Installation manual

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Domestic Hot Water Preparation and Ventilation with Heat Pumps 6.2
Switzerland: Swiss Technical and Scientific
Association for Gas and Water (SVGW) data sheet
TPW: Legionella bacteria in domestic water
installations –
What should be kept in mind?
This data sheet discusses where problems with legionella
bacteria in domestic water could arise and the available options
for effectively reducing the risk of infection.
NOTE
Installation of a flange heater is generally recommended to enable
heating to temperatures of over 60 °C. Electric reheating can be time-
controlled by the controller according to the application and/or customer
requirements.
6.1.12 Connecting more than one domestic hot water cylinder in a single circuit
If water consumption is very high or if heat pumps with an output
of more than approx. 28 kW are implemented for hot water
operation, the heat exchanger area required to ensure that
adequate hot water temperatures are maintained can be created
by connecting the heat exchangers of several domestic hot water
cylinders in parallel or in series. (Refer to German Technical and
Scientific Association for Gas and Water - work sheet W551)
Fig. 6.3: Connecting domestic hot water cylinders in parallel
Connecting more than one domestic hot water in parallel is
particularly suitable where large quantities of water are tapped.
This layout is only possible when identically constructed
domestic hot water cylinders are used. When connecting the
heat exchangers with the hot water circuit, the pipes from the tee
joint onwards leading to each cylinder should have the same pipe
diameter and the same length. This ensures that the hot water
volume flow is divided between the two systems with the same
drop in pressure. (see Fig. 6.3 on p. 157)
Fig. 6.4: Connecting domestic hot water cylinders in series
Connecting domestic hot water cylinders in series is the
preferred installation set-up. It should be taken into consideration
during the integration that the heating water must first pass
through the cylinder from which the domestic water is drawn.
(see Fig. 6.4 on p. 157)
6.2 Domestic Hot Water Heating with Domestic Hot Water Heat Pumps
The domestic hot water heat pump is a ready-to-use heating
device that is exclusively used to heat water for domestic use
and drinking water. Basically, it consists of the casing, the
components for the refrigerant, air and water circuits as well as
all of the control-, regulation and monitoring devices required for
automatic operation. With the help of electrical energy, the
domestic hot water heat pump uses the heat stored in the sucked
in air for domestic hot water heating.
The devices are equipped as standard with an electric heating
element (1.5 kW).
The electric heating element fulfils four functions:
 Supplementary heating: The heating-up period is approx.
halved by switching on the heating element in addition to the
heat pump.
 Antifreeze: The electric heating element switches on
automatically whenever the temperature of the intake air
sinks below 8° C.
 Emergency heating: The domestic hot water supply is
maintained by the heating element when the heat pump is
out of order.
 Higher water temperature: If the required hot water
temperature is higher than the temperature achievable by
the heat pump (approx. 60 °C), it can be raised to a max. of
85 °C (factory setting 65 °C) by means of the heating
element.
NOTE
Whenever the hot water temperatures exceed 60 °C, the heat pump is
switched off and the domestic hot water is heated solely by the heating
element.
The water installations for the heating system are to be carried
out according to DIN 1988.
The condensate hose is attached to the rear of the device. It
should be routed so that the condensate produced can flow away
without obstruction. The condensate should be drained into a U
bend.
The domestic hot water heat pump is wired ready for use: only
the mains plug needs to be plugged into a socket in the building.
NOTE
Connection to a heat pump meter is possible if the domestic hot water
heat pump is installed permanently.
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