Worcester 6 KW Instruction Manual page 47

20.1.1 SET POINT VALUE
The heating circuit's set point value is the temperature of the flow that
the heat pump attempts to maintain. Sometimes, the measured actual
value fluctuates a bit upward and downward depending on changes in
the outdoor temperature or a large hot water demand.
The set point value specified by the customer/installer is
most often the room temperature, which is recalculated
by the control unit into a corresponding flow
temperature set point value. Under normal conditions, 1
K ( °C) in room temperature corresponds to approx. 3 K
( °C) in flow temperature.
The set point value is normally based on:
• Current curve value (the flow temperature at the current outdoor
temperature according to the applicable heat curve).
• Current curve influence through:
– Room sensor (room controller)
– Holiday
– Active program
– External control
SET POINT VALUE CALCULATION
The set point value for the heating circuit is the current curve value
adjusted with active curve influence, if any such exists.
Priority order for curve influence is:
• External control
• Active program
• Holiday
Only one of these can be active. How big the influence should be and
when to exercise it is set in the respective function.
FIXED SET POINT VALUE
A fixed set point value (not curve-based) applies in the event of:
• External set point value. The set point value is determined according
to input signal 0-10V where 1V is 10 °C and 10V is 80 °C (0V triggers
an alarm).
SET POINT VALUE LIMITATION
The calculated set point value is always checked against the permitted
temperature limits.
The applicable set point value T1 for Circuit 1 and the measured actual
value for T1 are used to activate and deactivate the heat demand.
The following applies to Circuit 2, 3...: When the actual value for the
mixed circuit's T1 is low in relation to the set point value, more heating
water is pumped into the circuit so as to maintain the set point value.
If the flow temperature has been below the set point value for a certain
period of time, there is a heat demand and the compressor produces
heat before the indoor temperature is reduced significantly. This
happens until the flow temperature is a couple of degrees higher than
the set point value. (Or because Maximum operating time for heating
at hot water demand has passed.)
Heating demand is not active during summer operation.
> General
>> Summer/winter operation
>>> Winter operation
Factory setting
Alternative
Table 72 Summer/winter operation
If On is selected, the heat pump is constantly in winter operation and
heat and hot water are always produced. Off signifies constant summer
6 720 806 768 (2013/02)
Automatic
On/Automatic/Off
operation; only hot water is produced. Automatic signifies change-over
at the set outdoor temperature.
>>> Outdoor temperature limit for change over
Factory setting
Lowest value
Highest value
Table 73 Change over temperature
The menu is displayed only if Automatic has been selected in Winter
operation.
>>> Delay before change over to winter operation
Factory setting
Lowest value
Highest value
Table 74 Delay before change over to winter operation
>>> Delay before change over to summer operation
Factory setting
Lowest value
Highest value
Table 75 Delay before change over to summer operation
>>> Direct start limit for winter operation
Factory setting
Lowest value
Highest value
Table 76 Direct start limit
In the event of change over between winter and summer
operation and vice versa, there is a certain delay to
prevent constant starting and stopping of the
compressor when the outdoor temperature oscillates
around the temperature limit.
Below the direct start limit, the control unit changes over
to winter operation without delay.
>> Maximum operating time for heating at hot water demand
The menu is not displayed if Block heating during hot water demand is
set to Yes ( Chapter 20.2).
Factory setting
Lowest value
Highest value
Table 77 Operating time heating
>> Minimum outdoor temperature
Factory setting
Lowest value
Highest value
Table 78 Lowest outdoor temperature
▶ Set the minimum outdoor temperature for the heat curve.
SETTINGS
18 °C
5 °C
35 °C
4h
1h
48h
4h
1h
48h
13 °C
5 °C
17 °C
20min
0min
120min
-35,0 °C
-35,0 °C
-10,0 °C
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