World famous scroll compressor for reliability and superior performance. High efficiency eco-friendly R134A, R417A or R407C refrigerant, without ozone depletion. Intelligent control: micro processor based digital controller with LCD display. Adjustable water temperature setting: 25°C-60°C. hydrophilic aluminum fins to resist corrosion. Back-up heating element for emergency (optional). Inner grooved copper tube for higher efficiency. Water heat exchanger: tube-in- shell for cycle heating models, and tube-in-tube for direct heating models. Alco or Danfoss thermal expansion valve, Advanced flow control devices for direct heating models. 50Hz and 60Hz units all available.