How is the electric heating element for the water tank controlled? Via the controller? Is it necessary to have different modes of operation for peak/off-peak hours?

The electrical resistance integrated in solar storage tanks usually works via an integrated thermostat and is independent of the regulation.

It is not necessary to install a peak/off-peak operation device, however it can allow you to pay less for your electricity (by using the resistance only during the night - i.e. in off-peak hours - for example).

Furthermore, using the electric resistance only at night has the advantage of giving priority to the heating of the balloon by the solar panels during the day. This allows you to take better advantage of the solar panels.

We would like to remind you of the special features that the solar storage tanks of DualSun systems must comply with:

What hot water tanks should be used with DualSun panels?


The "DualSun SLL" solar controller allows the electrical resistance of the hot water tank to be controlled more precisely by means of three programmable time slots in the controller.



(1) = Auxiliary power relay for single-phase 230V electrical resistance

  • 1 contact NO - 20A (normally open)
  • 1 contact NF - 20A (normally closed)

(2) = 3-phase auxiliary power relay for 400V three-phase electrical resistance

  • 4 contacts NO - 40A (normally open)

(3) = Relay output R2 must be configured in OnOff mode (REL ... REL2 .... ONOF)


System parmeter = 3

  • Place S3 probe at the top of the water tank
  • Wire the resistance on contact NO (normally open) of the power relay.

In CA menu of the controller:

  • Use of relay R2 with thermostat function taking the probe S3 as reference and with time range to be defined.
    • CAO = 40°C
    • CAF = 55°C
  • Example of scheduling according to household profile, shower in the evening or in the morning.
    • Evening: t1O = 15h00 ; t1F = 22h00
    • Morning: t1O = 3h00; t1F = 8h00
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