Operation manual of solar controller SR658
Page 27 of 105
System 12: Solar system with 1 collector field, 2 tanks, valve logic, heating return
loading
Description:
The controller calculates the temperature difference between collector sensor T1 and 2
tank’s sensor T2 and T4. If the difference is larger than or identical to the adjusted switch-on
temperature difference, then solar circulation pump (R1) will be switched on, and
simultaneously valve R4 turns to the corresponding tank, and this tank will be loaded until the
switch-off temperature difference or the maximum tank temperature is reached.
The priority logic effects prior loading of the tank 1.
Please refer the Paragraph of "LLOGI Tank priority logic"
By using another temperature difference between T5 and T6 controls valve R5 to load the
heating return flow.
Please refer the Paragraph of "RPH Heating return pipe preheat"
Sensor Description
Relay Description
T0
Temperature of heating return
R1
Solar circulation pump 1
T1
Temperature of collector
R2
1. TIMER
（
Timer function
）
2. OPARR
（
Parallel relay
）
3. Thermostat function
4. OHDP
（
Thermal transfer
）
T2
Temperature of tank 1 base
T3
Temperature of tank 1 upper
(optional)
T4
Temperature of tank 2 base
R3
1.SFB
（
Solid fuel boiler
）
2.CIRC
（
DHW circulation
T5
Temperature of tank 2 upper
(optional)
R4
Valve of solar circuit
T6
Sensor for DHW temperature or
for flow switcher (optional)
R5
Valve of heating return
T7
Temperature for thermal energy
measurement (optional)
HR
Back-up heating
