Compressor Control In Plants With Buffer Or Combi Storage Tank - Siemens RVS41.813 User Manual

Yes
Yes
Yes
Yes
Yes
Yes
Yes
1)
Heat demand comes from a storage tank (DHW, heating circuit via buffer, forced charging)
2)
Switching differential: OL => Parameter 2840: Switching differential return temperature
3)
Safety functions swtich off compressor (high pressure, hot gas, max. switch off temperature)
4)
B21 is used to release the 2
5)
Value of parameters 5810: Differential of heating circuit at OT -10°C
T => Flow setpoint; T
Vw

Compressor control in plants with buffer or combi storage tank

Control
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HVAC Products
- - ok
- ok -
- ok ok
ok - -
ok - ok
ok ok -
ok ok ok
nd
compressor stage.
=> Return setpoint
Rw
The settings apply to compressor 1 and – if present – to compressor 2.
If a buffer or storage tank is connected to the same controller as the heat pump, the
controller uses sensors B4 and B41 for control of the compressor. The switching
differential (2840) has no impact.
If there is no sensor B41, heat pump return temperature sensor B71 is used.
The setting on operating line 2841 defines whether the minimum compressor running
time (2842) is observed.
As soon as the temperature at both sensors (B4 + B41) drops 1 Kelvin below the flow
temperature setpoint, a heat request is forwarded to the heat pump. This heat request
is maintained until the temperature at both sensors reaches the flow temperature
setpoint.
T B41
ON
K
OFF
B4 Upper buffer or combi storage tank sensor
B41 Lower buffer or combi storage tank sensor
TVLw Flow temperature setpoint
K Compressors
ON Switch-on point
OFF Switch-off point
The switch-on / off points are impacted by a number of other functions (maximum
switch-off temperature, compensation of heat deficits, compressor running time
minimum, compressor off time minimum, pump prerun time, and pump overrun time).
The heat pump is switched off as soon as the buffer or combi storage tank temperature
has reached the setpoint. The minimum off time is always observed, however, even if
the temperature at the upper buffer storage tank sensor drops below the switch-on
point.
Required sensors:
User manual RVS61.843, RVS41.813
6 The settings in detail
3)
On
3)
On
3)
On
3) 4)
On
3) 4)
On
3) 4)
On
3) 4)
On
B4
OFF = TVLw
1K
ON
t
B10 T
Vw
B71 T
Rw
B10 T
Vw
B21 T
Vw
B21 T
Vw
B21 T
Vw
B21 T
Vw
CE1U2355en_02
28. September 2009
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