PoolControls Zenheat ZHT21 Vertical Airflow Inverter Pool Heater with R32 Refrigerant

For residential pool and spa heating, the Zenheat ZHT 21 uses a fully inverter air-source heat pump with R32 refrigerant and a titanium heat exchanger. Air is discharged vertically through the top of the unit, while automatic defrosting is provided through a 4-way valve. The ZHT 21 is specified for a 220–240V, single-phase, 50Hz power supply.

Maximum power input is rated at 3.2 kW and maximum current at 14.7 A, with a specified water flow volume of 6.5 m³/h. The heater has a working temperature range of -15°C to 43°C, establishing the operating temperature conditions stated for this model. These electrical and water-flow ratings represent the highest specified values within the four ZHT models covered by the datasheet.

The unit is housed in an ABS casing with an IPX4 waterproof level. Noise is specified at 45–56 dB(A) at 1 metre and 25–36 dB(A) at 10 metres. Its net weight is 61 kg and gross weight is 72 kg, providing the product and packaged weights relevant to handling and installation planning.

The ZHT 21 has net dimensions of 650 × 650 × 770 mm and package dimensions of 680 × 720 × 910 mm. These dimensions establish the physical size of the heater and its packaged form, while the enclosure accommodates the integrated heating and control components specified for the ZHT configuration.

Features

• A high-end Mitsubishi compressor is used within the ZHT 21 heating system.
• The fully inverter configuration carries the brochure's COP of up to 16.
• Built-in WiFi provides connectivity for the heater's control functions.
• The premium touchscreen display provides the main interface for operating the unit.
• Heating, cooling and automatic modes provide the specified operating choices.
• Multi-protection functions form part of the system's operating configuration.
• The titanium heat exchanger provides the specified heat exchange arrangement.