Note: 1.This machine can be used with Single-phase 220V or dual-phase 110V 2.please confrim the wire referring to the power of the unit,here are the current of different type of machine 9KW/220V = 41A,about 41A 11KW/220V =50A, about 50A 15KW/220V =68A,about 68A 18KW/220V =82A,about 82A Specifications: Liner material: stainless steel Voltage: 220V (Transformer required) Power: 11KW Phase: single phase Connection size: 40 mm (1.57 ") Machine size: 49 x 10 x 38 cm / L x W x H. Suitable for: hot tub & swimming pool equipment Description: Intelligent temperature control, stable performance, safe and reliable Automatic constant temperature, can be set according to the required water temperature. The maximum set temperature is approx. 55 ℃. Safe and reliable, mechanical pressure switch. When the pressure is below the set value, the power supply is automatically switched off. Do not heat sea water or salt water. The thermostat must work with a water pump with an appropriate capacity. 5.5KW-15KW heaters must operate with a pump with a water flow of at least 177 ft³ / hour (5m³/hour). 18KW-36KW heaters must operate with a pump with a water flow of at least 353 ft³ / hour (10m³/hour). 40KW-60KW heaters must operate with a pump with a water flow of at least 530 ft³ / hour (15m³/hour). 5.5KW thermostat is suitable for ≤ 127 ft³ pool / 3.6m³ The 9KW thermostat is suitable for a pool with ≤ 212 ft³ / 6m³ The 11KW thermostat is suitable for a pool with ≤ 259 ft³ / 7.3m³ The 15KW thermostat is suitable for a pool of ≤ 353 ft³ / 10m³ The 18KW thermostat is suitable for a pool with ≤ 424 ft³ / 12m³ Package in