What range should the temperature of the hashboard be for it to be ideal?

What is the minimum (coldest) temperature WhatsMiner M63 series can take in?

What is maximum temperature difference between a liquid outlet and a liquid inlet of WhatsMiner M63 series?

Where does the miner measure the temperature?

How high is the chip temperature when the coolant temperature reaches 80 degrees Celsius? Is this high temperature harmful to the miner in the long term?