If the hot water supply temperature is 170 and the return temperature is 150, does this meet the required delta-T of at least 20 degrees?

• A. Yes
• B. No
• C. Cannot Determine
• D. Only If Higher

Answer: (A)

Delta-T is the difference between the hot water supply and the return temperature. Here, 170 minus 150 equals 20 degrees. Since the requirement is at least 20 degrees, a delta of 20 meets the requirement exactly. So this configuration satisfies the delta-T rule.