Solar control
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Solar control
Differential control between the collector temperature and reference temperature (e.g. cylinder
temperature) for operation of a solar circuit pump. Optional: use of a limit sensor.
Start conditions for solar circuit pump A:
1. The collector temperature T.coll. must exceed the minimum threshold T.coll. min. and must
not exceed the maximum threshold T.coll. max.
2. The adjustable differential between T.coll. and the reference temperature T.ref. (= cylinder
outlet temperature) must be exceeded.
3. T.ref. must not yet have reached its maximum limit T.ref. max.
4. An optional maximum limit T.lim. max. can also be defined for T.lim.
General enabling of the function (digital value ON/OFF)
Analogue input signal for the collector temperature T.coll.
Analogue input signal for the reference temperature T.ref.
Optional: Analogue input signal for the limit temperature T.lim.
Analogue value specifying the minimum temperature at the collector,
T.coll. min.
Analogue value specifying the maximum reference temperature, T.ref.
max.
Analogue value specifying the maximum limit temperature, T.lim.
max.
➢ In the case of cylinders with smooth tube indirect coils, it is advisable to insert the reference
temperature sensor into the heat exchanger outlet using a tee and a sensor well (see
Installation instructions / Sensor installation).
➢ If the surface area of the collector is too large, the return temperature will rise too rapidly,
causing premature shutdown of the system due to the limit at T.ref. However, T.ref will also
drop quickly through stationary fluid in the cold section of the cylinder. The pump will then
restart, with the same consequences. To prevent this cycling and to prevent overheating in
good quality stratification cylinders, an additional, optional maximum limit can be imposed
at T.lim.
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