The answer to 'drain trap no hot water' is that a lack of hot water in the drain trap is typically caused by a problem with the water heater or the hot water supply line. This could be due to a malfunctioning water heater, a blockage in the hot water line, or an issue with the plumbing system's valves or connections.
Some common symptoms include only cold water coming out of the drain, the water heater not heating properly, or the hot water taking a long time to reach the drain. Potential solutions may involve checking the water heater, inspecting the hot water line for clogs or leaks, and ensuring all plumbing valves and connections are functioning correctly.