The Aquasun 300L Non-Pressurized Solar Water Heater is a high-capacity solar hot-water system designed for large households, guest houses, rural homes, staff quarters and other gravity-fed water systems.

It uses 30 evacuated borosilicate vacuum tubes and natural thermosiphon circulation to heat water without requiring a circulation pump. The system is built around a 300-litre insulated tank with a food-grade stainless-steel inner tank for durability and hygiene.

☀️ Key Features

• 🚿 Tank Capacity: 300 litres
• 💧 System Type: Non-Pressurized / Gravity Fed
• ☀️ Collector Type: Evacuated Vacuum Tubes
• 🔵 Number of Tubes: 30
• 📏 Tube Size: 58mm × 1800mm
• 🧪 Tube Material: Borosilicate glass
• 🧱 Inner Tank: Food-grade SUS 304-2B stainless steel
• 🎨 Outer Tank: Galvanized steel with weather-resistant coating
• 🧊 Insulation: 50–60mm high-density polyurethane foam
• 🔥 Heat Retention: Up to 72–80 hours
• ⚡ Optional Backup Heater: 1.5kW–2.0kW
• 🌞 Thermosiphon circulation with no electric pump required
• 💧 Ideal for rooftop tanks and gravity-fed plumbing
• 🌾 Suitable for rural and off-grid applications
• 🧰 Includes accessories such as assistant tank, controller, heating element and magnesium rod according to the supplier.

🔥 Thermosiphon Solar Heating

The Aquasun system works through natural convection.

As water inside the vacuum tubes heats up, it becomes lighter and rises into the storage tank. Cooler water then flows down into the tubes to be heated, creating continuous natural circulation without an electric pump.

This provides:

• ☀️ Solar-powered water heating
• ⚡ No circulation pump required
• 💰 Reduced electricity consumption
• 🔧 Fewer moving parts
• 🛠️ Simpler maintenance

🧊 Long Heat Retention

The tank uses 50–60mm high-density polyurethane insulation, helping hot water remain usable for up to 72–80 hours under suitable conditions.

This helps provide hot water:

• 🌙 At night
• 🌅 Early in the morning
• 🌥️ After periods of reduced sunlight

💧 Non-Pressurized Design

This model is intended for gravity-fed plumbing, making it particularly suitable for homes with an elevated cold-water storage tank.

Best suited for:

• 🏠 Bungalows
• 🌾 Rural residences
• 🚿 Gravity-fed bathrooms
• 🏨 Guest houses
• 🏫 Staff quarters and schools
• 🌱 Farms and off-grid properties

It should not be treated as a conventional high-pressure solar heater unless the installation is specifically engineered for it. 

✅ Benefits

• Large 300L capacity
• Uses free solar energy
• 30 high-efficiency vacuum tubes
• No circulation pump required
• Stainless-steel inner tank
• Long heat retention
• Low maintenance design
• Suitable for gravity-fed systems
• Optional electric backup
• Good choice for large families and small commercial use

⚠️ Installation Notes

• ☀️ Install where the tubes receive strong direct sunlight
• 🧱 Ensure the roof can safely support the fully filled system
• 💧 Use with an appropriate gravity-fed water supply
• 🚫 Avoid connecting directly to unsuitable high-pressure plumbing
• 🔧 Professional installation is recommended
• 🧹 Keep vacuum tubes clean for good performance
• 🛡️ Use the supplied safety and plumbing components correctly
• ⚡ If using the electric backup element, ensure proper earthing and circuit protection