Speed Control Of The P1 Tank Circulation Pump - Rotex Solaris RPS3 P2 Operating And Installation Manual

5.2.6 Speed control of the P1 tank circulation pump

After the start sequence the Solaris R3P control systems initiate the following:
– Stepwise output reduction of P1 until the calculated nominal spread "DT" maintains the setpoint value corresponding to
image 5-3, or until it falls below the minimum flow V2 (image 5-4).
– The switch to the next pump stage is implemented after a safety time "t
If the pump output is too low, the flow in the solar panel circuit may be interrupted depending on the system or the temperature.
If the flow falls below the value "V2" for at least 10 s (image 5-4), the control systems detect a flow interruption, and the last
valid output stage is saved as the minimum pump output. Lower pump output stages are blocked.
The temperature-dependent output control of P1 is between the calculated minimum and maximum output. The spread of "T
"T " is continuously measured and compared with the nominal spread. If the temperature spread between "T
R
great, the pump output of P1 (max. 10 stages) and therefore the flow through the solar panels is increased until the nominal
spread is reached. If the spread is too low, the pump output is reduced. The actual pump output of P1 while it is running is
displayed as a percentage in the "Flow" indicator beside the measured flow value. A typical operating sequence of a modulating
solar system is shown in image 5-3.
DT
S1
S1
Fig. 5-3
A
B
C
D
V
V1
V2
Fig. 5-4
FA ROTEX Solaris RPS3 P2 - 06/2012
Set temperature difference (calculated for
operating point)
Upper set temperature difference
("temperature difference 1")
Lower set temperature difference
("temperature difference 2")
Temperature difference-dependent pump output control
Start phase
Operating phase (modulation)
Interrupted flow
Low pump output stages are automatically disabled
when flow is interrupted
Solar circuit flow
Minimum flow in start phase ("VS min")
Minimum flow in operating phase ("S flow")
Example for modulation operation with flow-caused block of low pump stages on systems with FlowSensor
" (image 5-4).
2
T Collector temperature
K
T1 Minimum temperature of storage tank ("T
T2 Booster temperature ("TK max")
T3 Switch-on inhibit temperature ("TK zul")
— Nominal spread
--- Switching limits for pump modulation
t Time
t Maximum start run time of tank
1
circulation pump ("Time PsE")
t Stabilisation period ("S time")
2
t Interruption detection period (10 s)
3
5 x Operation
"and
V
" and "T " is too
V R
min")
R
31