The answer to 'shut-off valve no hot water' is that a faulty or malfunctioning shut-off valve is likely the cause of no hot water. The shut-off valve controls the flow of hot water to your home's fixtures, and if it is not functioning properly, it can restrict or completely block the hot water supply.
Some common symptoms of a shut-off valve issue include no hot water at all, low water pressure, or fluctuating hot water temperature. To troubleshoot, you can try turning the shut-off valve back and forth to see if it's stuck or not fully opening. If the valve is damaged or worn out, it will need to be replaced by a professional plumber.