Normally Hot water from Nano should be around 80-85⁰C in temperature. What can you do if your hot water is much colder? Here are some solutions:
In some cases, Nano is polarity sensitive. Try to flip the Nano power plug to change the polarity.
If you read this text on the Nano display, it means your power plug is connected in the wrong way. The heater unit of Nano is phase sensitive, so you need to insert the plug in the right direction.