HDi-310 Heat Pump: Key Benefits

Key Features

The 310 Heat Pump utilises environmental heating technology to efficiently heat water using the air’s warmth, extracting heat from the air. Its advanced ‘top-down’ heating design delivers a concentrated volume of hot water available for immediate use. By using refrigerant-based technology, heat pumps can operate in any season, day and night. Our Heat Pump also comes with an electric ‘back-up boosting’ element for operation during freezing conditions to ensure that hot water is available 24/7, regardless of the weather and air temperature.

The HDi-310 Heat Pump introduces Top Down Heating, an advanced design which delivers a concentrated volume of hot water available for immediate use. This eliminates the waiting time for the entire tank to reheat, that you experience with electric water heaters.

  •  No Solar Panels
  •  Frost protected
  •  Similar efficiency to traditional solar systems
  •  Works day and night, as they don’t require sunlight



* The suggested price is comprised of RRP less the applicable solar incentive and excluding installation. Solar incentive value applies to 511310 system in Zone 3.

^ Energy savings of up to 58% to 64% shown are based on Australian Government approved TRNSYS simulation modelling using a medium load. Savings and incentives 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. 

† Warranty Details: 5 years cylinder replacement, 3 years labour on cylinder, 2 years on sealed system including labour, 1 year on all other parts and labour.

HDi-310 Specifications

Product Code 551310
Suitable for # of People (warm climate) 3 - 6
Height (A) 1870 mm
Width (B) 670 mm
Depth (C) 679 mm
Module  48 kg
87 kg
Capacity  310 lt
Power Input 1300 W
Refrigerant  R134a
Element Sizes 2.4 kW or 3.6 kW
Boost Capacity 220 lt
Water Connections & Settings  
Inlet  ¾/20 RP
Outlet  ¾/20 RP
Tank Relief Valve Setting 1000 kPa
ECV Setting 850 kPa
Maximum Mains Pressure Settings  
With ECV 680 kPa
Without ECV 800 kPa
Min. Water Supply Pressure 200 kPa



  • Cylinder: 5 years, 3 years labour, 2 years sealed system
  • Parts: 1 year, 1 year labour

How Heat Pump Water Heaters Work

Rather than using roof mounted collectors, efficient heat pump technology extracts energy from the surrounding air. Ambient warmth is used to convert the refrigerant within the sealed system into a gas. The gas is then compressed to generate even more heat which then heats the water in the tank. What’s more this process can work day or night, in sunshine and rain, all year round.

When hot water is drawn off and cold water enters the tank, the thermostat activates a fan, a compressor and a circulator. The fan draws outside air in through the air inlet louvers at the top of the water heater and the pump circulates water from the bottom of the storage tank through a heat exchanger. The operation of the compressor causes a pressure difference within the sealed refrigeration system. This pressure difference causes the refrigerant to move around the sealed system. The refrigerant enters the evaporator as a liquid. As the refrigerant absorbs heat from the atmosphere it changes state, at low pressure, from a sub cooled liquid to a super-heated vapour or gas (evaporates). The vapour then enters the compressor and obtains more heat, known as heat of compression, and passes into the heat exchanger as a super-heated vapour at high pressure.

As the refrigerant passes through the heat exchanger it gives off heat which is absorbed by the water flowing through a separate chamber inside the heat exchanger. As the refrigerant gives off heat it cools and changes state back into a liquid (condenses). The refrigerant then enters the evaporator again and the cycle is repeated. The resulting cold air is then discharged through the air outlet louvers back to atmosphere and the heated water is circulated back into the top of the storage tank. This process continues while ever heating is required until the water in the storage tank reaches a temperature of 60°C.

Electric Boosting

Ice may begin to form on the evaporator reducing the heat pump efficiency, when the ambient air temperature falls below 7°C and the heat pump has been operating for an extended period. At ambient air temperatures below 5°C, the water heater deactivates the heat pump operation and switches to the booster heating unit. During this period the evaporator will defrost if necessary.

The boost capacity in this mode is 220 litres. The water inside the tank will be heated to a temperature of 60°C by the electric booster heating unit if heating is required. The temperature setting of the sensor controlling the booster heating unit is not adjustable and is set at 60°C.

Freeze Protection

The water heater has a freeze protection system. The freeze protection system will protect the water heater from damage, by preventing ice forming in the waterways of the water heater, in the event of freezing conditions occurring.

If the water temperature at the heat pump heat exchanger falls below 3°C and the heat pump is not operating, the system will operate the circulator periodically. Water is circulated from the storage tank through the heat pump circuit, to prevent freezing in the connecting pipe work and heat pump module. During this freeze protection cycle, the circulator will operate for at least thirty (30) seconds, deactivating when the water temperature increases above 5°C. The water heater has NO WARRANTY for freeze damage if power is unavailable at the water heater.

In areas where the ambient air temperature may fall below 4°C, power must be available to the water heater at all times to prevent freezing in the heat pump circuit.


Why Solahart Solar Hot Water Systems: Download

HDi-310 Heat Pump Hot Water System Brochure: Download

Installation Manuals

HDi-310 Heat Pump Hot Water System Owner's Guide and Installation Manual: Download

Solar Incentive Forms

Small-scale Technology Certificate Assignment Form: Download