For an efficiency test, how long must the burner run to reach steady state conditions?

To determine how long a burner must run to reach steady-state conditions for efficiency testing, it is essential to allow sufficient time for the system to stabilize. Steady-state condition refers to the point at which the system's temperature, combustion efficiency, and other performance indicators become consistent over time after initial fluctuations due to startup.

Running the burner for five minutes is commonly accepted as the duration required for it to reach these stable operating conditions. During this period, the burner will achieve a uniform temperature and combustion profile, allowing for accurate measurements of efficiency without the variations that can occur immediately after startup.

A shorter duration might not capture all necessary operating factors, leading to possibly inaccurate readings. Therefore, five minutes strikes a balance, allowing the technician to ensure that the burner is functioning properly and that the measured efficiency reflects the true performance of the system under stabilized conditions. Other options either suggest insufficient time or exceed what is typically necessary for reaching a reliable steady state.