When the TEMP CONTROL switch is moved towards HOT, what happens to the heat exchanger bypass valve?

When the TEMP CONTROL switch is moved towards HOT, the heat exchanger bypass valve opens allowing more warm air to bypass. In a typical aircraft heating system, such as that found in the T‑6B, this action is crucial for regulating cabin temperatures.

When the valve opens, it redirects more air that has not been heated through the bypass, effectively increasing the amount of cooler air that mixes with the warm air being circulated into the cabin. As a result, this can enhance passenger comfort by allowing the temperature to be adjusted based on the specific heating needs during flight.

The design of the heat exchange and bypass system ensures that when the desire for heat is increased, the bypass valve's opening allows for maximum thermal adjustment, contributing to a more effective and responsive heating system overall.