The answer to 'sink no hot water' is that there are several common causes, including a faulty water heater, a problem with the hot water supply line, or a malfunctioning sink faucet. Symptoms may include lukewarm or cold water coming from the hot water tap, and the issue is typically isolated to just the sink, not the entire home.
Some potential solutions include checking the water heater thermostat, inspecting the hot water supply line for clogs or leaks, and troubleshooting the sink faucet. Depending on the cause, some homeowners may be able to DIY the fix, but for more complex issues, it's best to call a professional plumber to diagnose and resolve the problem.