The Joulette is the first product to market.

The Joulette is a novel thermal solar controller that incorperates many features not found on conventional controllers.


  • Conventional difference or adaptive (intelligent) control

  • 3 pump modes – temperature drop, timed and heat exchanger differential

  • Frost protection on collector

  • Overheat protection

  • re-cooling function

  • Works with digital (DS1820) sensors (supplied) and analogue PT1000 sensors (for retrofit/replacement)

  • 4 temperature sensor inputs (either digital or analogue)

  • 10 Amp (at 240V AC) switching capability

  • Less than 1 Watt power consumption

  • Backlit clear blue LCD display either graphical or textual modes

  • Battery backup for real time clock (time/date)

  • Graphical plots – for day and hour on collector, store top and bottom. Also pump frequency

  • Logging temperatures and pump activation to SD card (as CSV file). CSV files can be uploaded and displayed on Metasol website

  • Upgradable software via SD card (software upgrades available on Metasol website)

  • Expandable – can control (or be controlled by) other Metasol devices (such as immersion control and wireless adapter which are currently under development)

  • Display in either Celsius or Fahrenheit

  • Operates from a separate 12 volt plug top supply (supplied)

  • Greater than 1% temperature accuracy (accuracy varies upon range – less accurate at temperature extremes but more accurate within ‘normal’ operating temperatures)

  • Pump time and estimated energy yield calculation

  • Intuitive menu with on-screen help guide

  • Configurable for standard or custom systems – can be used on hot water, swimming pool or hot tub systems

  • 4 button keypad and LED indicators (power, logging, pump indication and strobe)

  • Audio warnings

  • Operating temperature 0 to +50 celsius



Outputs:                   Single electromechanical relay – 10 Amps rating

Inputs:                      4 PT1000 temperature sensors or 4 DS1820 digital sensors (switchable in menu option)

Power:                       1 Watt peak, 100mW typical

Backup Time:         3 Hours Typically

Accuracy:                 0.5 Degrees Celsius over 10 to 90 range (PT1000) and ±0.5°C Accuracy from -10 to 85 (DS1820)

Resolution:              0.1 Degrees Celsius, achieved with oversampling

Logging:                    Continuously every 10 seconds, all sensors and pump status

Display:                     Full LED backlit graphical LCD display 64 by 128, graphical or text only options

User Interface:       4 Buttons, confirmation sounder, 4 status LEDs

Mains:                         220/240V ac Plug Top Supply

Dimensions:             150x130x30mm