In delta-T measurement practice, which statement is correct?

In delta-T measurement practice, which statement is correct?

• A. Stabilization is unnecessary if the system is running
• B. It is best to take measurements immediately after turning on systems
• C. Stabilization ensures steady-state conditions before delta-T readings
• D. It only matters for outdoor measurements

Answer: (C)

The important idea is that delta-T readings should be taken only after the system has reached steady-state. When a system starts up, temperatures can swing due to fan ramping, valve positions, control changes, and changing loads. Those transients distort the actual temperature difference you’re trying to measure. Waiting for stabilization means monitoring until the temperatures stop drifting and stay within the expected range, then recording the delta-T. This makes the reading representative of normal operating conditions, not a transient spike. Stabilization matters for all measurements, not just outdoor ones, and it isn’t correct to measure immediately after turning the system on or while it’s still changing.

The important idea is that delta-T readings should be taken only after the system has reached steady-state. When a system starts up, temperatures can swing due to fan ramping, valve positions, control changes, and changing loads. Those transients distort the actual temperature difference you’re trying to measure. Waiting for stabilization means monitoring until the temperatures stop drifting and stay within the expected range, then recording the delta-T. This makes the reading representative of normal operating conditions, not a transient spike. Stabilization matters for all measurements, not just outdoor ones, and it isn’t correct to measure immediately after turning the system on or while it’s still changing.