Which of the 3 Tuotou floor heaters is the master bedroom?

There are three floor heaters, the one on the left is the master bedroom.

We can distinguish it according to the pipelines on it. Under normal circumstances, the pipeline installed on the left is used to control the room on the left, while the pipeline on the right is used to control the room on the left. . If there are many rooms, you can first close all the pipes on the water distributor, and then open them one by one. Every time you open a channel, check which room has an increase in floor heating temperature and mark it.

It will be very clear after opening them one by one and labeling them.