Heating System Connection; Temperature Sensor - Dimplex LI 9TU Instructions D'installation Et D'utilisation

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7.3 Heating System Connection

The heating system connections on the heat pump have a 1¼"
external thread. Use a spanner to firmly grip the transitions
when connecting the heat pump.
The connection on the heating side can also be made towards
the right. To do this, the left and right bottom front panels must
be removed. The two connecting pipes, including pipe sup-
ports, must be moved from the left to the right side of the de-
vice. The front panels must then be re-mounted the opposite
way around.
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
liquifier could cause the heat pump to completely break down.
For systems in which the heating water flow can be shut off via
the radiator or thermostat valves, an overflow valve must be in-
stalled in a heating bypass behind the heat pump by the cus-
tomer. This ensures a minimum heating water flow rate through
the heat pump and helps to avoid faults.
Once the heating system has been installed, 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. 5 µm).
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
2.0
< 50
2.0
50 - 200
200 - 600 1.5
> 600 < 0.02
1. This value lies outside the permissible value for heat exchangers in heat
pumps.
Fig. 7.1: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-8
Specific system volume
(VDI 2035) in l/kW
< 20 20 < 50 50
Total hardness in °dH
16.8 11.2
 11.2 8.4
1
< 0.11
8.4
1
< 0.11
1
< 0.11
452160.66.74 · FD 9912
Minimum heating water flow rate
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
account 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.
The specified nominal flow rate (See "Device Information" on
page 13.) must be guaranteed in every operating status. An in-
stalled flow rate switch is used only for switching off the heat
pump in the event of an unusual and abrupt drop in the heating
water flow rate and not to monitor and safeguard the nominal
flow rate.
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
A method of manual drainage (see illustration) should be pro-
vided for heat pumps which are exposed to frost. The antifreeze
function of the heat pump manager is active whenever the heat
pump manager and the heat circulating pump are ready for op-
eration. If the heat pump is taken out of service or in the event
of a power failure, the system has to be drained. The heating cir-
cuit should be operated with a suitable antifreeze if heat pump
systems are implemented in buildings where a power failure
can not be detected (holiday home).

7.4 Temperature sensor

The following temperature sensors are already installed or must
be installed additionally:
External temperature sensor (R1) supplied (NTC-2)

Return temperature sensor (R2) installed (NTC-10)

Flow temperature sensor (R9) installed (NTC-10)

LI 9TU - LI 12TU
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