Technical data

112 | Project planning manual for heat pumps for heating and domestic hot water preparation | 01.2012 www.dimplex.de
8.13 Integration of the heat pump in the heating system
8.13 Constantly regulated tank charging
Two buffer tank thermostats and one contactor (2 contacts) are
necessary for regulation of buffer tanks with large volumes which
are to be charged with a constant temperature.
NOTE
The illustrated circuit ensures full charging of the buffer tank, and in this
way, prevents the heat pump from surging.
Fig. 8.29: Regulation for constantly-regulated tank charging
8.14 Electronically controlled circulating pumps in heating systems
The European Ecodesign Directive calls for electronically con-
trolled circulating pumps to be used from 01.01.2013. With elec-
tronically controlled circulating pumps, the volume flow or speed
of the pump is controlled via the pressure drop in the heating cir-
cuit. If the heat load in a building falls, the thermostat valves
close the heating circuit and the pressure in the system in-
creases. The electronically controlled circulating pump detects
the rise in pressure and reduces the volume flow accordingly.
This means that, eventually, the minimum volume flow can no
longer be guaranteed with the heat pump.
If the unregulated circulating pump is to be replaced with an elec-
tronically regulated circulating pump in an existing heating sys-
tem, the hydraulic integration of the heat pump must be checked
and adapted where necessary. The required minimum volume
flow specified in the heat pump device information must be guar-
anteed even in the worst case scenario. There are three ways to
achieve this:
Install a dual differential pressureless manifold
In this case, the existing overflow valve must be replaced with a
dual differential pressureless manifold (see Chapt. 8.4.3 on
page 100). The dual differential pressureless manifold guaran-
tees the minimum volume flow even when the heating circuits are
closed. The electronically regulated circulating pump is installed
as a circulating pump in the heating circuit in this case. If the ther-
mostats are closed, the electronically regulated circulating pump
reduces the volume flow.
Controlling the circulating pump via WPM
EconPlus
With heat pumps equipped with a WPM EconPlus heat pump
manager, there is the option of controlling the electronically reg-
ulated circulating pump via the heat pump manager with a 0 - 10
Volt signal following a software update. For this, the electroni-
cally regulated circulating pump must have a 0 - 10 Volt input sig-
nal. In this case, no upgrading work is required on the hydraulics.
Hydraulic equalisation with overflow valve
resetting
The electronically regulated circulating pump is set so that it pro-
vides the required minimum heating water flow rate even if the
system counter-pressure increases. The overflow valve setting
must then be checked in accordance with Chapt. 8.3.3 on page
96. If the minimum heating water flow rate is not complied with,
the consumer circuit must be hydraulically disconnected with a
differential pressureless manifold.
NOTE
Electronically regulated circulating pumps should only be combined with
an overflow valve in new installations if the pump can be activated by the
heat pump manager with a 0 - 10 Volt signal.
NOTE
In all three cases, a hydraulic equalisation must be carried out once the
retrofitting work is complete and the controller settings of the heat pump
manager must be checked.
Electrical connection of electronically regulated
circulating pumps
Electronically regulated circulating pumps have high starting cur-
rents, which may shorten the service life of the heat pump man-
ager. A coupling relay must therefore be installed between the
output of the heat pump manager and the electronically regu-
lated circulating pump.
This is not necessary if the maximum permissible operating cur-
rent of the heat pump manager of 2 A and the maximum permis-
sible starting current of the heat pump manager of 12 A are not
exceeded by the electronically regulated circulating pump or a
relevant approval has been issued by the pump manufacturer.
ATTENTION!
It is not permitted to connect more than one electronically regulated
circulating pump via a relay output.
7!
%
1
,'
635
%XIIHUWDQN
/
%
1
$
$
7!