Hi,
A vendor came to replace my washer in a closet. He turned the switch off on the washing machine valve. He told me that he can't replace the washer because there was a running gushing water noise. I heard the noise when he pointed it out. He told us that we need to get the building water to shut off in order for them to replace it. After the vendor left, I went to check on the switch. I did not hear the gushing running water noise anymore. I'm wondering how the vendor made that noise. What did he do? Is the valve broken because I don't hear the noise anymore. How can I test whether it's the valve is broken or there was a delay in the water shutting down when the vendor turned it off? I believe I have the Symmons Laundry Mate Valves W-600. Any help is greatly appreciated.

Thanks!