One: There is air in it! Find a bench and find the air conditioner hidden in it from the manhole. Look at the junction box and water pipe at the end of the air conditioner. There is a small nut on the pipe above it, which will open for a while and then close! Every house needs to do this.
Two: find the water supply pipe and see if there is water in it. If not, turn off the main valve of your house and see if there is water.
. No, ask me again.