302CS13C Roof Top Solar: Key Attributes

Key Features

Solahart's roof mounted tank systems save space at ground level and their elegant simplicity make them efficient and reliable. The 302CS13C collector's higher efficiency absorber with its Sputtered Selective Surface maximises the absorption of available solar energy while the closed circuit design makes it suitable for frost prone or poor water chemistry areas. The 302CS13C Envelope collector with five patents pending has been designed to meet or exceed Australian and International Standards in areas of strength and durability

The ceramic lined tank has a protective anode and the CS13C Free Heat series features additional protection. The tank is equipped with an electric booster, alternatively an in-line gas booster is available. The 302CS13C and 302CS13C Free Heat systems are installed with the HartStat OTP (over temperature protection) system to minimise over performance during periods of higher solar radiation and lower hot water draw off.

  •  Space saving roof mount design
  •  Reliable, low maintenance operation
  •  Can cut water heating energy use by up to 83%^
  •  Eligible for Government rebates and incentives


* The suggested price is comprised of RRP less the applicable solar incentive and excluding installation. Solar incentive value applies to 302CS13C system in Zone 3.

^ Energy savings of up to 75% shown are based on Australian Government approved TRNSYS simulation modelling of a Solahart 302CS13C and using a medium load in Zone 3 and apply when replacing an electric water heater. Any savings will vary depending upon your location, type of Solahart system installed, orientation and inclination of the solar collectors, type of water heater being replaced, hot water consumption and fuel tariff. Maximum financial savings off your hot water bill are achievable when replacing an electric water heater on continuous tariff.

† Solahart Warranty Details: 5/5/5 warranty; 5 year cylinder and collectors supply, 5 year parts, 5 year labour. 10/5/5 warranty, 10 year cylinder and collectors supply, 5 year parts, 5 year labour.

302CS13C Solar Specifications

Thermosiphon CS13C Closed Circuit Systems
System Model 302CS13C
Tank Model 300J
Free Heat - 300F
Storage Capacity 300 litres
Boost Capacity  150 litres
Weight Empty Tank Only  107 kg 
Weight Full Tank Only  407 kg 
A-Width* Tank Only  2.43 m
Weight Empty System  210 kg 
Weight Full System 529 kg 
A-Width* System 2.43 m

* For servicing and safe access, a space equal to the tank length should be left on the water connection end of the system and 1m (40in) should be left on the three other sides of the installation. ‡HartStat OTP is mandatory on these models in Australia and New Zealand. Systems (if installed with a HartStat OTP system) can be installed as a solar preheater with an inline Solahart gas booster water heater. Refer to the Solahart gas booster specification sheet for further details on the gas booster.

Collectors CSA2013
Aperture Area 1.8 m2
Length 1996 mm
Width 1043 mm
Height 82 mm
Capacity 1.9 litres
Weight Empty 37 kg
Weight Full 39 kg
Working Pressure  
No OTP 80 kPa
With OTP 170 kPa
Absorber Surface SCA2000 Blue Tinox sputtered selective surface
Absorber/Riser Material copper
Number of Risers 13
Frame Material extruded aluminium
Insulation Material (Base) 38 mm glass wool blanket
Glass 3.2 mm tempered low iron


Water Supply
TPR Valve Setting 1000 kPa
ECV* Setting 850 kPa
Maximum Supply Pressure  
With ECV 680 kPa
Without ECV 800 kPa
Water Connections  
Cold Rp 3/4
Hot R 1/2

*Expansion Control Valve.

Electric Boost Specifications
Heating Unit Type Copper sheath immersion element
Supply Voltage 220 V - 250 V
Recovery Rate @ 240 V and Temperature Rise Of:
1.8 8 51 39 31
2.4 10 68 52 41
2.5* 10.5 71 54 43
3.6 15 103 77 62

 * A bobbin element (2.5kW) is available for hard or corrosive water areas.


How Roof Top Solar Systems Work

Solar Operation

The 302CS13C solar system has its vitreous enamel lined solar storage tank installed on the roof directly coupled to the solar collectors. In the Closed Circuit Series, heat is absorbed by the collector and passed to the ‘Hartgard’ heat transfer liquid inside the collector. As the temperature of the ‘Hartgard’ increases, the hot fluid rises up through the collector by the Natural Thermosiphon Principle, into the heat exchanger jacket around the potable water storage tank. Here, the heat is transferred to the potable water, cooling the ‘Hartgard’ fluid. The cooler fluid is then forced back down into the collectors through the displacement action of further hot fluid rising up into the heat exchanger jacket.

Orientation of Solar Collectors

To help maximise system performance, solar collectors should be installed with an optimum orientation facing true north (in the southern hemisphere) or true south (in the northern hemisphere). Always check for true north or true south using a compass or other suitable device.

To help maximise system performance, solar collectors should be installed with an optimum inclination. This is equal to 90% to 100% of the local latitude angle when collectors are oriented within 60° of true north or true south, and between 10° and 20° if the collectors are oriented between 60° and 90° from the optimum orientation. Generally, improved summer performance is obtained from an angle of inclination less than the optimum angle and improved winter performance is obtained by an angle of inclination greater than the optimum angle. If the angle of inclination varies by 20° from the optimum angle, the solar collectors will receive about 10% less total annual solar radiation.

Frost/Freeze Protection

Solahart Closed Circuit Systems are protected against freezing or harsh water conditions by our exclusive ‘Hartgard’ fluid. ‘Hartgard’ is a blue, non-toxic, propylene glycol fluid which, when mixed with water, provides the Heat Transfer Fluid contained in the solar collectors and the heat exchanger jacket around the tank. ‘Hartgard’ is used to lower the freezing temperature of the Heat Transfer Fluid and so provides protection against freezing (Note: for the correct % of Hartgard in the Heat Transfer Fluid, refer to the section on Frost / Freeze Protection). ‘Hartgard’ is a special food grade solution and is the only solution permitted to be used in the closed circuit systems. Hartgard has been approved by the National Health and Medical Research Council of Australia.

Solar Boosting

In-Tank Boosting

An isolating switch is installed in the electrical meter box for an electrically in-tank boosted model. This should be left switched on to allow the booster heating unit to operate if required. The booster heating unit is for heating the water at times of low solar energy gain, such as during very cloudy or rainy weather, or during the colder months. The booster heating unit will only activate if heating is required and power is available from the switchboard. When the water is below the thermostat setting, the booster heating unit will turn on and heat the water. The booster heating unit will automatically turn off when the temperature of the water reaches the thermostat setting. If the water temperature drops below the setting again the booster will re-activate.

In-Series Gas Boosting

An in-series gas booster (also known as a continuous flow gas booster) can be installed between the solar water heater and the hot outlets in the house. This booster should be permanently active. The booster senses the temperature of the water passing through it: if the water temperature is above its temperature setting it does nothing; if below it will automatically heat the water up to the preset outlet temperature setting. This gas booster ensures hot water delivery for a variety of hot water demands without the need for user intervention while enabling maximum solar energy contribution to the water heating. For more information on this booster, consult the owner’s manual for the product.

Over-Temperature Protection System

The Closed Circuit Series solar water heaters have a means of controlling the maximum temperature of the water in the storage tank. These systems are installed with a ‘HartStat’ valve located between the hot outlet of the collectors and the inlet to the tank heat exchanger. This valve closes when the tank has reached a sufficiently high temperature, thereby preventing further heat transfer to the tank, and thus limiting its temperature.


Why Solahart Solar Hot Water Systems: Download

Solahart 302CS13C Solar Hot Water System Brochure: Download

Solahart In-Line Gas Booster Brochure: Download

Installation Manuals

Solahart On-Roof Solar Hot Water System Owner's Guide and Installation Manual: Download

Solahart In-line Gas Booster Owner's Guide and Installation Manual: Download

Solar Incentive Forms

Small-scale Technology Certificate Assignment Form: Download