85
7
A
7.18 Retrieval function
This function is used to retrieve energy from the calorifier
and load it in the DHW tank.
If the temperature at tank sensor top (TSO) is lower by 3K
than the tank setpoint value and the calorifier temperature
top (TPO) is higher than TSO, the PPS pump is switched
on.
The retrieval is stopped, if the
Tank Temp. Setpoint
at
sensor TSO is exceeded, or if the temperature at sensor
TPO is less than “Tank load. diff Off” above TSO.
Variation: 5, 7, 10, 25, 36, 50, 51, 53, 60…64, 84
A
7.20 Heating return temperature increase
If the calorifier temperature top (TPO) is higher than the
heating return temperature increase (THR) by R
eturn
Diff. On
, the output heating return temperature increase
switches on.
If the temperature differential between TPO and THR is
lower than
Return Diff. Off
, the output heating return
temperature increase switches off.
Variation: 9…11, 15, 16, 19, 27, 31, 34, 38, 42, 45, 49,
56, 59, 62, 65
A
7.21 Collector cascade
The collector cascade is treated the same way as two
independent differential controls.
Basically, collector cascade should always be treated like
two individual differential controls on the same user
(tank, calorifier, swimming pool).
Variation: 22…34, 50, 74
A
7.17 DHW via plate heat exchanger
The primary pump PWW is switched on if the
cold water temperature at the plate heat exchanger TKW
falls below 30°C or the sensor input has short circuited
and the DHW temperature at the plate heat exchanger
TWW is lower than the tank setpoint temperature set.
The pump is switched off if the DHW temperature at the
plate heat exchanger TWW is higher than the tank
setpoint temperature set or the cold water temperature at
the plate heat exchanger TKW increases to above 30°C,
or the short circuit at the sensor input is rectified.
The speed control of the PWW pump is used to try to
control the DHW setpoint value (Tank setpoint
temperature) at sensor TWW.
If the calorifier temperature at sensor top (TPO) is lower
than the DHW setpoint tempe10K, the setpoint for
the speed control is formed based on the temperature
TPO. The setpoint value then is TPO –10K.
Variation: 14, 16
A
7.19 Bi-directional loading between several tanks
This function is used to transfer energy from the calorifier
to the additional calorifier and visa-versa.
If the calorifier temperature top (TPO) is higher than the
“Setpoint Temp. Load transfer” and by at least 5K higher
than the additional calorifier temperature bottom (TZU),
the PPZ pump is switched on. Loading of the additional
calorifier is stopped, when “Setpoint Temp. Load transfer”
at TPO drops by 2K or when the temperature on TPO is
less than 3K above TZU. For retrieval loading from the
additional calorifier to the calorifier pump PZP is switched
on, when the temperature on TPO is less than “Calorifier
Temp. Setpoint” by 2K and the temperature on the
additional calorifier top (TZO) is at least 5K above the
temperature on TPO.
Retrieval loading is stopped when the “Calorifier Temp.
Setpoint” at sensor TPO is exceeded or when the
temperature at sensor TZO is less than 3K above TPO.
Variation: 72…80
A
7.16 Load function DHW tank via plate heat exchanger
If the collector temperature (TKO) increases by the
...Diff. On
via the tank setpoint temperature,
solar loading is initiated. The PWT pump runs at the lowest
speed (30%), until the tank setpoint temperature is
reached at the sensor TWT. The controller now tries to
maintain the tank setpoint temperature at TWT. During
calorifier loading the speed control attempts to achieve a
temperature higher thant sensor TPU by “Calorifier control
diff” at sensor TWT.
Once the tank setpoint temperature(TSU) has been
reached, loading continues until
...Temp. Maximum
has
been achieved.
If the temperature differential between TKO and TSU is
less than
...Diff. On
the pump switches off.
Variation: 3, 8, 11, 63…65, 80, 84
