Heating System Connection - Dimplex LI 9TES Installation And Operating Instructions Manual

7.3 Heating System Connection

The heating system connections on the heat pump have a 1" ex-
ternal 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 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 performance
range (heat pump + boiler combination), flow temperatures 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 hard-
ness values can be found in the table.
Total alkaline
Total heat
earths in mol/m³
output in kW
and/or mmol/l
2,0
< 50
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. 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.
www.dimplex.de
Specific system volume
(VDI 2035) in l/kW
20 < 50 50
< 20
Total hardness in °dH
16,8 11,2
 11,2 8,4
1
< 0,11
8,4
1
< 0,11
1
< 0,11
452161.66.02 · FD 9601
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 14.) 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 oper-
ation. 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 circuit
should be operated with a suitable antifreeze if heat pump sys-
tems are implemented in buildings where a power failure can not
be detected (holiday home).
LI 9TES
EN-9