Giacomini GE556-5 Operating instructions

I
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
MODULAR HEAT INTERFACE UNIT
USER AND MAINTENANCE GUIDE
GE5565
EXAMPLES OF POSSIBLE LAYOUTS

II
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
Index
1. General information ...................................................................................................................................................................................................................1
1.1 Warnings .................................................................................................................................................................................................................... 1
1.2 Versions and product codes ..........................................................................................................................................................................2
1.3 Completion codes ..................................................................................................................................................................................................4
1.4 Main features ...........................................................................................................................................................................................................5
1.5 Technical data .........................................................................................................................................................................................................5
1.5.1 Technical data of mandatory components ................................................................................................................. 6
Basic codes GE556Y501, GE556Y502 .........................................................................................................................6
Domestic water circuit: heat exchangers GE556Y511, 512, 513, 514, 516 ......................................... 6
Domestic water circuit: control components GE556Y521, GE556Y522 ................................................7
Primary circuit GE556Y531, GE556Y532 ....................................................................................................................7
Secondary circuit GE556Y541, GE556Y542, GE556Y543, GE556Y546 .................................................... 8
1.5.2 Technical data of optional components ........................................................................................................................9
Insulation GE556Y551 .........................................................................................................................................................9
Additional unit output for domestic cold water GE556Y561 .....................................................................10
Unit output for domestic water recirculation GE556Y562, GE556Y563 .............................................. 11
Thermostatic by-pass GE556Y566 ................................................................................................................................12
System drain cocks GE556Y569 .....................................................................................................................................13
Metal cover GE551Y170 ......................................................................................................................................................14
1.6 Dimensions .............................................................................................................................................................................................................. 15
2. Components ...................................................................................................................................................................................................................................16
3. Operation ..........................................................................................................................................................................................................................................17
4. Hydraulic characteristics ..........................................................................................................................................................................................................19
4.1 Domestic water: domestic hot water production (DHW) .......................................................................................................... 19
4.1.1 Primary circuit for DHW production .................................................................................................................................19
4.1.2 Primary circuit with thermostatic by-pass for DHW production ....................................................................19
4.1.2 Secondary circuit - DHW production .............................................................................................................................. 20
4.2 Heating ....................................................................................................................................................................................................................... 20
4.2.1 High-temperature heating with kit GE556Y542 ....................................................................................................... 20
4.2.2 High-temperature heating with kit GE556Y543 ....................................................................................................... 21
4.2.3 Low-temperature heating with kit GE556Y546 .........................................................................................................21
5. Operational data ...........................................................................................................................................................................................................................22
5.1 Domestic water: domestic hot water production (DHW) ............................................................................................................... 22
5.1.1 DHW production with 16-plate exchanger (GE556Y511, GE556Y512) .......................................................22
5.1.2 DHW production with 26-plate exchanger (GE556Y513, GE556Y514) .......................................................22
5.1.3 DHW production with 36-plate exchanger (GE556Y515, GE556Y516) .......................................................22
5.2 Heating .........................................................................................................................................................................................................................23
5.2.1 High-temperature heating .....................................................................................................................................................23
5.2.2 Low-temperature heating ......................................................................................................................................................23
5.2.3 High + low temperature simultaneous heating .......................................................................................................23
6. Installation ........................................................................................................................................................................................................................................24
6.1 Unpacking .................................................................................................................................................................................................................24
6.2 Preparing the unit for installation ...............................................................................................................................................................24
6.3 Hydraulic system precautions ...................................................................................................................................................................... 24
6.4 Electric system precautions ........................................................................................................................................................................... 24
6.5 Installation ................................................................................................................................................................................................................ 24
6.5.1 Installation of template on wall .......................................................................................................................................... 24
6.5.2 Installation of HIU on template ...........................................................................................................................................25
6.6 Start-up .......................................................................................................................................................................................................................26
6.7 Installation of water and energy meters ................................................................................................................................................27
6.8 HIU electric connections ................................................................................................................................................................................. 27
6.9 Thermostat electric connections ................................................................................................................................................................27
6.9.1 General warnings .........................................................................................................................................................................27
6.9.2 Positioning the thermostat ....................................................................................................................................................27
6.9.3 Connecting the thermostat to the circulator of kit GE556Y546 .....................................................................27
6.9.4 Connecting the thermostat to the thermo-electric actuator of kit GE556Y543 ..................................27

III
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
7. HIU setting ....................................................................................................................................................................................................................................... 28
7.1 Domestic hot water temperature setting (kit GE552Y522) ........................................................................................................28
7.2 Low-temperature heating setting (kit GE552Y546) ........................................................................................................................ 28
7.3 Presetting of dierential pressure control valve R206C (kit GE556Y532) ...........................................................................32
8. Troubleshooting ........................................................................................................................................................................................................................... 35
8.1 Domestic hot water temperature too low ........................................................................................................................................... 35
8.2 Domestic hot water temperature too high ......................................................................................................................................... 35
8.3 Heating circuit water temperature too low .........................................................................................................................................36
8.3.1 GE556-5 with high-temperature kit GE556Y541, GE556Y542, GE556Y543 ..............................................36
8.3.2 GE556-5 with low-temperature kit GE556Y546 ........................................................................................................ 36
8.4 Heating circuit water temperature too high .......................................................................................................................................37
8.4.1 GE556-5 with high temperature kit GE556Y541, GE556Y542, GE556Y543 ..............................................37
8.4.2 GE556-5 with low-temperature kit GE556Y546 ........................................................................................................ 37
8.5 Heating circuit not working ...........................................................................................................................................................................37
8.5.1 GE556-5 with high temperature kit GE556Y541, GE556Y542, GE556Y543 ..............................................37
8.5.2 GE556-5 with low temperature kit GE556Y546 .........................................................................................................37
8.6 Noise in heating system ...................................................................................................................................................................................38
8.7 Problems with thermostatic by-pass (kit GE556Y566) .................................................................................................................. 38
8.8 Problems with domestic water recirculation ......................................................................................................................................38
8.8.1 GE556-5 with recirculation kit GE556Y562 ...................................................................................................................38
8.8.2 GE556-5 with recirculation kit GE556Y563 ...................................................................................................................38
9. Inspections and maintenance ............................................................................................................................................................................................. 39
10. WRAS certications ..................................................................................................................................................................................................................39
11. Spare parts .....................................................................................................................................................................................................................................40
11.1 GE556Y501 ....................................................................................................................................................40
11.2 GE556Y502 ....................................................................................................................................................41
11.3 GE556Y511 ....................................................................................................................................................42
11.4 GE556Y512 ....................................................................................................................................................42
11.5 GE556Y513 ....................................................................................................................................................42
11.6 GE556Y514 ....................................................................................................................................................43
11.7 GE556Y515 ....................................................................................................................................................43
11.8 GE556Y516 ....................................................................................................................................................43
11.9 GE556Y521 ....................................................................................................................................................44
11.10 GE556Y522 ..................................................................................................................................................44
11.11 GE556Y531 ..................................................................................................................................................45
11.12 GE556Y532 ..................................................................................................................................................45
11.13 GE556Y541 ..................................................................................................................................................46
11.14 GE556Y542 ..................................................................................................................................................46
11.15 GE556Y543 ..................................................................................................................................................46
11.16 GE556Y546 ..................................................................................................................................................47
11.17 GE556Y551 ..................................................................................................................................................47
11.18 GE556Y561 ..................................................................................................................................................48
11.19 GE556Y562 ..................................................................................................................................................48
11.20 GE556Y563 ..................................................................................................................................................48
11.21 GE556Y566 ..................................................................................................................................................48
11.22 GE556Y569 ..................................................................................................................................................49
11.23 GE551Y078 ..................................................................................................................................................49
11.24 GE551Y079 ..................................................................................................................................................49
12. Compliance statements ........................................................................................................................................................................................................50

1
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
1. General Information
GE556-5 Heat Interface Units meter thermal energy consumptions for heating and DHW production (Domestic Hot Water) in
modern autonomous systems with centralized heat production (ex. boiler room in large buildings).
HIUs are controlled mechanically through a 3-way priority valve.
When kit GE556Y522 is included, the thermostatic control provides the lowest return temperature during hot water production.
HIUs GE556-5 are modular units where multiple components can be installed to create a HIU based on installation needs
(control of high or low temperature heating with or without balancing valves, control of hot and/or cold domestic water, etc.).
1.1 Warnings
• Installation must be carried out by qualied operators authorized by the building manager.
Refer to specic regulations for use (installation, xing, etc.), operation, recalibration and replacement of meters.
Also refer to the assembly instructions provided with each meter.
• Risk of burns and electric shocks. Only qualied operators authorized by the building manager should access the HIU.
Improper operations may cause serious injuries to people and damage the system.
• An excessively high temperature of the domestic hot water may cause burns, while an excessively low one may lead to undesired
bacterial growth in the water system.
• Do not touch the HIU parts that may become very hot.
• Make sure the HIU has been properly lled with water before connecting it to the power line. Starting the HIU with no water
inside may damage the low-temperature heating unit circulator GE556Y546 (if installed) as well as the HIU itself.
• To prevent burns, during start-up of the HIU make sure no one opens the hot water usage points until the water temperature has
been properly set.
• When starting up the HIU, rst open the primary circuit delivery valves and then the return valves to prevent pollutants from
entering the system. Open the valves slowly to prevent pressure peaks.
• Do not disconnect the electric box from the power line. This may damage the low-temperature unit circulator GE556Y546 (if
installed), the valve actuators, etc.
• Cleaning frequency of the domestic water exchanger depends on the domestic cold water hardness.
• When hardness exceeds 15°f, we recommend using anti-scaling devices which type varies based on the water characteristics.
• If required by regulations in force, install a check valve or backow preventer on the cold water inlet before connecting it to the
template or HIU.
• To improve scaling resistance, we recommend setting domestic water temperature on a value very close to the one of actual use.
• Installation of the thermostat to control a low-temperature zone with kit GE556Y546 requires:
- installation of a low-temperature safety thermostat external to the controlled zone;
- installation of an external zone valve with actuator or thermo-electric actuators on every circuit of the low-temperature manifold,
with control from a thermostat in the low-temperature zone.
• We recommend checking the domestic water exchanger cleanness at the end of the rst year of use; subsequently, the frequency
can be extended to two years according to the actual level of scales.
• The HIU is suitable for installation in boiler rooms and indoors, for use with non-aggressive uids (water, VDI 2035/ÖNORM 5195
glycol-based water).
• When installing the thermostatic by-pass kit, include a safety valve on the HIU domestic hot water outlet.
• Due to vibrations during transport, ALL hydraulic connections must be checked and tightened before installation and
commissioning.
• Before installing the HIU on the template it is necessary to wash all the pipes.
• Any unused connections and ball valves must be closed with a plug.
• The electrical installation must be done by qualied personnel, respecting the current legislation and Standards.

2
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
1.2 Versions and product codes
Starting from basic codes GE556Y501/502, HIUs can be congured by adding various mandatory product codes (total of 5
categories) and possibly a few optionals or completion codes.
MANDATORY CODES OPTIONALS
BASIC
DOMESTIC WATER CIRCUIT
PRIMARY CIRCUIT SECONDARY CIRCUIT Insulation Other optionals
Heat exchangers Control components
GE556Y501
Primary connections
from bottom
GE556Y511
16-plate exchanger
+ 5 mm insulation
GE556Y521
DHW production
without controls
GE556Y531
Primary circuit connections
without controls
GE556Y541
Secondary circuit,
direct heating
without controls
GE556Y551
Insulation
GE556Y561
Unit output for DCW outlet
GE556Y502
Primary connections
from top
GE556Y512
16-plate exchanger
+ 20 mm insulation
GE556Y522
DHW production
with thermostatic control
GE556Y532
Primary circuit connections
with dierential pressure
control valve
GE556Y542
Secondary circuit,
direct heating
with static balancing
GE556Y562
Unit output for domestic
water recirculation
with circulator
GE556Y513
26-plate exchanger
+ 5 mm insulation
GE556Y543
Secondary circuit,
direct heating with
presetting valve and
optional installation
of thermo-electric actuator
GE556Y563
Unit output for domestic
water recirculation
without circulator
GE556Y514
26-plate exchanger
+ 20 mm insulation
GE556Y546
Secondary circuit, low-
temperature heating kit
(circulator + thermostatic
head)
GE556Y566
Thermostatic by-pass to
maintain exchanger DHW
temperature
GE556Y515
36-plate exchanger
+ 5 mm insulation
Kit GE556Y546 can
be ordered
separately or combined to
kits GE556Y541/542/543.
GE556Y569
System
drain cocks
GE556Y516
36-plate exchanger
+ 20 mm insulation
IMPORTANT
The second to last gure of each product code (in red in the table)
indicates the product type:
0for heat interface unit base
1for exchangers of domestic water circuit
2for control components of domestic water circuit
3for control components of primary circuit
4for control components of secondary circuit (heating)
5for insulations (optional)
6for other optional components
To ensure proper operation, at least one product code for each type of
component with 0, 1, 2, 3, 4as second to last gure must be ordered.
Product codes with 5, 6as second to last gure are optional.

3
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
1.3 Completion codes
GE551Y078
Template with 6 shut-o valves,
for GE556Y501 or GE556Y502 HIU
including insulation GE556Y551
GE551Y079
Lowered template with 6 shut-o valves,
for GE556Y501 or GE556Y502 HIU
without insulation
GE500Y254
Additional DCW valve,
for installation on template with
GE556Y561 optional kit
GE500Y255
Pair of additional valves for low temperature
heating delivery and return,
for installation on template with
GE556Y546 kit for secondary circuit
GE551Y170
Metal cover for HIU,
only for HIU with GE551Y078 template
R473 / R473M
Thermo-electric actuator normally closed, to
control the presetting valve
of the with GE556Y543 kit
R473X221: 230 V R473X222: 24 V
R473MX221: 230 V R473MX222: 24 V
GE552
Thermal energy meter
GE552Y159: 3/4”, volumetric,
1,5 m3/h, M-Bus
GE552Y216: 3/4”, volumetric,
1,5 m3/h, M-Bus
with Wireless M-Bus predisposition
GE552Y122 3/4”, ultrasonics,
1,5 m3/h, M-Bus
GE552-2
Domestic water meter
GE552Y190: 3/4”,
domestic cold water, required when
additional unit output
GE556Y561 is installed
GE552Y191: 3/4”,
domestic hot water
• Every HIU includes:
- label with HIU general identication data;
- label guaranteeing compliance with hydraulic tests;
• Each HIU is identied by a series number inside unit and on package.

4
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
Examples of possible congurations
Contact our sales back oce to purchase the product codes required for the desired conguration.
Example 1, purchase code: SM556Y04929
The HIU shown includes the following components:
GE556Y501: primary connections from bottom
GE556Y516: 36-plate exchanger + 20 mm insulation
GE556Y522: domestic hot water production with thermostatic control
GE556Y531: primary circuit connections without controls
GE556Y541: secondary circuit, direct heating without controls
GE551Y079: lowered template with 6 shut-o valves, for HIU GE556Y501 or GE556Y502
Example 2, purchase code: SM556Y05233
The HIU shown includes the following components:
GE556Y501: primary connections from bottom
GE556Y516: 36-plate exchanger + 20 mm insulation
GE556Y522: domestic hot water production with thermostatic control
GE556Y532: primary circuit connections with dierential pressure control valve
GE556Y542: secondary circuit, direct heating with static balancing
GE556Y551: insulation
GE551Y078: template with 6 shut-o valves, for HIU GE556Y501 or GE556Y502 including
insulation GE556Y551
Example 3, purchase code: SM556Y05336
The HIU shown includes the following components:
GE556Y501: primary connections from bottom
GE556Y516: 36-plate exchanger + 20 mm insulation
GE556Y522: domestic hot water production with thermostatic control
GE556Y532: primary circuit connections with dierential pressure control valve
GE556Y543: secondary circuit, direct heating with presetting valve
GE556Y546: secondary circuit, low-temperature heating kit (circul.+ thermost. head)
GE556Y551: insulation
GE556Y561: additional DCW unit output
GE551Y078: template with 6 shut-o valves, for HIU GE556Y501 or GE556Y502 including
insulation GE556Y551
R473MX221: thermo-electric actuator normally closed to control the presetting valve
included with kit GE556Y543
GE500Y254: additional valve for DCW
GE500Y255: pair of additional valves for delivery and heating circuits of low-temperature
heating

5
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
1.4 Main features
• Hydraulic connections: 3/4”M ISO228.
• Insulated heat exchanger for instant production of DHW with 316-stainless steel plates, copper brazing, power up to 50 kW.
• Mechanical priority valve for domestic water production.
• Filter and manual air vent valve on primary circuit.
• WRAS certicated components for domestic water circuit.
• Water hammer arrestor for domestic water circuit (not included if the GE556Y564/565 recirculation kit is present).
• Fit for installation of thermal energy meter and domestic water meters.
Optional features
• Primary circuit top or bottom inlet.
• Polypropylene foam insulation shell.
• Dierential pressure control valve on primary circuit.
• Control of domestic hot water temperature through thermostatic head.
• Control of high-temperature heating circuit ow rate through static balancing valve.
• Additional low-temperature heating circuit with thermostatic head and 15/6 self-modulating circulator,
center distance 130 mm, ErP (2009/125/CE).
• Thermostatic by-pass to maintain temperature of exchanger domestic hot water.
• Recirculation kit with or without circulator for domestic water circuit.
• Varnished metal cover (RAL9010) with key lock, aesthetically appealing.
• Additional unit output for domestic cold water.
• System drain cocks.
1.5 Technical data
• Max. working temperature of primary and secondary circuit (heating and domestic hot water): 90 °C
• Max. working pressure of heating primary and secondary circuit: 10 bar
• Max. dierential pressure of primary circuit: 0,5 bar (if present the GE556Y532 kit: 2 bar)
• Max. working pressure of domestic hot water circuit (DHW): 10 bar
• Temperature range of low-temperature heating secondary circuit with kit GE556Y546: 20÷70 °C (set point 45 °C)
• Temperature range of domestic hot water secondary circuit (DHW) with kit GE556Y522: 20÷70 °C (set point 50 °C)
• Temperature range of thermostatic by-pass with kit GE556Y566: 20÷70 °C
• Nominal ow rate of primary circuit (domestic hot water production):
- With exchanger GE556Y511/512 515 l/h @ 80 °C for 34 kW
- With exchanger GE556Y513/514 620 l/h @ 80 °C for 42 kW
- With exchanger GE556Y515/516 720 l/h @ 80 °C for 50 kW
• Nominal ow rate of high-temperature heating circuit:
- With kit GE556Y541/542 1000 l/h @ ΔT 15 °C (80-65 °C) for 17,5 kW
- With kit GE556Y543 480 l/h @ ΔT 10 °C (80-70 °C) for 5.5 kW
• Nominal ow rate of low-temperature heating circuit:
- With kit GE556Y546 1500 l/h @ ΔT 7 °C (45-38 °C) for 12.5 kW
• Nominal ow rate of high- and low-temperature heating circuit:
- With kit GE556Y542 + GE556Y546 Primary circuit: 770 l/h @ 80-54,5 °C for 23 kW
Low-temperature secondary circuit: 1500 l/h @ ΔT 7 °C (45-38 °C) for 12,5 kW
High-temperature secondary circuit: 600 l/h @ ΔT 15 °C (80-65 °C) for 10 kW
- With kit GE556Y543 +GE556Y546 Primary circuit: 680 l/h @ 80-56 °C for 19 kW
Low-temperature secondary circuit: 1500 l/h @ ΔT 7 °C (45-38 °C) for 12,5 kW
High-temperature secondary circuit: 480 l/h @ ΔT 10 °C (80-70 °C) for 5,5 kW
HIUs are suitable for installation in boiler rooms and indoors, for use with non-aggressive uids (water, VDI 2035/
ÖNORM 5195 glycol-based water).
Electric technical data
• Circulator of low-temperature kit GE556Y546
- Power supply: 230 V / 50 Hz
- Electric power: 3÷45 W
• Circulator of recirculation kit GE556Y562
- Power supply: 230 V / 50 Hz
- Electric power: 3÷4.5 W

6
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
1.5.1 Technical data of mandatory components
Basic codes GE556Y501, GE556Y502
GE556Y501
Primary connections
from bottom
GE556Y502
Primary connections
from top
• Perforatedmetallic frame
• Mechanical priority valve
• Brass spacers for thermal energy and water meters
• Stainless steel pipes
• Filter
• Manual air vent valve
• Water hammer arrestor
• GE556Y501 weight: 9,2 kg
• GE556Y502 weight: 9,7 kg
BASIC
DOMESTIC WATER CIRCUIT PRIMARY
CIRCUIT
SECONDARY
CIRCUIT
OPTIONALS
Heat exchangers Control
components Insulation Other optionals
GE556Y501
Primary
connections from
bottom
GE556Y511
16-plate
exchanger +
5 mm insulation
GE556Y521
DHW production
without controls
GE556Y531
Primary circuit
connections
without controls
GE556Y541
Secondary circuit,
direct heating
without controls
GE556Y551
Insulation
GE556Y561
DCW unit output
GE556Y502
Primary
connections
from top
GE556Y512
16-plate
exchanger +
20 mm insulation
GE556Y522
DHW production
with thermostatic
control
GE556Y532
Primary circuit
connections
with dierential
pressure control
valve
GE556Y542
Secondary circuit,
direct heating with
static balancing
GE556Y562
Unit output for
domestic water
recirculation
including
circulator
GE556Y513
26-plate
exchanger + 5
mm insulation
GE556Y543
Secondary circuit,
direct heating with
presetting valve
GE556Y563
Unit output for
domestic water
recirculation
without circulator
GE556Y514
26-plate
exchanger +
20 mm insulation
GE556Y546
Secondary circuit,
low-temperature
heating kit
(circulator +
thermostatic head)
GE556Y566
Thermostatic
by-pass to
maintain
exchanger DHW
temperature
GE556Y515
36-plate
exchanger +
5 mm insulation
GE556Y569
System
drain cocks
GE556Y516
36-plate
exchanger
+ 20 mm
insulation
BASIC
DOMESTIC WATER CIRCUIT PRIMARY
CIRCUIT
SECONDARY
CIRCUIT
OPTIONALS
Heat exchangers Control
components Insulation Other optionals
GE556Y501
Primary
connections from
bottom
GE556Y511
16-plate
exchanger +
5 mm insulation
GE556Y521
DHW production
without controls
GE556Y531
Primary circuit
connections
without controls
GE556Y541
Secondary circuit,
direct heating
without controls
GE556Y551
Insulation
GE556Y561
DCW unit output
GE556Y502
Primary
connections
from top
GE556Y512
16-plate
exchanger +
20 mm insulation
GE556Y522
DHW production
with thermostatic
control
GE556Y532
Primary circuit
connections
with dierential
pressure control
valve
GE556Y542
Secondary circuit,
direct heating with
static balancing
GE556Y562
Unit output for
domestic water
recirculation
including
circulator
GE556Y513
26-plate
exchanger + 5
mm insulation
GE556Y543
Secondary circuit,
direct heating with
presetting valve
GE556Y563
Unit output for
domestic water
recirculation
without circulator
GE556Y514
26-plate
exchanger +
20 mm insulation
GE556Y546
Secondary circuit,
low-temperature
heating kit
(circulator +
thermostatic head)
GE556Y566
Thermostatic
by-pass to
maintain
exchanger DHW
temperature
GE556Y515
36-plate
exchanger +
5 mm insulation
GE556Y569
System
drain cocks
GE556Y516
36-plate
exchanger
+ 20 mm
insulation
Domestic water circuit: heat exchangers
GE556Y511, GE556Y512, GE556Y513,
GE556Y514, GE556Y515, GE556Y516
GE556Y511
16-plate exchanger
+ 5 mm insulation
GE556Y512
16-plate exchanger
+ 20 mm insulation
Integrated
ow rate regulator
for domestic hot
water production
up to 12 l/min
Weight: 1,4 kg
GE556Y513
26-plate exchanger
+ 5 mm insulation
GE556Y514
26-plate exchanger
+ 20 mm insulation
Integrated
ow rate regulator
for domestic hot
water production
up to 15 l/min
Weight: 1,8 kg
GE556Y515
36-plate exchanger
+ 5 mm insulation
GE556Y516
36-plate exchanger
+ 20 mm insulation
Integrated
ow rate regulator
for domestic hot
water production
up to 18 l/min
Weight: 2,3 kg

7
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
BASIC
DOMESTIC WATER CIRCUIT PRIMARY
CIRCUIT
SECONDARY
CIRCUIT
OPTIONALS
Heat exchangers Control
components Insulation Other optionals
GE556Y501
Primary
connections from
bottom
GE556Y511
16-plate
exchanger +
5 mm insulation
GE556Y521
DHW production
without controls
GE556Y531
Primary circuit
connections
without controls
GE556Y541
Secondary circuit,
direct heating
without controls
GE556Y551
Insulation
GE556Y561
DCW unit output
GE556Y502
Primary
connections
from top
GE556Y512
16-plate
exchanger +
20 mm insulation
GE556Y522
DHW production
with thermostatic
control
GE556Y532
Primary circuit
connections
with dierential
pressure control
valve
GE556Y542
Secondary circuit,
direct heating with
static balancing
GE556Y562
Unit output for
domestic water
recirculation
including
circulator
GE556Y513
26-plate
exchanger + 5
mm insulation
GE556Y543
Secondary circuit,
direct heating with
presetting valve
GE556Y563
Unit output for
domestic water
recirculation
without circulator
GE556Y514
26-plate
exchanger +
20 mm insulation
GE556Y546
Secondary circuit,
low-temperature
heating kit
(circulator +
thermostatic head)
GE556Y566
Thermostatic
by-pass to
maintain
exchanger DHW
temperature
GE556Y515
36-plate
exchanger +
5 mm insulation
GE556Y569
System
drain cocks
GE556Y516
36-plate
exchanger
+ 20 mm
insulation
Domestic water circuit: control components
GE556Y521, GE556Y522
GE556Y522
DHW production
with thermostatic control
Temperature range of
domestic hot
water circuit:
20÷70°C (set point 50 °C)
Weight: 1.3 kg
GE556Y521
DHW production
without controls
Weight: 0.3 kg
Kit GE556Y521 cannot be combined to thermostatic by-pass kit GE556Y566.
BASIC
DOMESTIC WATER CIRCUIT PRIMARY
CIRCUIT
SECONDARY
CIRCUIT
OPTIONALS
Heat exchangers Control
components Insulation Other optionals
GE556Y501
Primary
connections from
bottom
GE556Y511
16-plate
exchanger +
5 mm insulation
GE556Y521
DHW production
without controls
GE556Y531
Primary circuit
connections
without controls
GE556Y541
Secondary circuit,
direct heating
without controls
GE556Y551
Insulation
GE556Y561
DCW unit output
GE556Y502
Primary
connections
from top
GE556Y512
16-plate
exchanger +
20 mm insulation
GE556Y522
DHW production
with thermostatic
control
GE556Y532
Primary circuit
connections
with dierential
pressure control
valve
GE556Y542
Secondary circuit,
direct heating with
static balancing
GE556Y562
Unit output for
domestic water
recirculation
including
circulator
GE556Y513
26-plate
exchanger + 5
mm insulation
GE556Y543
Secondary circuit,
direct heating with
presetting valve
GE556Y563
Unit output for
domestic water
recirculation
without circulator
GE556Y514
26-plate
exchanger +
20 mm insulation
GE556Y546
Secondary circuit,
low-temperature
heating kit
(circulator +
thermostatic head)
GE556Y566
Thermostatic
by-pass to
maintain
exchanger DHW
temperature
GE556Y515
36-plate
exchanger +
5 mm insulation
GE556Y569
System
drain cocks
GE556Y516
36-plate
exchanger
+ 20 mm
insulation
Primary circuit GE556Y531, GE556Y532
GE556Y531
Primary circuit connections
without controls
Use in systems
with max.
primary circuit
di. pressure 0,5 bar
Weight: 0,3 kg
GE556Y532
Primary connections
with dierential pressure control valve
Use in systems with
primary circuit
di. pressure 0,5÷2 bar
or with secondary circuit
di. pressure < bar 0,5 bar
Weight: 1,9 kg
For proper operation of
HIU, the dierential pressure
control valve cannot be set
on values higher than 0,5 bar
(factory setting).
If needed, it can be set
on lower values.

8
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5

RX
0
0
1
2
0
20
40
60
3
4
5
6
7
80
10
20
30
40
50
60
70
80
0,5 1,0 1,5 2,0 3,0 4,03,52,5
0 0,5 1,0 1,5 2,0 3,0 4,03,52,5
Q [m3/h]
Q [m3/h]
P1 [W] H [m]
H [kPa]
III
II
I
RE
max.
max.
III
II
I
Features of GE556Y546 circulator (Δp costant)
BASIC
DOMESTIC WATER CIRCUIT PRIMARY
CIRCUIT
SECONDARY
CIRCUIT
OPTIONALS
Heat exchangers Control
components Insulation Other optionals
GE556Y501
Primary
connections from
bottom
GE556Y511
16-plate
exchanger +
5 mm insulation
GE556Y521
DHW production
without controls
GE556Y531
Primary circuit
connections
without controls
GE556Y541
Secondary circuit,
direct heating
without controls
GE556Y551
Insulation
GE556Y561
DCW unit output
GE556Y502
Primary
connections
from top
GE556Y512
16-plate
exchanger +
20 mm insulation
GE556Y522
DHW production
with thermostatic
control
GE556Y532
Primary circuit
connections
with dierential
pressure control
valve
GE556Y542
Secondary circuit,
direct heating with
static balancing
GE556Y562
Unit output for
domestic water
recirculation
including
circulator
GE556Y513
26-plate
exchanger + 5
mm insulation
GE556Y543
Secondary circuit,
direct heating with
presetting valve
GE556Y563
Unit output for
domestic water
recirculation
without circulator
GE556Y514
26-plate
exchanger +
20 mm insulation
GE556Y546
Secondary circuit,
low-temperature
heating kit
(circulator +
thermostatic head)
GE556Y566
Thermostatic
by-pass to
maintain
exchanger DHW
temperature
GE556Y515
36-plate
exchanger +
5 mm insulation
GE556Y569
System
drain cocks
GE556Y516
36-plate
exchanger
+ 20 mm
insulation
Secondary circuit
GE556Y541, GE556Y542, GE556Y543, GE556Y546
High-temp. kit
GE556Y541
Secondary circuit,
direct heating without
controls
Weight: 0,8 kg
GE556Y542
Secondary circuit, direct
heating with static
balancing
Weight: 1,4 kg
GE556Y543
Secondary circuit,
direct heating with presetting valve
and optional installation of thermo-
electric actuator
Weight: 1,0 kg
Low-temperature kit
GE556Y546
Secondary circuit,
low-temperature heating kit
(Circulator + thermostatic head)
Temperature range of low-
temperature heating circuit:
20÷70°C (set point 45 °C)
Weight: 4,3 kg
KitGE556Y546canbeorderedseparatelyorcombined
to kits GE556Y541, GE556Y542, GE556Y543.

9
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
1.5.2 Technical data of optional components
Insulation GE556Y551
GE556Y551
Insulation
Polypropylene foam insulation (EPP 40 g/l) including factory-
tted back shell and removable clip-on front shell.
Also included are two removable doors to read thermal
energy meter display and to install low-temperature kit with
circulator.
Weight: 1,0 kg
BASIC
DOMESTIC WATER CIRCUIT PRIMARY
CIRCUIT
SECONDARY
CIRCUIT
OPTIONALS
Heat exchangers Control
components Insulation Other optionals
GE556Y501
Primary
connections from
bottom
GE556Y511
16-plate
exchanger +
5 mm insulation
GE556Y521
DHW production
without controls
GE556Y531
Primary circuit
connections
without controls
GE556Y541
Secondary circuit,
direct heating
without controls
GE556Y551
Insulation
GE556Y561
DCW unit output
GE556Y502
Primary
connections
from top
GE556Y512
16-plate
exchanger +
20 mm insulation
GE556Y522
DHW production
with thermostatic
control
GE556Y532
Primary circuit
connections
with dierential
pressure control
valve
GE556Y542
Secondary circuit,
direct heating with
static balancing
GE556Y562
Unit output for
domestic water
recirculation
including
circulator
GE556Y513
26-plate
exchanger + 5
mm insulation
GE556Y543
Secondary circuit,
direct heating with
presetting valve
GE556Y563
Unit output for
domestic water
recirculation
without circulator
GE556Y514
26-plate
exchanger +
20 mm insulation
GE556Y546
Secondary circuit,
low-temperature
heating kit
(circulator +
thermostatic head)
GE556Y566
Thermostatic
by-pass to
maintain
exchanger DHW
temperature
GE556Y515
36-plate
exchanger +
5 mm insulation
GE556Y569
System
drain cocks
GE556Y516
36-plate
exchanger
+ 20 mm
insulation
Ref. Description
ARemovable front door for installation of low-temperature kit GE556Y546
BRemovable front door for installation of energy meter with splittable display
CCut-out prole for installation of energy meter with non-splittable display
DCut-out prole for installation of recirculation kit GE556Y562/GE556Y563
ECut-out prole for installation of system drain cocks GE556Y569
601
631
195
FRONT SHELL: INTERNALFRONT SHELL: EXTERNAL REAR SHELL + FRONT: BOTTOM VIEW
A
BC
D E
Dimensions in mm
The insulation is installed at factory and must be purchase with the HIU.
It cannot be installed at a later time.
Use template GE551Y078 when insulation is included.

10
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
Additional unit output for domestic cold water
GE556Y561
GE556Y561
DCW unit output
Additional unit output for domestic cold water including
removable brass spacer for installation of domestic cold
water meter (110 mm center distance).
Additional unit output GE556Y561 must be installed by
screwing the special nut on the Tee tting of the domestic
water circuit (Ref. 1).
We recommend installing additional valve GE500Y254 (Ref. 2)
when additional output GE556Y561 is included.
Weight: 0,4 kg
BASIC
DOMESTIC WATER CIRCUIT PRIMARY
CIRCUIT
SECONDARY
CIRCUIT
OPTIONALS
Heat exchangers Control
components Insulation Other optionals
GE556Y501
Primary
connections from
bottom
GE556Y511
16-plate
exchanger +
5 mm insulation
GE556Y521
DHW production
without controls
GE556Y531
Primary circuit
connections
without controls
GE556Y541
Secondary circuit,
direct heating
without controls
GE556Y551
Insulation
GE556Y561
DCW unit output
GE556Y502
Primary
connections
from top
GE556Y512
16-plate
exchanger +
20 mm insulation
GE556Y522
DHW production
with thermostatic
control
GE556Y532
Primary circuit
connections
with dierential
pressure control
valve
GE556Y542
Secondary circuit,
direct heating with
static balancing
GE556Y562
Unit output for
domestic water
recirculation
including
circulator
GE556Y513
26-plate
exchanger + 5
mm insulation
GE556Y543
Secondary circuit,
direct heating with
presetting valve
GE556Y563
Unit output for
domestic water
recirculation
without circulator
GE556Y514
26-plate
exchanger +
20 mm insulation
GE556Y546
Secondary circuit,
low-temperature
heating kit
(circulator +
thermostatic head)
GE556Y566
Thermostatic
by-pass to
maintain
exchanger DHW
temperature
GE556Y515
36-plate
exchanger +
5 mm insulation
GE556Y569
System
drain cocks
GE556Y516
36-plate
exchanger
+ 20 mm
insulation
1
2
Kv of domestic cold water circuit
BA
10000
1000
P [mm H2o]
Q [l/h]
100
10
10 100 100001000
Kv = 6,6

11
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
When the GE556Y562/GE552Y563 domestic water recirculation kit is
included, the GE556Y566 thermostatic by-pass kit must be installed as well.
When the GE556Y564/GE552Y565 domestic water recirculation kit is
included, the GE500Y259 water hammer arrestor kit cannot be present.
When the GE556Y562/GE552Y563 domestic water recirculation kit is
included, it is necessary to provide a safety valve or an expansion vessel
on the domestic water recirculation circuit.
BASIC
DOMESTIC WATER CIRCUIT PRIMARY
CIRCUIT
SECONDARY
CIRCUIT
OPTIONALS
Heat exchangers Control
components Insulation Other optionals
GE556Y501
Primary
connections from
bottom
GE556Y511
16-plate
exchanger +
5 mm insulation
GE556Y521
DHW production
without controls
GE556Y531
Primary circuit
connections
without controls
GE556Y541
Secondary circuit,
direct heating
without controls
GE556Y551
Insulation
GE556Y561
DCW unit output
GE556Y502
Primary
connections
from top
GE556Y512
16-plate
exchanger +
20 mm insulation
GE556Y522
DHW production
with thermostatic
control
GE556Y532
Primary circuit
connections
with dierential
pressure control
valve
GE556Y542
Secondary circuit,
direct heating with
static balancing
GE556Y562
Unit output for
domestic water
recirculation
including
circulator
GE556Y513
26-plate
exchanger + 5
mm insulation
GE556Y543
Secondary circuit,
direct heating with
presetting valve
GE556Y563
Unit output for
domestic water
recirculation
without circulator
GE556Y514
26-plate
exchanger +
20 mm insulation
GE556Y546
Secondary circuit,
low-temperature
heating kit
(circulator +
thermostatic head)
GE556Y566
Thermostatic
by-pass to
maintain
exchanger DHW
temperature
GE556Y515
36-plate
exchanger +
5 mm insulation
GE556Y569
System
drain cocks
GE556Y516
36-plate
exchanger
+ 20 mm
insulation
Unit output for domestic water recirculation
GE556Y562 (w/ circulator), GE556Y563 (w/o circulator)
GE556Y562
Unit output for domestic
water recirculation
including circulator
GE556Y563
Unit output for domestic
water recirculation
without circulator
The recirculation unit output maintains the temperature
of domestic hot water inside the domestic water circuit,
channeling it back into the heat exchanger to make
domestic water instantly available. To install the unit output
for domestic water recirculation, follow the steps below:
-onthe upperpart, screw therecirculationkit nutontheTee tting
(Ref. 1) on the cold water delivery circuit of the heat exchanger;
- on the lower part, screw the metal bracket of the
recirculation kit (Ref. 2) on the HIU template (Note: the metal
bracket is not included with kit GE556Y563).
GE556Y562 weight: 1,4 kg; GE556Y563 weight: 0,3 kg
Characteristics of recirculation kit circulator GE556Y562
• Max. working temperature: 65 °C (75 °C for max. 2h)
• Max. working pressure: 10 bar
• Power supply: 230 V
• Electric absorption: 3÷4,5 W
• Protection class: IP42
• Max. water hardness: 15 °f
0
0,2
0,4
0,6
0,8
1,0
0 0,1 0,2 0,3 0,4 0,5
Q [m3/h]
H [m]
1
2
For proper metering when installing the domestic hot
water recirculation kit, also install the additional
domestic cold water unit output (GE556Y561) and reverse
the inlet/outlet ows of domestic cold water (A and B).
Place the label of reference over the template label, in the
position of the domestic cold water connections .
L
BDICAG HEF
GE556Y561

12
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
BASIC
DOMESTIC WATER CIRCUIT PRIMARY
CIRCUIT
SECONDARY
CIRCUIT
OPTIONALS
Heat exchangers Control
components Insulation Other optionals
GE556Y501
Primary
connections from
bottom
GE556Y511
16-plate
exchanger +
5 mm insulation
GE556Y521
DHW production
without controls
GE556Y531
Primary circuit
connections
without controls
GE556Y541
Secondary circuit,
direct heating
without controls
GE556Y551
Insulation
GE556Y561
DCW unit output
GE556Y502
Primary
connections
from top
GE556Y512
16-plate
exchanger +
20 mm insulation
GE556Y522
DHW production
with thermostatic
control
GE556Y532
Primary circuit
connections
with dierential
pressure control
valve
GE556Y542
Secondary circuit,
direct heating with
static balancing
GE556Y562
Unit output for
domestic water
recirculation
including
circulator
GE556Y513
26-plate
exchanger + 5
mm insulation
GE556Y543
Secondary circuit,
direct heating with
presetting valve
GE556Y563
Unit output for
domestic water
recirculation
without circulator
GE556Y514
26-plate
exchanger +
20 mm insulation
GE556Y546
Secondary circuit,
low-temperature
heating kit
(circulator +
thermostatic head)
GE556Y566
Thermostatic
by-pass to
maintain
exchanger DHW
temperature
GE556Y515
36-plate
exchanger +
5 mm insulation
GE556Y569
System
drain cocks
GE556Y516
36-plate
exchanger
+ 20 mm
insulation
Thermostatic by-pass GE556Y566
GE556Y566
Thermostatic by-pass to
maintain exchanger DHW
temperature
The thermostatic by-pass kit maintains the exchanger
temperature for production of domestic hot water. Fit the
thermostatic by-pass kit on the HIU screwing the special nuts
on the HIU Tee ttings (Ref. 1 and 2) to ensure hydraulic seal.
Weight: 0,5 kg
1
2
Kv of domestic water primary circuit with by-pass kit and temperature setting through thermostatic head
Setting range of thermostatic heads: 20÷70 °C
DE
10000
1000
P [mm H2o]
Q [l/h]
100
10
10 100 100001000
Kv = 0,62
Thermostatic by-pass kit GE556Y566 must be installed with domestic water recirculation kit GE556Y562/GE556Y563.
Thermostatic by-pass kit GE556Y566 cannot be combined to kit GE556Y521.

13
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
System drain cocks GE556Y569
GE556Y569
System drain
cocks
The system drain cocks can be installed on the ttings of
the primary outlet (Ref. 1) and high-temperature heating
delivery circuits (Ref. 2). Installation varies based on type of
system (primary connections from top or bottom), as shown
in pictures below.
To install the drain cocks, loosen the HIU tting caps and
screw on the self-sealing cocks using a 12 mm Allen wrench.
Weight: 0,5 kg
1 2
2
1
BASIC
DOMESTIC WATER CIRCUIT PRIMARY
CIRCUIT
SECONDARY
CIRCUIT
OPTIONALS
Heat exchangers Control
components Insulation Other optionals
GE556Y501
Primary
connections from
bottom
GE556Y511
16-plate
exchanger +
5 mm insulation
GE556Y521
DHW production
without controls
GE556Y531
Primary circuit
connections
without controls
GE556Y541
Secondary circuit,
direct heating
without controls
GE556Y551
Insulation
GE556Y561
DCW unit output
GE556Y502
Primary
connections
from top
GE556Y512
16-plate
exchanger +
20 mm insulation
GE556Y522
DHW production
with thermostatic
control
GE556Y532
Primary circuit
connections
with dierential
pressure control
valve
GE556Y542
Secondary circuit,
direct heating with
static balancing
GE556Y562
Unit output for
domestic water
recirculation
including
circulator
GE556Y513
26-plate
exchanger + 5
mm insulation
GE556Y543
Secondary circuit,
direct heating with
presetting valve
GE556Y563
Unit output for
domestic water
recirculation
without circulator
GE556Y514
26-plate
exchanger +
20 mm insulation
GE556Y546
Secondary circuit,
low-temperature
heating kit
(circulator +
thermostatic head)
GE556Y566
Thermostatic
by-pass to
maintain
exchanger DHW
temperature
GE556Y515
36-plate
exchanger +
5 mm insulation
GE556Y569
System
drain cocks
GE556Y516
36-plate
exchanger
+ 20 mm
insulation

14
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
GE551Y078
Template with 6 shut-o valves,
for GE556Y501 or GE556Y502 HIU
including insulation GE556Y551
GE551Y079
Lowered template with 6 shut-o valves,
for GE556Y501 or GE556Y502 HIU
without insulation
GE500Y254
Additional DCW valve,
for installation on template with
GE556Y561 optional kit
GE500Y255
Pair of additional valves for low temperature
heating delivery and return,
for installation on template with
GE556Y546 kit for secondary circuit
GE551Y170
Metal cover for HIU,
only for HIU with GE551Y078 template
R473 / R473M
Thermo-electric actuator normally closed, to
control the presetting valve
of the with GE556Y543 kit
R473X221: 230 V R473X222: 24 V
R473MX221: 230 V R473MX222: 24 V
GE552
Thermal energy meter
GE552Y159: 3/4”, volumetric,
1,5 m3/h, M-Bus
GE552Y216: 3/4”, volumetric,
1,5 m3/h, M-Bus, with Wireless M-Bus
predisposition
GE552Y122 3/4”, ultrasonic,
1,5 m3/h, M-Bus
GE552-2
Domestic water meter
GE552Y190: 3/4”, domestic cold water
domestic cold water,
required when additional unit output
GE556Y561 is installed
GE552Y191: 3/4”, domestic hot water,
Metal cover GE551Y170
GE551Y170
HIU locking metal cover
The metal cover kit can be installed only on HIUs complete
of insulation and template GE551Y078.
The kit includes a RAL 9010 varnished metal cover (Ref. 1),
an upper bracket to snap on the cover (Ref. 2) and a lower
bracket to lock the HIU (Ref. 3).
To install cover kit GE551Y170, follow the steps below:
- t the upper bracket to the wall (Ref. 2) placing it on the
insulation and making sure the holes (Ref. A) are facing up (use
screw anchors t for the type of wall and equipment weight).
- t the lower bracket (Ref. 3) on the template using Ø 4 mm
rivets and making sure the fold is facing up.
- snap the metal cover (Ref. 1) on the upper bracket (Ref. 2),
inserting the special metal teeth (Ref. B) in the upper bracket
holes (Ref. A) .
Now the HIU can be closed using the special lock on the
lower part of the metal cover (Ref. C).
To access the HIU for inspection and/or maintenance,
remove the metal cover completely tilting it slightly and
pulling it out from the upper bracket.
Weight: 6,0 kg
2
1
A
A
B
B
C
A
A
B
B
The metal cover can be installed only when
template GE551Y078 is included. It cannot be
installed on lowered template GE551Y079.

15
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
1.6 Dimensions
585
801
717
560 146
60 60 60 60 60 60 60 60
L
ADICBGHEF
40
HIU GE556Y501 accessories included
+ template GE551Y079
585
801
790
560
146
26
60 60 180 60 60 60
L
AICBGHF
DE
60
40
HIU GE556Y502 accessories included
+ template GE551Y079
724
871
779
609 200
Cover GE551Y170 + template GE551Y078
631
829
738
601 195
Insulation GE556Y551 + template GE551Y078
Legend
A: Domestic cold water outlet
B: Domestic cold water inlet
C: Domestic hot water outlet
D: Primary inlet
E: Primary outlet
F: High-temperature heating delivery
G: Low-temperature heating delivery
H: Low-temperature heating return
I: High-temperature heating return
L: Domestic hot water recirculation
Dimensions in mm

16
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
2. Components
8
15
12
27
28
19
24
23
4
2
22
21
3
20
7
9
1
14
10
13
25
16b
26
17
8
BCAFGDIE HFGIH
DE
27
28
19
24
23
4
2
22
21
3
20
7
29
5
6
18
11
15
12
9
1
14
10
13
25
16a
26
17
29
5
6
18
11
BCA
L
Legend
1Filter
PRIMARY CIRCUIT
2Probe housing for thermal energy meter
3Probe housing for dierential pressure control valve
4Mechanical priority valve
5Manual air vent valve
6Brass spacer for thermal energy meter
7Dierential pressure control valve
8System drain cock or connection to ll unit or connection for pressure probes (OPTIONAL)
9Thermostatic by-pass kit (OPTIONAL)
DOMESTIC WATER
PRIMARY AND SECONDARY CIRCUIT
10 Thermostatic head for temperature control of domestic water circuit
11 Heat exchanger
12 Brass spacer for domestic cold water meter (DCW)
13 System drain cock or connection to ll unit or connection for pressure probes (OPTIONAL)
14 Flow rate regulator
15 Brass spacer for domestic hot water meter (DHW)
16a Water hammer arrestor
16b Domestic water recirculation kit with circulator (kit GE556Y562) or without circulator (kit GE556Y563).(OPTIONALS)
17 Check valve
18 Check valve
19 Static balancing valve (kit GE556Y542) or presetting valve (kit GE556Y543)
HIGH
TEMP.
HEATING SECONDARY
CIRCUIT
20 System drain cock or connection to ll unit or connection for pressure probes (OPTIONAL)
21 Check valve
LOW
TEMPERATURE
22 Circulator
23 Regulation lockshield
24 Thermostatic head for heating temperature control
25 Metal template
OTHER
COMPONENTS
26 Shut-o valves for HIU installation
27 Cabinet with electric connection terminals
28 Metal frame
29 Insulation (OPTIONAL)
A: Domestic cold water outlet
B: Domestic cold water inlet
C: Domestic hot water outlet
D: Primary inlet
E: Primary outlet
F: High-temperature heating delivery
G: Low-temperature heating delivery
H: Low-temperature heating return
I: High-temperature heating return
L: Domestic hot water recirculation

17
0858EN July 2020
U SER AND MAINTENANCE GUIDE
MODULAR HEAT INTERFACE UNIT
GE556-5
3. Operation
C H
E
BDICAGHEF
C H
E
LDICGHEF
R
BA
When recirculation kit
(GE556Y562/563) is included,
install the additional unit
output for domestic cold water
(GE556Y561) and reverse the
domestic cold water inlet/outlet
ows (A and B) as shown in the
diagram on the side.
Legend
Filter Mechanical priority valve
Probe housing for thermal energy meter Check valve
CBrass spacer for domestic cold water meter HBrass spacer for domestic hot water meter
Heat exchanger Manual air vent valve
E
Brass spacer for thermal energy meter Dierential pressure control valve
Regulation lockshield Static balancing valve (kit GE556Y542) *
* or presetting valve (kit GE556Y543)
Thermostatic head with temperature probe Circulator
Probe housing for dierential pressure control valve Water hammer arrestor
RCirculator for DHW recirculation kit
A: Domestic cold water outlet
B: Domestic cold water inlet
C: Domestic hot water outlet
D: Primary inlet
E: Primary outlet
F: High-temperature heating delivery
G: Low-temperature heating delivery
H: Low-temperature heating return
I: High-temperature heating return
L: Domestic hot water recirculation