ................................................................................................................................. 18
7.4Extraction air heat recovery ...................................................................................................................................................... 18
7.5Connections for external fixed fuel burners ............................................................................................................................. 18
7.6Connecting of domestic hot water system ................................................................................................................................ 18
8ELECTRICAL CONNECTIONS .......................................................................................................................................... 20
8.1General ..................................................................................................................................................................................... 2 0 
8.2Power supply ............................................................................................................................................................................ 20
8.3Compressor’s motor protection switches (F1 and F2) .............................................................................................................. 20
8.4Phase sequence / soft starter ..................................................................................................................................................... 20
8.5Connection of temperature sensors ........................................................................................................................................... 20
8.6Connection of the domestic hot water charging package (HWExE) ......................................................................................... 21
8.7Connection of domestic hot water mixing valve (HWEx) ........................................................................................................ 21
8.8Control of electric heaters in the accumulator / sequence controlled additional heating .......................................................... 21
8.9Change-over valve(s) ............................................................................................................................................................... 22
8.10Heating circuits ........................................................................................................................................................................ 22
8.11Domestic hot water’s circulation pump .................................................................................................................................... 23
8.12Connection of external source pump ........................................................................................................................................ 23
8.13Connection of room unit, QAA74 ............................................................................................................................................ 23
8.14Room sensor (acceossory) QAA55. ......................................................................................................................................... 23
8.15Alarm forwarding ..................................................................................................................................................................... 23
8.16Call for heating 0-10V .............................................................................................................................................................. 23
8.17External prevention of activation / release signal ..................................................................................................................... 23
8.18Tariff control ............................................................................................................................................................................ 24
8.19Installation of extension module ............................................................................................................................................... 24
8.20Connection of a cascade connection ......................................................................................................................................... 24
8.21Connection of additional heat source ....................................................................................................................................... 24
9FILLING AND VENTING ..................................................................................................................................................... 25
9.1Heating system ......................................................................................................................................................................... 25
9.2Filling the collector, non-pressurised ....................................................................................................................................... 25
9.3Pressure test of the collector ..................................................................................................................................................... 25

v1-6 29082018 3
9.4Venting of the collector’s horizontal piping ............................................................................................................................. 25
9.5Cleaning the collector filter ...................................................................................................................................................... 26
10ACTIVATING THE HEAT PUMP ...................................................................................................................................... 26
10.1Before activation ...................................................................................................................................................................... 26
10.2Activation ................................................................................................................................................................................. 26
10.3Venting ..................................................................................................................................................................................... 2 7 
10.4Venting the heat supply circuit ................................................................................................................................................. 28
10.5Use without a collector and use during construction site ......................................................................................................... 28
10.6Activation of a cascade system ................................................................................................................................................ 28
11HEAT PUMP OPERATION .................................................................................................................................................. 29
11.1User interface ........................................................................................................................................................................... 29
11.2User terminal ............................................................................................................................................................................ 29
11.3Display symbols ....................................................................................................................................................................... 29
11.4User levels ................................................................................................................................................................................ 30
11.5Heating settings ........................................................................................................................................................................ 30
11.6Selecting heating mode ............................................................................................................................................................ 31
11.7Domestic hot water settings ..................................................................................................................................................... 31
11.8Heat pump’s Reset function ..................................................................................................................................................... 31
12SITE-SPECIFIC DEFINITION ............................................................................................................................................ 32
12.1Time and date ........................................................................................................................................................................... 32
12.2Summer/winter switch connection ........................................................................................................................................... 32
12.3Language selection ................................................................................................................................................................... 32
12.4Time programs ......................................................................................................................................................................... 32
12.5Heating area (Heating circuit) .................................................................................................................................................. 32
12.6Domestic hot water .................................................................................................................................................................. 34
12.7Domestic hot water circulation pump ....................................................................................................................................... 35
12.8Cooling circuit .......................................................................................................................................................................... 35
12.9Heat pump settings ................................................................................................................................................................... 37
12.10Programming the reservoir’s resistors and output water’s electrical heaters ............................................................................ 38
12.11Control of additional heat source ............................................................................................................................................. 39
12.12Control of fixed fuel burner...................................................................................................................................................... 40
12.13Call for heating (VAK control) ................................................................................................................................................ 40
12.14ModBus communication .......................................................................................................................................................... 41
13SYSTEM INFO ....................................................................................................................................................................... 41
13.1Special situations ...................................................................................................................................................................... 41
13.2Heat pump status ...................................................................................................................................................................... 41
13.3Heating circuits’ status information ......................................................................................................................................... 42
13.4Domestic hot water status information ..................................................................................................................................... 42
13.5Measurements .......................................................................................................................................................................... 42
14FAILURES .............................................................................................................................................................................. 44
14.1Alerts ........................................................................................................................................................................................ 44
14.2Troubleshooting ....................................................................................................................................................................... 44
14.3Troubleshooting table ............................................................................................................................................................... 46
15MAINTAINING AND SERVICING THE HEATPUMP .................................................................................................... 49
15.1Maintenance notice .................................................................................................................................................................. 49
15.2Inspections ............................................................................................................................................................................... 49
15.3Nominal curves of sensors ....................................................................................................................................................... 49
15.4Testing inputs and outputs ........................................................................................................................................................ 49
16TECHNICAL SPECIFICATIONS ........................................................................................................................................ 51
17CONNECTION POINTS, CONTROLLER 1: ..................................................................................................................... 53
17.1Sensors ..................................................................................................................................................................................... 5 3 
17.2Controls .................................................................................................................................................................................... 5 4 
18SETPOINT EXAMPLES FOR HEAT PUMP ADJUSTMENTS IN DIFFERENT HEATING NETWORKS .............. 55
19MAINTENANCE RECORD .................................................................................................................................................. 56
20ENERGY LABELS................................................................................................................................................................. 57
LIITE 1: ELECTRICAL DIAGRAMS
LIITE 2: DECLARATION OF CONFORMITY

4 Gebwell Gemini Installation, operation, and maintenance manual
ALWAYS KEEP THE OPERATING MANUAL IN THE IMMEDIATE VICINITY OF THE DEVICE!
Carefully study the manual before installing, adjusting or maintaining the device. Observe the instructions provided. Request a technician
to fill out the Commissioning and Warranty Protocoll, which must be returned to the device manufacturer. The protocoll is a requirement
for maintaining the validity of the manufacturer’s warranty.
Fill out the information below. This information must be available if the device experiences any failures.
Model: Serial number:
HVAC company: Name:
Date: Tel.:
Electrician: Name:
Date: Tel.:

v1-6 29082018 5
1 WARRANTY
Gebwell Ltd.
Patruunapolku 5, 79100 LEPPÄVIRTA, tel [phone], [e-mail]
issues the product,
GEMINI heat pump
a warranty regarding manufacturing and material faults, with the following contents.
Warranty period and start date
A two- (2) year warranty will be issued to this product, counting
from the product delivery date.
Two copies of the commissioning and warranty protocol will be
delivered with the heat pump. The installer / reseller of the heat
pump fills the said protocol in and goes over it with the customer.
Both Parties confirm they have gone over the protocol, and ac-
cept the terms of warranty with their signature. The customer’s
copy of the warranty protocol must be stored, and presented on
request. The other copy must be delivered to the factory within
1 month from the product commissioning date. The warranty is
not valid in case the commissioning and warranty protocol has
not been filled in correctly, or if the factory copy has not been
returned to the factory.
Warranty contents
The warranty extends to all manufacturing and raw material
faults that have occurred in this product during the warranty pe-
riod, as well as the direct expenses related to the changing of
these devices.
The buyer is responsible for any device malfunctions caused by
the storage conditions between the delivery and commissioning
date (cf. installation, operating and maintenance manual;
storage).
5-year component warranty
In addition to the normal product warranty, a five- (5) year com-
ponent warranty will be issued to the heat plate exchangers, start-
ing from the product delivery date.
The component warranty does not extend to the direct or indirect
expenses caused by the changing of a component. Otherwise, all
terms and limitations of the product warranty apply for the com-
ponent warranty, as well.
Warranty limits
The warranty does not extend to the expenses (travel, power con-
sumption, etc.) caused by a malfunctioning device, the buyer’s
production loss, loss of earnings or other indirect expenses.
This warranty has been given on the condition that the product
is working in normal operating conditions, and that the operating
instructions are followed carefully. The liability of the guarantor
is limited according to these terms and conditions, and the war-
ranty does not extend to such damage as the product may cause
to another item or person.
The warranty does not extend to direct personal injuries or dam-
age to property caused by the delivered product.
The warranty presupposes that the installation has followed all
valid regulations, generally accepted methods of installation and
installation instructions given by the manufacturer of the prod-
uct.
The warranty does not extend to or is not valid in case the prod-
uct is used in any other way than required by the sizing.
The customer is obliged to perform a visual check on the product
before the installation, and it is not allowed to install a product
that is clearly faulty
The warranty does not cover malfunctions, which have been
caused by
 the transportation of the product
 the carelessness of the product operator, the overload
of the product, the failure of adhering to the operating
instructions or maintenance
 circumstances beyond the guarantor’s control, such
as voltage fluctuations (the maximum range of volt-
age fluctuations is +/- 10%), lightning, fire or acci-
dents other than those caused by the repair work,
maintenance or structural changes done by authorised
resellers
 product installation or positioning on the operating
site, which is in contradiction with the installation,
operating and maintenance manual, or otherwise in-
correct.
The warranty does not extend to the repair of defects that are
insignificant as far as the product’s operating condition is con-
cerned, such as surface scratches. The warranty does not extend
to the normal adjustments of the product as outlined in the oper-
ating manual, operation training visits, maintenance and clean-
ing measures, or such work which is caused by the neglect of
safety or installation regulations or the settlement of this on the
installation site.
The warranty terms outlined in the joint recommendation of the
Association of Finnish Metal and Engineering Industries and the
Finnish Competition and Consumer Authority are observed to
such an extent which has not been separately mentioned above.
The warranty becomes void, if the product is
 repaired or altered without Gebwell Ltd.’s permission
 used for a purpose, for which it has not been intended

6 Gebwell Gemini Installation, operation, and maintenance manual
 stored in a humid or otherwise unsuitable location
(cf. installation, operating and maintenance manual).
What to do if a malfunction occurs
If a malfunction occurs during the warranty period, the customer
must immediately (normally within 14 days) notify the author-
ised Gebwell reseller from whom the product was bought. The
notification must include which product has malfunctioned
(product model, serial number), the details of the malfunction in
as much detail as possible, as well as the circumstances when the
malfunction has developed and/or occurs. The warranty form,
correctly filled in at the handover time must be submitted on re-
quest. Appealing to a warranty-period notification is not valid
after the warranty period is over, unless the notification has been
submitted in writing during the warranty period.
The notification must be submitted immediately after the mal-
function has been discovered. If the notification is not submitted
immediately once the buyer has noticed the malfunction, or
when the buyer should have noticed the malfunction, the buyer
loses the right to appeal to this warranty.
Maintenance service in Finland
Maintenance work for this product, during the warranty period
and after the warranty period, is performed by the maintenance
organization authorised by the manufacturer, throughout the en-
tire estimated economic life of the heat pump.
How to submit a service request
All warranty repairs, service requests and orders for spare parts
will primarily be submitted directly to the authorised Gebwell
reseller that sold/delivered the product. Before submitting a
service request, the following things must be taken into consid-
eration:
 read the installation, operating and maintenance man-
ual carefully and think whether you have used the de-
vice in accordance with the instructions in the manu-
als
 before submitting a warranty repair request, ensure
that the warranty period is still valid, read the war-
ranty terms carefully and find out the product’s
model and serial numbers
 all parts belonging to a device must be included when
the device is returned
 the returned product must be closed in such a way,
that handling it would not cause health or environ-
mental hazards.
A device changed on the basis of the warranty is the property
of the device manufacturer. Gebwell Ltd. reserves the right to
decide how, where and who will perform the repair work or
change that is at the manufacturer’s responsibility.
Gebwell Ltd. is not liable for the breakdown of a wrongfully in-
stalled device.
The device can only be repaired by a professional. Incorrect re-
pair work and settings can cause danger for the user, the mal-
function of the device, and weaken the efficiency of the device.
The visit of a retailer or a service agent is not free of charge even
during the warranty period, in case the device has to be repaired
due to incorrect installation, repair or adjustment.

v1-6 29082018 7
2 INSTALLATION RECORD
The heating system must be inspected before commissioning following in-force regulations. Only qualified persons may conduct the in-
spection. The below installation record must be filled out before handing the device over to the end user. The completed installation record
is also a condition for the validity of the warranty.
x Description Note: Inspected by: Date:
Collector:
System pressure teste
d
System flushe
d
System vente
d
Brine
Ex
p
ansion vessel
Mud se
p
arato
r
Safet
y
valve
Shut-off valve
Collector loop 1, length
Collector loop 2, length
Collector loo
p
3, len
g
th
Collecto
r
loo
p
4, len
g
th
Collector loo
p
5, len
g
th
Collector loop 6, length
Collector loop 7, length
Collector loop 8, length
x Description Note: Inspected by: Date:
Heatin
g
s
y
stem:
S
y
stem
p
ressure teste
d
S
y
stem flushe
d
System vente
d
Safety valve
Diaphragm expansion vessel
Mud se
p
arato
r
Pressure
g
au
g
e
Shut-off valve
Admission valve
Buffer reservoi
r
x Description Note: Inspected by: Date:
Domestic hot wate
r
:
S
y
stem
p
ressure teste
d
S
y
stem flushe
d
Safet
y
valve
Pressure gauge
Buffer reservoi
r
x Description Note: Inspected by: Date:
Electricit
y
:
Pro
p
ert
y
fuses
Heat
p
um
p
fuses
Phase se
q
uence
32A power socket
Outdoor temperature senso
r

8 Gebwell GEMINI
3 HEAT PUMP OPERATING
INSTRUCTIONS
3.1 General
Gebwell GEMINI is a perfect heat pump, which saves energy
and offers efficient technical possibilities. A well-designed and
appropriately dimensioned ground source heating system is af-
fordable in terms of operating expenses and energy efficient.
With a heat pump, you can efficiently heat both interior air and
domestic hot water. In summer, the system can also be used to
cool interior air in an environmentally friendly fashion.
3.2 Ground source heat energy
A heat pump collects heat from the ground and transfers it inside
the building. The heat can be collected using pipes sunk in a
bored well, heat collection pipes installed near the ground sur-
face or pipes anchored at the bottom of a water system.
Bored well as a heat source
Ground as a heat source
Water system as a heat source
More information on heat collection systems and their scaling
can be found on the website of Gebwell Ltd. and the Finnish
Heat Pump Association.
www.gebwell.com
www.sulpu.fi
3.3 Ground source cooling
The cold temperature of the brine can also be used to cool dwell-
ings. In summer, the free cooling energy can be transferred from
the ground with just a circulation pump. The heat pump system
can be connected to the convection heaters of the ventilation sys-
tem or an underfloor heating/cooling system for cooling pur-
poses.
3.4 Heat pump’s operating principle
The heat pump’s refrigerant circuit includes four main compo-
nents:
 Evaporator
 Compressor
 Condenser
 Expansion valve
The heat in the ground is absorbed into a liquid solution circu-
lating in the heat collection pipes.
In the evaporator, the liquid comes into contact with the refrig-
erant that, when vaporised, binds heat energy from the liquid so-
lution that circulates in the ground. The liquid solution returns to
the ground about 4°C cooler than when coming out to the sur-
face. The lowest permissible temperature for the liquid solution
coming to the heat pump is -5°C.
The compressor increases the pressure and temperature of the
refrigerant. The refrigerant also absorbs the heat energy gener-
ated by the compressor’s operation.

v1-6 29082018 9
The hot refrigerant is conveyed to the condenser, where the heat
energy of the refrigerant is transferred to the water circulating in
the building’s heating system. The refrigerant condenses into liq-
uid upon releasing heat energy.
The pressure of the refrigerant remains high when being trans-
ferred to the expansion valve. In the valve, the refrigerant’s pres-
sure decreases rapidly. From the expansion valve, the refrigerant
passes on to the evaporator where it is once again evaporated. At
this point, the refrigerant absorbs heat from the liquid solution
circulating in the heat collection piping.
3.5 Heating functions
DOMESTIC HOT WATER
The heat pump produces domestic hot water based on the B3
measurement sensor. The domestic hot water’s switching differ-
ential is 5 degrees. The compressor is factory set to activate when
the measurement value drops under +50°C and deactivated when
the value reaches +55°C.
HEATING
The heat pump produces heating water directly into the build-
ing’s heating network in accordance with the set point that is
created from the outdoor temperature and the set heating curve.
The control automation activates the charging on the basis of the
calculated set point and return water measurement (B71) formed
by the controller. The heat pump’s return water switching differ-
ential (2840) setting defines the compressor’s activation and de-
activation points. When the return water measurement value is
less than the set point by half of the return water switching dif-
ferential, the compressor is activated. The compressor turns off
when the return water measurement value reaches the set point
+ half of the return water switching differential. The automation
reduces temperature rise in the return water set point above the
condenser.
Example: Return water switching differential (2840) 6°C. Out-
put water set point: 30°C. Condenser’s temperature difference Δt
6K.
The charging procedure is activated when the return water meas-
urement value (B71) reaches 21°C. The charging ends, when the
return water measurement value is 27°C. The heat pump’s charg-
ing pump rotates whenever it is in heating mode.
MIXING HEATING CIRCUIT:
The heating circuit’s output water set point is calculated in ac-
cordance with the outdoor temperature measurement and the set
heating curve. The controller controls the 3-way mixing valve
and keeps the heating circuit’s output water temperature at the
set point.
HEAT SUPPLY AND SOURCE PUMP:
In order for a heat pump to function at the best possible effi-
ciency, the conditions of the heating system and collector must
be ideal. The difference between the heating system’s output and
input temperatures must be 6°C–10°C and the output and input
temperature difference of the collector must be 3°C–4°C. Effi-
ciency and savings are reduced at temperature differences other
than those described above.
Factory settings:
Charging pump: 7°C
Source pump: 4°C
3.6 Tips for saving
The heat pump's function is to produce heat and domestic hot
water according to your wishes. The system aims to fulfil these
wishes by all means available, within the framework of the set
values.
Important factors affecting the energy consumption are the inte-
rior temperature, hot water consumption, hot water temperature
level, the insulation level of the real estate, as well as the desired
level of comfort.
Please note the above points when making changes on the device
for settings.
IMPORTANT!
Thermostats for floor heating and radiators can have a negative
impact on energy consumption. They slow down the flow in the
heating system and the heat pump will compensate this by rais-
ing the temperature of the network. This will affect the operation
of your device consuming more electricity. Thermostats are de-
signed to react only to control of so-called free-heat (sun, heat
generated by people, fireplaces, etc. ...).

10 Gebwell GEMINI
4 DELIVERY AND
HANDLING
4.1 Delivery contents
 Heat pump
 Outdoor temperature sensor
 Installation, operation and maintenance manual
 Spare seals
 Commissioning and warranty protocoll
 External source pump
4.2 Optional accessories
 External source pump
 Spare valve
 Room sensor (wired)
 Room unit (wired)
 Collector valve group
 Pump heating circuit
 Heating control group
 Cooling control group
 SMS/WEB server, SMARTWEB
 Buffer reservoir for domestic hot water
 Buffer reservoir for heating
 Domestic hot water control group
 Charging package for domestic hot water
 Pool heating set
 Diaphragm expansion vessel for collector
 Diaphragm expansion vessel for heating
 Energy measurement (ONLY AS FACTORY IN-
STALLATION, NO RETROFITS)
 Fixed fuel burner control
 Additional heat source control
 Cooling control
 Modbus communication module
4.3 Storage
Before installation, the heat pump must be kept in its delivery
package in a dry and warm location.
4.4 Transport
The heat pump may be temporarily tilted, but it must not be left
inclined for a long period of time, not even in transit. The heat
pump’s maximum tilt angle is 20°. It is not recommended to
turn the pump on its side. However, if there is a need to turn the
heat pump on its side, for transport purposes, for example, the
compressor unit must be removed for the duration of transit. In
any case the heat pump must not be transported on its back. If
the heat pump has been tilted in transit, you must allow the pump
to stand upright for at least two hours before activation so that
the compressor’s lubrication oil has time to reach the required
locations. Only lift the heat pump by the pallet. The pump must
be transported on the pallet all the way to the installation loca-
tion.
4.5 Removal from package and transport
to final installation location
The product is delivered without the upper device module being
mounted. All products included in the delivery are packed on the
same pallet.
NOTE! THE HEAT PUMP MUST NOT BE TRANSPORTED
IF ONLY THE LOWER COMPRESSOR UNIT IS DE-
TACHED FROM THE FRAME. IF THE HEAT PUMP HAS
NOT BEEN ATTACHED, THE UPPER COMPRESSOR UNIT
MUST ALWAYS BE DETACHED BEFORE DETACHING
THE LOWER COMPRESSOR UNIT.
 Ensure that you have received the correct products
with the correct accessories.
 Remove the packaging material, and inspect the heat
pump for any transport damage. Notify any damage
discovered to the transport company.
 Move the heat pump close to the planned installation
location.
 Lift the heat pump off the pallet.
 Adjust the heat pump so that it is horizontally and
vertically level and stands firmly on the adjustable
legs.
 Ensure that the frame, with the exception of the ad-
justable legs, is not in contact with any building
structures.
 Lift the upper compressor unit in place.
4.6 Safety instructions
The following safety instructions are to be taken into account
when handling, installing and using the equipment.
 Turn off the device’s main switch before any mainte-
nance procedures
 Never compromise safety by bypassing safety de-
vices

v1-6 29082018 11
 Only qualified personnel should conduct maintenance
/ repair measures on the cooling unit of the equip-
ment
 The heat pump is not to be flushed with water
 Keep all the shell plates in place to prevent water
splashing on the electronic components of the equip-
ment.
4.7 Heat pump’s location
A variety of matters related to safety, comfort of use and mainte-
nance must be considered when positioning the heat pump.
The temperature of the location must be between +5°C and
+30°C. The room must be sufficiently ventilated. If the humidity
in the room is high, water condenses on the cold pipe sections of
the collector.
The heat pump compressor generates noise that may be con-
veyed to other spaces via the building’s structures. It is recom-
mended to use flexible parts in the pipe connections. The heat
pump must be positioned in a way that the sound does not disturb
any living areas. If necessary, soundproofing of the wall struc-
tures between the room in which the pump is located and the
living areas can be reinforced and extra rubber pads installed un-
der the pump’s legs. We recommend placing the heat pump in a
separate technical room. The sound transmitted through struc-
tures can be limited with the floor structures of the pump room
and other solutions. A separate cast floor cut off from the build-
ing’s other spaces prevents noise from being carried to living ar-
eas through the floor.
Reserve at least 700 mm of maintenance space in front of the
pump so that the compressor unit can be taken out for mainte-
nance. For the same reason, do not install the pump below the
floor surface.
4.8 Mounting and unmounting the upper
compressor unit
For ease of installation Gebwell Gemini is delivered without the
upper compressor unit being mounted. The upper compressor
unit must be mounted only after the heat pump has been placed
on a solid installation platform and adjusted in a horizontally and
vertically level position.
1. Detach the front panel by opening the screws on top
of the device.
2. Detach the mounting plate of the user terminal dis-
play by opening the screws in the frame support rails.
Place the display on top of the device for the duration
of installation.
NOTE! The display cable can be unconnected from
the back of the user terminal if necessary.
3. Lift the compressor unit up to the mounting level by
means of a vertically adjustable table.
4. Position the unit gently in place by pushing from the
front while pulling it from the lifting loops at the
back.
5. Attach the compressor unit to the frame support rails
using the fixtures included in the delivery.
6. Put the gaskets (in a bag taped to the piping) in place
and tighten the nuts.
7. Connect the mains plugs.
8. Attach the user terminal display to the frame, and
connect the display cable if you unconnected it.
Insulate the connecting points of the collector in or-
der to prevent condensation during use. Insulation is
found in the equipment bag.

12 Gebwell GEMINI
5 HEAT PUMP STRUCTURE
5.1 GEMINI structure
A. Control centre
B. Electrical switches
C. Charge output device 1
D. Charge return device 1
E. Condenser device 1
F. Charging pump Q9.1
G. Conderser drain
H. Charge output device 2
I. Charge return device 2
J. Condenser device 2
K. Charging pump Q9.2
L. Condenser drain
M. Adjustable feet
N. Lifting loops
O. User terminal controller 2
P. Brine out device 1
Q. Brine in device 1
R. Soft-starter / compressor’s motor protection switch
device 1 (F1)
S. User terminal controller 1 (Master device)
T. Compressor1
U. Expansion valve 1
V. Brine out device 2
W. Brine in device 2
X. Soft-starter / compressor’s motor protection switch
device 2 (F2)
Y. Compressor 2
Z. Expansion valve 2

v1-6 29082018 13
5.2 Sensors
Inside the heat pump:
B81 Hot gas sensor
B91 Collector’s inlet sensor
B92 Collector outlet sensor
B21 Heat pump output water sensor
B71 Heat pump return water sensor
External sensors:
B9 Outdoor sensor
B10 Common output water sensor
Reservoir sensors:
B3 Domestic hot water
B4 Additional reservoir 1 (upper)
B41 Additional reservoir 2 (lower)
B42 Additional reservoir 3 (middle)
Heating circuit sensors:
B1 Output water temperature sensor 1
B12 Output water temperature sensor 2
B14 Output water temperature sensor 3
Room sensors:
B5 Room sensor 1
B52 Room sensor 2
B53 Room sensor 3
Other sensors:
B13 Pool sensor
B16 Cooling output water sensor
B22 Fixed fuel burner sensor
B38 Domestic hot water consumption sensor
5.3 Pumps
Inside the heat pump:
Q9 Charging pump
External pumps of the system:
Q8 Source pump (collector)
Heating circuit pumps:
Q2 Heating circuit pump 1
Q6 Heating circuit pump 2
Q20 Heating circuit pump 3
Domestic hot water pumps:
Q4 Domestic hot water circulating pump
Q34 Domestic hot water exchanger’s charging
pump
Other pumps:
Q10 Fixed fuel burner pump
Q19 Pool pump
Q24 Cooling circuit pump
5.4 Control valves
Y1 / Y2 Heating circuit 1 (open / closed)
Y5 / Y6 Heating circuit 2 (open / closed)
Y11 / Y12 Heating circuit 3 (open / closed)
Y23 / Y24 Cooling circuit (open / closed)
Y33 / Y34 Domestic hot water (open / closed)
5.5 Other controls
Q3 Domestic hot water change-over valve
Y21 Cooling change-over valve
Y28 Cooling pump/change-over valve
Y28 Jäähdytyksen pumppu/vaihtoventtiili

14 Gebwell GEMINI
6 DIMENSIONS AND PIPE
CONNECTIONS
6.1 Heat pump connections
6.2 Pipe connections
1 Charge output Ø 35mm
2 Charge return Ø 35mm
3 Brine in Ø 35mm
4 Brine out Ø 35mm

v1-6 29082018 15
7 PIPE INSTALLATION
7.1 Collector
When viewing from the front, the heat pump’s collector pipes
are at the right edge of the device.
NOTE! In GEMINI devices the source pump must be installed
externally. The pump is delivered in conjunction with the equip-
ment delivery. It is recommended that the pump is installed ver-
tically to the line from the ground. In this way, air does not ac-
cumulate inside the pump. External source pump is controlled
by leading heat pump’s controller.
 In the collector/brine, only use connection parts that
are intended for cold conditions.
 Install shut-off valves in the pipe connections as
close as possible to the heat pump.
 A dirt separator (filter) must be installed to the
collector’s line coming from the ground in
accordance with connection diagrams.
 Use supports insulated with rubber to support the
pipes.
 Ensure that water does not spill on the pump or in the
electrical devices during operation.
 The collector must be pressure tested at a pressure of
3bar and the test pressure must be maintained for at
least 30 min.
 Insulate all of the building’s source/brine pipes with
closed-cell insulation in order to prevent water con-
densation.
 Rinse the pipes of any installation debris prior to
installing the heat pump
When measuring the collection circuit, the geographical loca-
tion, soil type, heat pump’s efficiency and the property’s heating
needs must be taken into consideration.
When 40x4.2 PN6.3 PEM hoses are used
Device Recommended
length of collec-
tion piping (m)
Recommended
active drilling
depth (m)
GEMINI 40kW 4x500 – 6x500 4x170 – 5x200
GEMINI 52kW 5x500 – 8x500 5x170 – 7x200
GEMINI 64kW 6x500 – 10x500 6x170 – 9x200
The table values are examples intended to be guidelines. Before
beginning installation, accurate calculations of the building’s
heat requirements must be prepared.
The maximum length for a single collector loop is 500 m. If there
is a need to install more piping, the piping must be divided into
two loops that are connected in parallel. The connection must be
conducted so that the loop flow can be balanced.
The collection piping must rise constantly towards the heat pump
in order to prevent air pockets. If this is not possible, venting
mechanisms must be installed at the high points.
UTILITY
ROOM

16 Gebwell GEMINI
EXAMPLE CONNECTION OF COLLECTION
CIRCUIT, 1-DEVICE CONFIGURATION
The collection circuit must be equipped with module-specific
line flow control valves as shown in the figure. The line flow
control valves must be adjusted device-specifically in order to
ensure optimal operation.
5. Brine in (from the ground)
6. Brine out (into the ground)
EXAMPLE CONNECTION OF COLLECTION
CIRCUIT, 2-DEVICE CONFIGURATION
5. Brine in (from the ground)
6. Brine out (into the ground)
INSTALLATION OF AN EXTERNAL SOURCE
PUMP
The source pump is included in the equipment delivery. Pump
capacity is to be determined for each heating system entity sep-
arately. The electronic controller of the source pump is con-
nected to the leading device, i.e. the master unit. Install the ex-
ternal source pump to the source riser as shown in the figure in
accordance with the installation instructions included in the de-
livery.
7.2 Charging circuit
See the charging circuit’s connection in the connection options
below or the site-specific diagram. Note separate returning water
lines for domestic hot water and heating accumulator when con-
necting charging circuit.
 Charging circuit is connected at the back of the de-
vice.
 Install the required protective devices, mud separator
(strainer) as well as the shut-off and check valves.
 Residual installation impurities must be flushed from
the building’s heating system pipes before installing
the heat pump.
 It is recommended to perform the installation to a
closed heating system with a diaphragm expansion
vessel.
 Ensure that water does not spill on the pump or in the
electrical devices during operation.
 The product must be protected against overpressure
with a safety valve. The safety valve’s maximum
opening pressure must be 2.5 bar, and the valve must
be installed in the heating system’s return pipe. It is
recommended to lead the overflow pipe of the safety
valves to the nearest floor drain. Install the overflow
pipe so that the water can flow out of the pipe with-
out obstructions.
 A connection to a system equipped with thermostats
requires a bypass valve to be installed in all the radia-
tors or that a few thermostats be removed to ensure
sufficient flow. Refer to Technical specifications ta-
ble for pump’s minimum flow
 The heating system must have the device’s minimum
flow, refer to the Technical specifications table for
the minimum flow
Connection of charging circuit, heating/domestic hot water
Note that, when connecting the charging circuit, a dedicated
heating line must be brought from the domestic hot water
heating accumulator to the leading compressor unit control-
ling the heat pump, and a common heating line from the
heating network to both compressor units. A faulty return
water connection mixes the domestic hot water and heating
flows and may cause problems in the operation of the system!
The heat pump must be equipped with a non-return valve, as
shown in the figure, in order to secure proper operation. The
equipment cannot be operated without a non-return valve.
The devices have internal heating line pumps, one for each com-
pressor unit.

v1-6 29082018 17
Install dedicated filters for both compressor units in the heating
circuit as shown in the figure.
1. Charging output, to the domestic hot water heating
accumulator (master unit)
2. Charging return, from the domestic hot water heating
accumulator (master unit)
3. Charging output, to the heating network
4. Charging return, from the heating network
Connection of charging circuit, heating
In the example figure, the heat pump produces heating only for
the building heating system. If connected as shown in figure, the
device does not produce heating for domestic hot water.
3. Charging output, to the heating network
4. Charging return, from the heating network
Connection of charging circuit, 2-device configuration
In the example figure, the upper compressor unit of the leading
device produces heating for domestic hot water, and all four
compressor units together produce heating for the building heat-
ing system.
1. Charging output, to the domestic hot water accumula-
tor (master unit)
2. Charging return, from the domestic hot water accu-
mulator (master unit)
3. Charging output, to the heating network
4. Charging return, from the heating network
CONNECTION TO THE DOMESTIC HOT
WATER AND HEATING ACCUMULA-
TOR
CONNECTION TO THE DOMESTIC HOT
WATER ACCUMULATOR AND DI-
RECTLY TO THE BUILDING HEATING
NETWORK
INSTALLATION OF CHANGE-OVER
VALVE

18 Gebwell GEMINI
Install the change-over valve in accordance with the instructions
included in the product package. Exercise great care when posi-
tioning the actuator to the valve arbour. An incorrectly installed
actuator can cause equipment failure.
A. Charging, domestic hot water (Esbe, square)
B. Charging, heating (Esbe, triangle)
AB. Charging from the heat pump (Esbe, circle)
7.3 Connections of an additional heat
source
Connection of an additional heat source to the heating circuit
The additional heat source can be an oil-fired boiler, natural gas,
district heating or an electric boiler.
The additional heat source affects the pipe connection; the cor-
rectness of the connection should be confirmed with the equip-
ment supplier or representative. The example connection is pre-
sented as a diagram with an oil-fired boiler.
Connecting the additional heat source in series with the heat
pump is recommended. The series connection enables optimal
operation of the heat pump with the additional heat source. In the
series connection, the heat pump acts as the primary heat source,
after which the additional heat source compensates for the heat
deficit of the supply pipe by starting to operate. The additional
heat source requires commissioning the regulator.
The additional heat source control does not include a power
supply for the actuator. The complete additional heat source con-
trol package LVLLO1B includes a power supply for the actua-
tor.
The flow sensor B10 is included in the standard heat pump de-
livery.
If a 3-way mixer valve is used to regulate the additional heat
source, the valve must be dimensioned and selected based on the
heating system.
The actuator and valve are not included in the LVLLO1B pack-
age
7.4 Extraction air heat recovery
The extraction air heat recovery system circulates brine to an ex-
traction air radiator without any need for a collection circuit. Ob-
serve the manufacturer’s instructions when installing the extrac-
tion air radiator. The capacity of the heat pump is to be deter-
mined on the basis of the capacity of the extraction air radiator
and the cooling output capacity of the heat pump.
Example of extraction air heat recovery connection
7.5 Connections for external fixed fuel
burners
Burner control
Burner control refers to any uncontrolled heat source such a
wood burner or a burner equipped with water circulation. The
optional accessory Burner control (KPAKO1A) enables the in-
tegration of a wood burner in the heating system. Heating distri-
bution is to be implemented by means of separate control groups
in order to control output water temperature. In the example con-
nection shown below, the heat pump controller commands the
burner charging pump Q10 in accordance with the programmed
temperature set points on the basis of temperature measurement
output from the accumulator and the wood burner.
7.6 Connecting of domestic hot water sys-
tem
The domestic hot water system must be equipped with a safety
valve (max 10bar) installed in the cold water line as shown in the
figure. It is recommended to lead the overflow pipe of the safety
valves to the nearest floor drain. Install the overflow pipe so that
the water can flow out of the pipe without obstructions.
The domestic hot water safety valve may leak nearly every time
higher consumption of warm domestic hot water ceases. The
overflow is caused by the thermal expansion of cold water and
pressure shocks. The safety valve leak can be prevented by in-
stalling an expansion vessel in domestic hot water network. The
vessel evens out the pressure changes and prevents pressure
shocks.
5. Cold water
6. Domestic hot water
7. Domestic hot water circulation

v1-6 29082018 19
RESERVOIR TANK FOR THE DOMESTIC HOT
WATER SYSTEM
If the consumption of domestic hot water is high, the heat pump
can be supplemented with an electrically heated additional res-
ervoir. The heat pump heats the cold water in the internal reser-
voir, after which the water is led to the external buffer reservoir.
The electric resistance of the external reservoir maintains the
temperature at the desired level. The system uses the external
reservoir to prepare for spikes in the consumption of heat energy.
If there are radiators in the circulation of hot water, the connec-
tion must be confirmed by an HV engineer.

20 Gebwell GEMINI
8 ELECTRICAL CONNEC-
TIONS
8.1 General
Electrical installations and possible services may only be carried
out under the supervision of an authorised electrician. The heat
pump’s power supply is brought through the opening at the back
of the device. The device is connected to a power grid of 400V
(50Hz).
The heat pump’s power supply may not be switched on before
the heat pump’s heating network has been filled with water. This
may cause the electrical heater, overheat protector, pumps or
compressor to get damaged.
 The heat pump must be disconnected before insula-
tion measurement.
 The heat pump wiring diagram can be found in Ap-
pendix Electrical diagram.
 If a circuit breaker is used for the heat pump, it
should be of type C (slow). Check the correct fuse
size on Technical specifications
 Cabling of the heat pump's electrical accessories
should be made through the lead-through of control
centre on the back of the heat pump.
 The heat pump’s internal circulation pumps, automa-
tion and their cabling are protected with automatic
fuses.
8.2 Power supply
The power supply is connected to connectors (2) L1, L2, L3
through the cable opening (1). Pay attention to the correct phase
sequence to ensure correct rotation direction of the compressor.
8.3 Compressor’s motor protection
switches (F1 and F2)
The compressor’s motor protection cuts off the power supply to
the compressor, and acts as the operating switch for the compres-
sor.
Reset: Reset the compressor’s motor protection (F1 upper com-
pressor unit / F2 lower compressor unit) by holding down the
green button (ON position)
Motor protection setting:
Gemini 40: 19A
Gemini 52: 24A
Gemini 64: 28A
8.4 Phase sequence / soft starter
Heat pump’s compressor has a three-phase motor. It is important
that the phase sequence be connected correctly. Pump notifies of
incorrect phase sequence on the controller screen with the text
Soft starter E25 failure. The compressor’s motor protection must
be in ON position, so that the phase notice can be reviewed. If
the motor protection switch is in the OFF position, the controller
will always give a notice: Soft starter E25 failure. The soft starter
notifies all interferences with a red LED light on the front panel
of the soft starter. The amount of LED light flashes indicates the
failure. See soft starter failures in section Failures / soft starter
failures
8.5 Connection of temperature sensors
Outdoor temperature sensors are connected to the heat pump
RVS controller. The sensors are included in the delivery of the
heat pump control centre. For the placement of the sensors, see
the HW diagram included in the delivery and the wiring diagram
on the inside of the control centre lid.
Outdoor sensors are always connected to the master unit. If the
heating system has more than one mixing heating circuits, the
output water flow sensor of Heating circuit 2 must be connected
to device unit 2.
OUTDOOR SENSOR (B9)
The outdoor temperature sensor (B9) is already wired to the con-
trol centre.
Position the sensor in a shaded location on the north or north-
east wall. Do not place the sensor near windows or doors.
Connection: connector k, BX9/M
COMMON FLOW SENSOR B10
The common flow sensor of the heat pump is the control sensor
of the cascade system. Place the sensor in accordance with the
HW diagram included in the delivery. If any external heat
sources controlled by the heat pump are connected to the heating
system, sensor B10 is the control sensor of such external heat
sources.
Connection, connector u, BX2/M
DOMESTIC HOT WATER FLOW SENSOR B3
(ACCUMULATOR)
The domestic hot water flow sensor B3 is the control sensor of
COMMON OUTPUT
WATER WH
BR
WH
BR
WH
BR
VH
BR
WH
BR