Application examples with 2 different heat sources
(auxiliary boiler + RKHBRD unit)
When using 2 heat sources, it is recommended to use a balancing
bottle as follows:
■
Application 5
Space heating with an auxiliary boiler (alternating operation)
Space heating application by either the Rotex indoor unit or by
an auxiliary boiler connected in the system. An auxiliary contact
decides whether either the RKHBRD* indoor unit or the boiler
will operate. This auxiliary contact can e.g. be an outdoor
temperature thermostat, an electricity tariff contact, a manually
operated contact, etc.
Bivalent operation is only possible for space heating operation,
not for the domestic hot water heating operation. Domestic hot
water in such an application is always provided by the domestic
hot water tank which is connected to the Rotex indoor unit.
The auxiliary boiler must be integrated in the piping work and in
the field wiring according to the illustrations below.
■
Be sure that the boiler and the integration of the
boiler in the system is in accordance with
relevant European and national regulations.
■
Rotex can not be put responsible for incorrect or
unsafe situations in the boiler system.
1
2
3
4
3
5 6
9
10
12
12
13
19
11
1
Outdoor unit
2
Indoor unit
3
Electronic expansion
valve
4
Refrigerant heat
exchanger
5
Water heat exchanger
6
Pump
7
Motorised 3-way valve
(optional)
8
Domestic hot water
tank (optional)
9
Compressor
10
Boiler (field supply)
11
Balancing bottle
(field supply)
Installation manual
5
A
B
C1
7
8
M
20
20
13
16
17 18
15
14
12
Shut-off valve
13
Non-return valve
(field supply)
14
Pump (field supply)
15
Collector (field supply)
16
By-pass valve
(field supply)
17
Shut off valve (field
supply)
18
Radiator (field supply)
19
Aquastat valve
(field supply)
20
Shut-off valve
(field supply)
C1
Remote controller
A
Installation place
B
Living room
■ Field wiring
L
th
RKHBRD*/auto / Boiler
C
K1A
K2A
N
Boiler thermostat
Boiler thermostat
C
Auxiliary contact (normal closed)
th
Heating only room thermostat
K1A
Auxiliary relay for activation of RKHBRD* unit
(field supply)
K2A
Auxiliary relay for activation of boiler (field
supply)
■ Operation
When the room thermostat (th) closes, either the RKHBRD*
unit or the boiler starts operating, depending on the position
of the auxiliary contact (C).
■
NOTE
Make sure that auxiliary contact (C) has
sufficient differential or time delay so as to
avoid frequent changeover between the
RKHBRD* unit and the boiler. If the
auxiliary contact (C) is an outdoor
temperature thermostat, make sure to
install the thermostat in the shade, so that
it is not influenced or turned ON/OFF by
the sun.
Frequent switching may cause corrosion
of the boiler in an early stage. Contact the
manufacturer of the boiler.
■
During
heating
RKHBRD* unit, the unit will operate so as
to achieve the target leaving water
temperature as set on the user interface.
When weather dependent operation is
active,
the
determined automatically depending on
the outdoor temperature.
During heating operation of the boiler, the
boiler will operate so as to achieve the
target leaving water temperature as set
on the boiler controller.
Never set the target leaving water
temperature set point on the boiler
controller above 80°C.
Make sure that return water to the RKHBRD* heat
exchanger never exceeds 80°C.
For this reason, never put the target leaving water
temperature set point on the boiler controller
above 80°C and install an aquastat
return water flow of the RKHBRD* unit.
Make sure that the non-return valves (field supply)
are correctly installed in the system.
Make sure that the room thermostat (th) is not
frequently turned ON/OFF.
Rotex shall not be held liable for any damage
resulting from failure to observe this rule.
(a) The aquastat valve must be set for 80°C and must operate to close the
return water flow to the unit when the measured temperature exceeds
80°C. When the temperature drops to a lower level, the aquastat valve
must operate to open the return water flow to the RKHBRD* unit
again.
Indoor unit for air to water heat pump system
RKHBRD*
Boiler
thermostat
A8P
1 2 3 4 5
X Y
K1A
K2A
operation
of
the
water
temperature
is
(a)
valve in the
RKHBRD011~016ABV1+Y1
4PW61218-1C – 2012.06