Connection On Heating Side - Dimplex LA 25TU-2 Instructions D'installation Et D'utilisation

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6.2 Connection on heating side

The heating system connections on the heat pump are to be
made inside the device. Refer to the device information for the
connection sizes. Route the connection hoses out of the device
in a downwards direction. An optional pipe kit is available as an
accessory, which can be used to lead the connections out to
the side.
Use a spanner to firmly grip the transitions when connecting
the heat pump.
Before connecting the heating water system to the heat pump,
the heating system must be flushed to remove any impurities,
residue from sealants, etc. Any accumulation of deposits in the
liquefier could cause the heat pump to completely break down.
ATTENTION!
The dirt trap included in the scope of supply is to be installed
in the heat return before the heat pump.
Cleaning and maintenance instructions can be found in the dirt
trap's installation and operating instructions.
Once the heat pump has been connected to the heating sys-
tem, it must be filled, de-aerated and pressure-tested.
Consideration must be given to the following when filling the
system:
 Untreated filling water and make-up water must be of
drinking water quality (colourless, clear, free from sedi-
ments)
 Filling water and make-up water must be pre-filtered (pore
size max. 5µm).
Scale formation in domestic hot water heating systems cannot
be avoided, but in systems with flow temperatures below 60 °C,
the problem can be disregarded. With high-temperature heat
pumps and in particular with bivalent systems in the higher per-
formance range (heat pump + boiler combination), flow tem-
peratures of 60 °C and more can be achieved. The following
standard values should therefore be adhered to with regard to
the filling and make-up water according to VDI 2035, sheet 1:
The total hardness values can be found in the table.
Total alkaline earths
Total heat
in mol/m³ and/or
output in kW
mmol/l
< 50 2,0
2,0
50 - 200
1,5
200 - 600
> 600 < 0,02
1. This value lies outside the permissible value for heat exchangers in heat
pumps.
Fig. 6.1:Guideline values for filling and make-up water in accordance with
VDI 2035
For systems with an above-average specific system volume of
50 l/kW, VDI 2035 recommends using fully demineralized
water and a pH stabiliser to minimize the risk of corrosion in the
heat pump and the heating system.
ATTENTION!
With fully demineralized water, it is important to ensure that
the minimum permissible pH value of 7.5 (minimum
permissible value for copper) is complied with. Failure to
comply with this value can result in the heat pump being
destroyed.
EN-6
Specific system volume
(VDI 2035) in l/kW
20 < 50 50
< 20
Total hardness in °dH
16,8 11,2
 11,2 8,4
< 0,11
8,4
1
< 0,11
1
< 0,11
452163.66.72 · FD 9912
Minimum heating water flow
The minimum heating water flow rate through the heat pump
must be assured in all operating states of the heating system.
This can be accomplished, for example, by installing either a
dual differential pressureless manifold or an overflow valve. The
procedure for setting an overflow valve is described in the
chapter "Start-up". When the minimum heating water flow rate
is undershot, the plate heat exchanger in the refrigeration cir-
cuit can freeze, which can lead to total loss of the heat pump.
The nominal flow rate is specified depending on the max. flow
temperature in the device information and must be taken into ac-
count during planning. With design temperatures below 30 °C in
the flow, the design must be based on the max. volume flow with
5 K spread for A7/W35.
NOTE
The use of an overflow valve is only recommended for panel
heating and a max. heating water flow of 1.3 m³/h. System
faults may result if this is not observed.
Antifreeze
Heat pump systems, which cannot be guaranteed to be frost-
free, should be equipped with a drainage option (see Fig.). The
antifreeze function of the heat pump manager is active when-
ever the manager and the heat circulating pump are ready for
operation. The system has to be drained if the heat pump is
taken out of service or in the event of a power failure. The heat-
ing circuit should be operated with a suitable antifreeze if heat
pump systems are implemented in buildings where a power
failure cannot be detected (holiday home).
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LA 25TU-2 - LA 40TU-2
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