Recreational Vehicle (RV) Technician Practice Test

A propane timed pressure drop test may be invalid if which of the following occurs?

1. Piping temperature increases during the test

2. The pressure drops too quickly

3. The system is completely filled with propane

4. No leaks are detected

The correct answer is: Piping temperature increases during the test

A propane timed pressure drop test is a crucial procedure used to ensure there are no leaks in a propane system. For this test to provide accurate and reliable results, certain conditions need to be ideal during the test duration. When the temperature of the piping increases during the test, it can significantly affect pressure readings. Propane is a gas that responds to temperature changes, meaning that as the temperature rises, the pressure can also rise due to the gas expanding. This expansion can create the illusion of a drop in pressure due to leaks when, in fact, the change is solely due to thermal expansion caused by increased temperature. Therefore, if the temperature increases during the test, it may invalidate the pressure drop results and lead to a false conclusion about the presence of leaks or the integrity of the system. The other options, such as a rapid pressure drop, a system filled with propane, or no leaks detected, do not directly correlate with the validity of the test in terms of temperature's effect on measured pressure. Therefore, it is critically important to monitor conditions, particularly temperature, during a propane timed pressure drop test to ensure accurate data and safe operations.