These are cold water inlet, hot water outlet, discharge port, pressure release port and power interface.
1. Cold Water Inlet: This port is used to carry cold water to the water heater for heating.
2. Hot Water Outlet: This outlet is used to supply heated hot water from the water heater.
3. Discharge Port: This port is used to discharge waste water or exhaust gases into the water heater to maintain normal operation of the water heater.
4. Pressure Release Port: This port is used to relieve pressure in the water heater to prevent damage to the water heater due to excessive pressure.
5. Power Interface: For some solar water heaters requiring electricity, this port is used to connect the power cord to power the device.