Is it okay to boil water in a pressure cooker with the lid hanging?

Absolutely. You can also cover it with boiling hot pot or something.

The pressure cooker itself is a pot, and water can be boiled without a pot cover, but it needs to burn faster with a pot cover, because the pressure inside can be higher than the air pressure outside when it is heated with a pot cover, and the highest temperature that the water temperature can reach when it is boiled is higher than that without a pot cover or with a pot cover, but one thing is that the air pressure inside is very high after boiling, and it needs to be gradually cooled and depressurized to be close to the air pressure outside before it can be opened, otherwise it will be dangerous, or it will be artificially discharged or passed through an exhaust hole.

Tips: the dangerous operation of pressure cooker is: after normal operation, the food inside blocks the pressure relief channel; I thought the cover was tight, but it was not fastened properly, which led to a certain air pressure and then the cover was opened; When the air pressure is high, forcibly open the cover; The pressure cooker has been aging and has been in service for an extended period;