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9.5
9.4.3
Variably-Regulated (Sliding) Boiler (Burner Regulation)
In contrast to constantly-regulated boilers, variably-regulated
boilers supply hot water at a temperature that is directly based on
the respective external temperature. The three-way reversing
valve has no regulatory function i.e. it should only direct the hot
water flow past or through the boiler, depending on the operating
mode.
In the case of heat pump only operation, the heating water is
directed past the boiler to avoid losses caused by heat
9.4.4
Special Program for Older Boilers and Main Cylinder Systems
If the 2nd heat generator has been requested and the so-called
special program is activated in the menu "Settings - 2nd heat
generator", the 2nd heat generator remains in operation for at
least 30 hours. If the heat consumption is reduced during this
period, the 2nd heat generator goes into "Active stand-by
operation" (2nd heat generator voltage on, but Mixer CLOSED).
It is not fully switched off until there has been no request for the
2nd heat generator for a period of 30 hours.
9.4.5
Bivalent - renewable
When integrating a renewable heat source (e.g. solar, wood),
this must be given priority over heat pump operation (see Fig. 2.3
on p. IV). This is done by coding to bivalent-renewable in the
preconfiguration. As long as the renewable cylinder is cold, the
system responds like a mono energy system.
The sensor for the renewable cylinder is connected to the
analogue input N1-B8. The mixer outputs of the bivalence mixer
are active.
NOTE
Heat pumps which are not equipped with an integrated flow sensor must
be retrofitted (N1-B5).
Basic function:
The temperature in the renewable cylinder is measured and
compared with the flow temperature of the corresponding
request (domestic hot water, heating or swimming pool). If the
temperature is above the conditions listed below, the heat pump
is blocked, the renewable cylinder is used as the 2nd heat
generator and the bivalence mixer is activated accordingly.
Block by heating request:
If the temperature in the cylinder is 2-20 K higher than the
current flow temperature, the heat pump is blocked when there is
a pending heating request. It is not enabled again until the
difference between the renewable cylinder and the flow is less
than half of the switching value.
NOTE
When integrating solar heat sources, adjust the set overtemperature to
the maximum value to prevent the heat pump from surging.
9.5 Power Regulation
The heat pump manager can define a maximum of 3 power
stages, L1, L2 und L3, which it switches depending on the heat
consumption. Rising heat consumption causes the next highest
power stage to be switched, falling heat consumption the next
lowest.
L1:
Heat pump operates with one compressor
L2:
Heat pump operates with two compressors
EN-28
dissipation of the boiler. If the system is equipped with
atmospherically controlled burner regulation, the voltage supply
for burner regulation should be disconnected in the case of heat
pump only operation. The boiler control must be connected to the
2nd heat generator output of the heat pump controller, and the
operating mode of the 2nd heat generator coded as being
"variable". The characteristic curve of the burner regulation is set
according to the heat pump manager.
This function can be used in bivalent systems as follows:
1)
To prevent corrosion damage with older oil or gas boilers
due to frequent undershooting of the dew point.
2)
To ensure that with main cylinder systems, tank charging for
the following day is independent of the current heat
consumption.
Block by request for domestic hot water:
If the temperature in the cylinder is 2 - 10 K higher than the
current hot water temperature, the heat pump is blocked by a
pending request for domestic hot water. It is not enabled again
until the difference between the renewable cylinder and the hot
water is less than half of the switching value.
Block by request for swimming pool water:
If the temperature in the cylinder is higher than 35 °C (value is
adjustable from 10 – 50 °C in the menu "Settings - 2nd heat
generator - Overtemperature"), the heat pump is blocked when
there is a pending swimming pool water request. It is not enabled
again until the temperature in the buffer tank connected in
parallel is 5 K under the switching temperature.
As soon as one of the three blocks described occurs, the heat
pump is blocked, and the following message is displayed: HP
waiting, Block BR. The 2nd heat generator output is not
activated.
Mixer control:
If there is no block by bivalent-renewable, the mixer is switched
to continuously CLOSED.
If there is a bivalent-renewable block because of domestic hot
water or swimming pool, the mixer is switched to continuously
OPEN.
If there is a bivalent-renewable block because of heating, mixer
regulation is active.
L3:
Heat pump operates and 2nd heat generator is active
(not with monovalent systems)
The heat pump manager always starts in power stage L1
after start-up or a power failure.
The power stages are not redefined during defrosting,
preparation of swimming pool water, a request for domestic
hot water or a utility block.
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