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3. Information on the heat pump
The appliance is equipped with sensors that monitor the heating circuit and the refrigerant
circuit.
Other equipment features
Wolf heat pumps require special DHW cylinders for heating the domestic hot water;
these are available from the Wolf range of accessories.
The indirect coil surface area in the DHW cylinders must be at least 0.25 m² per kW
of heating output.
Please note
DHW cylinders
Do not use (for cleaning, polishing, etc.) or store sprays, solvents, chlorinated
cleaning agents, paints, lacquers, adhesives, salts, etc. on or in the vicinity of the
heat pump.
Under unfavourable conditions, these materials may cause corrosion in the heat
pump and other heating system components.
Only clean the casing with a damp cloth and a mild chlorine-free detergent. To finish,
dry off immediately.
Corrosion protection
Water hardness
The adjustable cylinder water temperature can exceed 60 °C. Short-term operation
at temperatures above 60 °C must be monitored in order to prevent scalding. For
permanent operation, appropriate precautions should be taken to prevent draw-off
temperatures above 60 °C, e.g. thermostatic valve.
To protect against scaling, the DHW temperature must be set to max. 50 °C when
the total water hardness is 15 °dH (2.5 mol/m³) or above. If the total hardness is
16.8 °dH or above, we recommend using a water treatment facility in the cold water
supply line when heating DHW, in order to prolong the maintenance interval. Even if
water hardness is less than 16.8 °dH, an increased risk of scaling may occur in some
areas, necessitating suitable softening measures. Failure to take such measures will
result in premature scaling of the appliance and reduced DHW convenience. The
contractor should always check the local conditions.
Water treatment
VDI 2035 Part 1 lists recommendations for the prevention of scaling in heating
systems. Part 2 deals with corrosion on the water side.
When screed drying using the heater rod, particular care should be taken to ensure
that the permissible total hardness is complied with, otherwise there is a risk of
scaling and heater rod failure.
The permissible water hardness is 16.8°dH for system volumes of up to 250 litres
during operation with the electric heating rod.
Please note
In the case of high-volume systems or those where large top-up water volumes
(e.g. due to water losses) are required, the following values should be observed.
If the limit curve is exceeded, an appropriate portion of the system water must be
treated.
Example:
Total hardness of the domestic hot water: 16 °dH
System volume: 500 l
i.e. at least 250 l must be treated.
System volume in l
Permissible hardness in °dH
Water treatment
necessary
No water
treatment
necessary
250 l
Operation without immersion heater
Operation with immersion heater
We also recommend a heating water pH value of between 6.5 and 9.0 for mixed
installations comprising various materials.