• 01
  • 01

Forced Circulation Systems

MEGASUN Forced Circulation Solar Heating Systems

Ensure maximum performance with minimum cost with our high-standard forced circulation systems.

Why should we use a Solar Water Heating System?

A solar heating system is ecologically friendly. It is economical, simple to install, tasteful, effective and autonomous:

  • Ecologically friendly: with a MEGASUN VS 500E system, the emissions of C02 avoided annually are equivalent to the fuel emissions of a car having run for 10.000 km
  • Economical: will decrease your cost for energy by 70 -100% because the burnerand electric resistance will not need to operate for at least 7-12 months of the year, depends on the sun radiation of each area and the size of the system.
  • Simple: The well-studied selection of materials of MEGASUN make. Its Installation safe and easy, reducing the time needed for its installation to a minimum.
  • Tasteful: The excellent exterior design of the MEGASUN collectors in combination with their well-studied support base, offer the possibility of a tangent Installation on tiled roofs matching aesthetically with every architectural building design.
  • Effective and Autonomous: You have hot water at will 7-12 months per year. During winter time you secure the pre-heating of the water, and the extra hot water needed is secured from conventional energy.

The forced circulation system MEGASUN consists of the following components:

  • Boiler with one tube heat exchanger (type VS-BL1) or with two tube heat exchangers (type VS-BL2) on a wooden palette and wrapped with stretch film.
  • One (1), Two (2), or Three (3) collectors which are protected during their transport with 4 plastic elbows of hard plastic.
  • Cardboard box with all of the accessories (except pipes and wires) which are required for the installation of the system like hydraulic kit, expansion pot, differential thermostat with plastic case, antifreeze liquid and various connection accessories in individual plastic packaging. Externally the box refers to the model of the system for which the accessories are for.
  • Cardboard box with the metal plates of the support base, the screws, moly plugs, the bolts etc.

Forced Circulation Systems

Download the pdf Click here to download the pdf for the Forced Circulation Systems

Drinking Water Quality Certificate pdf Certificate for drinking water

  • Solar Panels (Collectors)

    Solar Panel Models ST-2000 & ST-2500 SELECTIVES (Titanium)

    Solar Collectors
    Flat solar collector, firmly built, of new technology suitable for all forced circulation solar systems.
    The production process and the raw materials that are used produce a high thermal energy efficiency even during periods with insufficient radiation.


    The MEGASUN solar panels are produced in two types, ST-2000 (2,10 m2) and ST-2500 (2,61m2), with black paint coating or a blue titanium selective, which either in solo or in combinations cover all of the requirements of solar systems.

    Basic Technical Characteristics

    • Frame made from stainless aluminum, which is extremely durable to adverse climatic conditions (high humidity - coastal areas).
    • Strong side and back insulation (20mm glass wool and 40mm rock wool), minimize thermal losses in areas with low seasonal temperatures.
    • Special prismatic glass, resistant to hale (solar tempered glass).
    • Absorber made from copper treated with a blue colour titanium selective coating or with black paint. The absorber with titanium coating is ideal for regions with high diffused radiation and low temperatures, absorbing up to 16% more solar radiationin winter months compared to simple black chrome absorbers. This method of coating is non toxic and does not pollute the environment, while keeping stable its mechanical and optical properties during high and low temperatures.

    Dimensions of Solar Panels (Collectors)

      ST-2000 ST-2500
    Dimensions (mm) 2050 x 1010 x 90 2050 x 1275 x 90
    Gross Surface 2.10 2.61
    Net Surface 1.8 2.31
    Weight (kg) 43 51
    Capacity (L) 1.67 2.09
    Test Pressure (bar) 10 10
    Max. Working Pressure (bar) 7 7
    Absorber a 95%±2% 95%±2%
    Absorber e 5%±3% 5%±3%


    Solar Panel Models ST-2000 & ST-2500 SELECTIVES (Titanium)

    Solar Panel SelectiveSolar Collectors

    Technical Characteristics

    • Absorber: a unique sheet of aluminium
    • Thermal Absorption: 95%
    • Thermal loss: 5%
    • Thickness: 0,2mm
    • Coating: selective titanium

    Characteristics of the tubes

    • Diameter of the horizontal tubes: (∅22mm)
    • Diameter of the vertical tubes: (∅10mm or ∅8mm)
    • Material: copper
    • Test Pressure: 10 bars
    • Maximum functional pressure: 7 bars


    • Material: heavy aluminum profile
    • Back insulation: 35-40 mm insulation
    • Side insulation: 20 mm glasswool


    • Material: solar tempered glass
    • Thickness: 3,5mm or 4mm
    • Watertightness: joint EPDM and transparent silicone

    General Characteristics

    • Total thermal efficiency: 95% ± 2%
    • Total thermal losses: 5% ± 3%
    • Antifreeze: glicol appropriate for solar systems

    Support base
    The characteristics of the support base for the collector(s) with the ways of installation on the various types of roofs, are described analytically on page 32, Chapter 5, Installation Instructions.

    Download the pdf Download the pdf to view dimensions of installed collectors

    Download the pdf Download the pdf for Installation Instructions

  • Solar Boilers

    Cost-effective, durable boilers ideal for home and professional use made by quality, eco-friendly material.

    Vertical Storage Tanks On this page you are provided with information, specifications and technical data about the Megasun Vertical Boilers provided by Solarnet S.A. Boiler Storage Tanks Manufacturer.

    “Megasun Boilers” are manufactured in a variety of types and can be also used as hot water storage tanks. They comply to DIN 4753 and EN 12897 specifications, are tested according to the international hygiene regulations and have a capacity ranging from 150 to 5000 liters.

    Megasun hot water boilers are ideal for home use as well as for hotels, offices, mansions etc, are provided with single, double, triple power source with buffers and are available in 5 different colors. Their insulation of high density cast polyurethane is eco friendly and ensures hot water for longer. Furthermore, Megasun hot water boilers are the fastest on the market due to their large heat exchanger, making them also cost-effective.

    The types of vertical hot water boilers and storage tanks are the following:

    • Type BL0, without coils (150, 200, 300, 420, 500, 800 & 1000 litres)
    • Type BL1, with one coil heat exchanger (150, 200, 300, 420, 500, 800, 1000, 1500, 2000, 2500, 3000, 4000 and 5000 litres)
    • Type BL2, with two coil heat exchangers (150, 200, 300, 420, 500, 800, 1000, 1500, 2000, 2500, 3000, 4000 and 5000 litres)
    • Type FRW1, (Fresh Water) 150L - 200L - 300L Hot water tank for heat pump - solar water heaters

    General Characteristics of Megasun Hot Water Boilers

    Water Storage Tanks:

    • Material: Steel plate USD37.2 quality
    • Welding: Robotically welded in inert gas environment
    • Cleaning: 6 point metal blasting
    • Internal protection: Glass enamel baked at 850° C
    • Function Pmax: 6 bar
    • Testing Pmax: 15 bar for 5 minutes
    • Function Tmax: +95° C


    • Material: Polyurethane CFC & FCKW Free
    • Density: 40 kg/m3
    • Thickness: 65 mm

    (For storage tanks 800, 1000, insulation is made from flexible polyurethane 70 mm and is detachable for easier passage during installation)

    Outer Cover Material: PVC in various colors

    Heat Exchanger Type:Coil heat exchanger made of heavy duty steel tube 33mm (tubo).

    Electrical Backup (upon request): 2 kw to 4 kw (220-240V, one-phase) with thermostat or 6 kw, 9 kw ή 12 kw (three-phase, 380V) without thermostat.

    Description of BL0, BL1, BL2, BUFFER & FRW1 Storage Tanks

    Tank weights when empty (in KG)

    Litres / Type BL0 BL1 BL2 BUFFER-0 BUFFER-1 BUFFER-1
    150 51 64 69 43 66 - 49
    200 68 85 93 60 85 - 66
    300 94 108 128 90 118 - 96
    420 118 146 156 108 132 - -
    500 122 165 182 117 150 162 -
    800 137 176 210 127 168 180 -
    1000 162 201 235 152 198 210 -
    1500 - 494 520 - - - -
    2000 - 572 590 - - - -
    2500 - 750 760 - - - -
    3000 - 845 870 - - - -
    4000 - 1280 1390 - - - -
    5000 - 1485 1620 - - - -


    ASSOS BOILERS buffer tanks

    Hydraulic Connections BL1:

    Volume 1500 - 2000 - 2500 - 3000 - 4000 - 5000 L
    1 Hot water outlet 2"
    2 Collector or Heater Inlet 1 ¼”
    3 Recirculation connection 1 ¼”
    4 Collector or Heater Outlet 1 ¼”
    5 Cold Water Inlet 2"
    6 Discharge 1 ¼”
    7 Cleaning Flange Φ170
    8 Electric Back-up inlet * 3 Χ 1 ½"
    9 Position for Control Panel  
    10 Sensor inlet 1/2"
    11 Magnesium rod  
    * For the Boilers of 2000 ltrs and over there is the posibility of installing of a third electric resistance too under the cleaning flange.

    Hydraulic Connections BL2:

    Volume 1500 - 2000 - 2500 - 3000 - 4000 - 5000 L
    1 Hot Water Outlet 2"
    2 Heater Inlet 1 ¼”
    3 Recirculation Connection 1 ¼”
    4 Heater Outlet 1 ¼”
    5 Collector Inlet 1 ¼”
    6 Collector Outlet 1 ¼”
    7 Cold Water Inlet 2"
    8 Discharge 1 ¼”
    9 Cleaning Flange Φ170
    10 Electric Back-up inlet * 3 Χ 1 ½"
    11 Position for Control Panel  
    12 Sensor Inlet 1/2"
    13 Magnesium rod  
    14 Sensor Inlet 1/2"
    * For the Boilers of 2000 ltrs and over there is the posibility of installing of a third electric resistance too under the cleaning flange.

    Thermal Insulation:

    • Polyurethane Foam CFC & FCKW free
    • Density: 40 kg/m3
    • Thickness: 65 mm
    • Thermal Conductivity: 0,023 W/mk
    • Fire Class: Β3, auto extinguishable

    Hydraulic Connexions BL:

    Volume 150 L 200 L 300 L 420 L 500 L 800 L 1000 L
    Sensor 1/2" 1/2" 1/2" 1/2" 1/2" 1/2" 1/2"
    Heat exchangers 1" 1" 1" 1" 1" 1" 1"
    Hot-Cold inlets 1" 1" 1" 1" 1" 1" 1"
    Electric Element 1½" 1½" 1½" 1½" 1½" 1½" 1½"
    Recirculation 1" 1" 1" 1" 1" 1" 1"

    Hydraulic Connexions FRW1:

    Volume 150 - 200 - 300 L
    Position sensor DHW 1/2"
    Location Solar sensor 1/2"
    Supply flow - Return from heat pump 1"
    Supply flow - Return from solar panel 3/4"
    Cold water entrance 3/4"
    Hot water outlet 3/4"
    Electric resistancee 1½"
    Air ventilator 1/2"

    *option upon request

    Corrosion Protection Inner cleaning of the tank with automated sand blasting (notchemically) resulting in a perfect adherence of the enamel. Food grade enamel quality applied with a “double direct” method and baked at 850° C. Extra corrosion protection is offered by magnesium rods that must be checked and replaced if necessary every 6 months to 2 years, depending on the quality of the water.

    Backup Heating Source If solar power is not sufficient to warm the water, a backupheating source can be used, either through an electric element or another heating source (central heating burner) that will be connected to the upper heat exchanger (BL2 models).Control of the electric element is made through the built in thermostat. It is recommended the thermostat be positioned between 50° C and 60° C during winter months and between 45° C and 50° C during summer.


    Control: incorporated
    Model of thermostat: B2-10
    Protection at IP: 00
    Tmax - maximum environmental temperature: 105 ºC
    Cycles start / pause: 10.000 times (cycles)
    Fire resistance category: B
    Environmental function: Clean Εnvironment
    • Regulation: between 30° C - 80°C
    • Contacts: bakelite – silver
    • Protection cap from nylon 6 (flame retardant).
    • 230 V /20 A

    Backup Heating Source Using the Second, UpperHeat Exchanger Coil type heat exchanger, from heavy duty steel (type Tubo) integrated in the upper part of the tank, in order for the secondary heating source to heat only the upper part of the tank. Further technical data concerning the upper heat exchanger refer to the table concerning BL2 tanks.

    Download the pdf Typical Applications

    Download the pdf Installation Instructions

    Download the pdf Technical Specifications

  • Hydraulic Kit

    Hydraulic Kit Hydraulic KitHydraulic Kit

    Used as a pump, regulator and air venting valve in solar heating systems. With the hydraulic kit, hydraulic balancing, flow measurement and venting can be performed directly in the station. The built-in SETTER Inline UN allows the required quantity of fluid in the primary circuit to be exactly and simply set and checked. The continuous venting system meets the most demanding requirements and keeps the system free of air.

    Systems which are correctly balanced hydraulically and air-free guarantee optimal energy extraction, and are thus more cost-effective in the sense of the energy-saving directives laid down by law. Using the scale, which is pre-calibrated for glycol, the technician can set and check the exact flow-rate values on-site. Neither training courses nor expensive measuring devices are required. Installation and venting can be carried out by one person working unaided.

    Download the pdf Download the pdf to view details about Hydraulic Kit.

    Download the pdf Download the pdf for Installation Instructions

  • Differential Thermostat

    Differential Thermostat TDC 1 PLUS         


  • Peripheral Accessories

    Hydraulic KitDifferential Thermostat TCD1 PLUS Expansion potAntifreeze LiquidElectric Resistance

    All of the necessary connection accessories of each unit are located in an incorporated packaging. There are also optional peripheral accessories, such as thermostats and electric resistances which may be purchased separately.

    Download the pdf Download the pdf to view details about all peripheral accessories.

    Download the pdf Download the pdf for Installation Instructions

  • 1

Greek Products

solar water heater with horizontal collectors



Nea Zoi, Aspropyrgos
19300, Attiki, Greece

Tel. +30 (210) 5595624
or 5595625 or 5595626
Fax: +30 (210) 5595723
E-mail: megasun@helioakmi.com

About Us

Factory of production of solar panels, storage tanks, solar heaters and boilers.


National Award

International Recognition with proofs

The Netherlands
The Netherlands
European Union
European Union
European Union
European Union
ISO 9001-2008 TUV NORD
ISO 9001-2008 TUV NORD
South Africa
South Africa
European Union
European Union