42
DHW heating in conjunction with other functions
One-off DHW heating
The "one-off DHW heating" function can be used to
heat the water to the set DHW temperature outside of
the time phases.
Operating instructions for the heat pump
Holiday program
DHW heating is off when a holiday program is active.
Frost protection for the DHW cylinder is active.
Operating instructions for the heat pump
Power-OFF
During a power-OFF period, DHW heating is only pos-
sible via a booster heater, e.g. via the instantaneous
heating water heater or the external heat generator.
The booster heaters must be enabled for DHW heating
so that they can be switched on by the heat pump con-
trol unit (parameters 2340.1, 2544.0, 2796.1).
Note
Operating booster heaters gives rise to additional elec-
tricity or fuel costs.
External blocking
The "external blocking" function can be connected to
digital input 143.2 of the heat pump control unit. No
DHW heating takes place when the contact is active.
Frost protection
■
If the cylinder temperature falls below 5 °C, the DHW
cylinder is heated to 20 °C.
■
Frost protection is always active. The temperature
limits for the frost protection function cannot be
adjusted.
Temperature limits
The range within which the system user can adjust the
set cylinder temperature is delimited by the min. and
max. cylinder temperature (parameters 504.1 and
504.3).
Note
The set temperature for the hygiene function can be
set independently of these limits.
Temperature limits for efficient DHW heating
Parameters 504.5 and 504.6 are used to specify a cyl-
inder temperature range in which DHW heating takes
place in an energy saving manner.
If a set cylinder temperature above this efficient range
is selected, a message is displayed. The system user
is informed that DHW heating is outside the efficient
range of the heat pump.
Further temperature limits
Danger
There is a risk of scalding at DHW temperatures
above 60 °C.
■
Limit the temperature in the DHW flow to
60 °C by means of a mixer assembly, e.g. an
automatic thermostatic mixing valve (DHW cyl-
inder accessory).
■
Switch on scald protection: Via the HMI pro-
gramming unit or parameter 503.0
■
Scald protection:
Scald protection limits the cylinder temperature to
60 °C, even if the set cylinder temperature has been
given a higher value. Scald protection is activated via
parameter 503.0.
■
Hygiene function:
When the hygiene function is activated, the applica-
ble set cylinder temperature is also set. This value
cannot be set higher than the max. cylinder tempera-
ture set in parameter 504.3.
Note
If the max. set cylinder temperature in parameter 504.3
and the set cylinder temperature for the hygiene func-
tion are set higher than 60 °C, scald protection is
switched off when the hygiene function is active.
Systems with a DHW circulation pump
In the factory settings, the DHW circulation pump is
switched off during DHW heating (parameter 497.2).
This reduces the mixing of hot and cold layers in the
DHW cylinder.
Note
The DHW circulation pump will continue to run for the
duration of the set time phase if it had already been
switched on for DHW circulation according to the time
program before DHW heating started.
Function description
DHW heating (cont.)
6218234
Functions
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