Section 8: Operation Page 39
8.3 Water Pump Management
8.3.1 Main water pump
Fundamentally, the ON/OFF of the main water pump links to ON/OFF of
the compressor, but the setting ON/OFF of the pump during compressor
OFF states, due to reaching the room set point shall be set in the following
parameters:
• Always ON, apart if any alarms are active or if the heat pump is in OFF
mode
• ON/OFF based on thermal store temperature
• ON/OFF based on detect cycle
If the thermal store temperature probe is enabled, the main water pump turns
ON if the thermal store temperature is lower than outgoing water set point
(fixed or calculated by climatic curve) – hysteresis, in heating mode. When
the thermal store temperature reached the set point (fixed or calculated by
climatic curve), the main pump turns OFF.
8.3.2 Continuous operation “Always ON”
When the heat pump is set to “heating” (i.e. not in standby) the main water
pump will always remain ON.
When the heat pump is set to standby, the pump will remain OFF and will
only be started in the conditions described in paragraph in Section 8.3 (Frost
protection).
8.3.3 Detect operation “Detect cycle”
In order to minimise energy consumption, the main water pump can be
configured to start only when there is demand from the temperature controller.
The pump will be activated periodically, for a time set by parameter. Five
seconds before the cycle ends, if the outgoing water temperature is lower than
“water set point – hysteresis”, the compressor will be activated and the pump
will remain ON. When the compressor stops, the pump will continue running
for a time set by parameter, after which it will be switched OFF and will repeat
the detect cycles.
The interval between one detect cycle and the next is set by a parameter.
Refer to Figure 8-6 (detect cycle).
8.3.4 Warm Weather Operation
At ambient temperatures exceeding the maximum outdoor air temperature
setting (Te2) – Parameter 2105, the weather compensation function will not
allow the heat pump to operate to provide space heating.
To override this and force the operation of the heat pump (e.g.
to check operation or commission the heat pump) parameter
2100 must be set to 0. With this setting the heat pump will
operate at a fixed set point of 45°C irrespective of the outdoor
air temperature.
If the weather compensation function is required, Parameter 2100 must
be reset to 1 once the heat pump has been commissioned or its operation
checked.
Delay time
OFF
Time OFF Time ON
(3min) (5min) (3min)
(5sec)
Water temp. detect
Compressor ON
OFF
Main water pump ON
OFF
Figure 8-6: Detect cycle
Table 8-7: Detect cycle parameters
Level
Parameter
Function description
Display and input value
Remarks
Group Code Default Min. Max. Unit
I 42 00
Type of configuration of Main water pump
0=always ON
1=ON/OFF based on thermal store temperature
2=ON/OFF based on Detect
0 0 2 -
To be set to
the following
combinations
Parameter 5111=0
→Parameter 4200=0
or 2
Parameter 5111=1
→Parameter 4200=0
or1 or 2
I 42 01 Time ON main water pump for detect cycle 3 1 15 1min
I 42 02 Time OFF main water pump 5 5 30 1min
I 42 03 Delay time OFF main water pump from OFF compressor 3 1 15 1min
I 51 11
Terminal 11-12 : thermal store temperature probe
0=disable
1=enable
0 0 1 -
For details of how to access the parameter settings, refer to Section 9.3.
The ‘detect cycle’ is allowed only for space
heating. If the heat pump is working to
produce DHW the main water pump has to run
continuously.
NOTE
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