EN-8 452161.66.04 · FD 9411
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LI 20TES - LI 28TES
7.3 Heating System Connection
The heating system connections on the heat pump have a 1 ¼"
external thread. 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
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 sys-
tem:
Untreated filling water and make-up water must be of drink-
ing water quality (colourless, clear, free from sediments)
Filling water and make-up water must be pre-filtered (pore
size max. 5 µm).
Scale formation in hot water heating systems cannot be com-
pletely avoided, but in systems with flow temperatures below
60 °C the problem can be disregarded.
With medium and high-temperature heating systems, tempera-
tures above 60°C can be reached.
The following standard values should therefore be adhered to
concerning the filling water and make-up water (according to VDI
2035 Sheet 1):
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 pro-
cedure for setting an overflow valve is described in the chapter
"Start-up". When the minimum heating water flow rate is under-
shot, the plate heat exchanger in the refrigeration circuit 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.
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
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 whenever
the heat pump manager and the heat circulating pump are ready
for operation. If the heat pump is taken out of service or in the
event of a power failure, the system has to be drained. The heat-
ing circuit should be operated with a suitable antifreeze if heat
pump systems are implemented in buildings where a power fail-
ure 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)
Total heat
output in [kW]
Total alkaline earths
in mol/m³ and/or
mmol/l
Total
hardness in °dH
up to 200
2.0
11.2
200 to 600
1.5
8.4
> 600
< 0.02
< 0.11
