Control on DHW 3-Way Valve for SDDC dc inverter heat pump

The version of program involved in this article was only applied to those split type air to water SDDC dc inverter heat pump produced after Oct. 2018.

What is SDDC dc inverter heat pump?

They were produced by Zhongshan SUNDEZ Eco-Energy Solution Co., Ltd

The related models:

SDDC-075-BSDDC-125-BSDDC-125-B-S

Three key factors for DHW heating function to be ready:

  1. DHW sensor had been correctly positioned;
  2. DHW 3-way valve had been installed correctly;
  3. Heating+DHW mode had been selected on LCD controller panel.

DHW heating is prior to house heating when Heating+DHW mode has been activated.

The control output signal from PCB mainboard:

When DHW heating, 3-way valve has no power input;
When house heating, 3-way valve has power input;

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