Narrative:

FL410 from ZZZ; we noticed a fuel imbalance; the number two engine was 700 pounds lighter. We discovered the crossfeed valve circuit breaker (C/B) was popped and we were unable to verify its position. We ran the crossfeed selector inoperative checklist and had our lead flight attendant visually check to ensure no fuel spray from the right side of aircraft. With no fuel leak indicated on totalizers or visual; we chose to continue to our destination. But the imbalance was increasing; what seemed rapidly; with now 1;000 pounds difference between engine one and two. We elected to divert to ZZZ2 as the imbalance increased. Although we did not suspect a fuel leak at this time; as we configured for landing; a deadheading flight attendant sitting near the overwing; reported to the lead flight attendant that she thought she saw some misty spray when the flaps were lowered. As a precaution; we declared an emergency so rescue could ensure there was not an associated leak. Rescue reported no leak and we continued to the gate. Maximum imbalance was 1;300 pounds. Contract maintenance fixed all issues and released the aircraft.

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Original NASA ASRS Text

Title: During cruise; a B737-700 flight crew notices a fuel imbalance with #2 Engine fuel tank 700 LBS lighter. They discovered the fuel Crossfeed Valve Circuit Breaker (C/B) popped; but were unable to verify the valve's position. Imbalance increased to 1;300 LBS; crew declared an emergency and diverted.

Narrative: FL410 from ZZZ; we noticed a fuel imbalance; the Number Two Engine was 700 LBS lighter. We discovered the crossfeed valve Circuit Breaker (C/B) was popped and we were unable to verify its position. We ran the Crossfeed Selector Inoperative Checklist and had our Lead Flight Attendant visually check to ensure no fuel spray from the right side of aircraft. With no fuel leak indicated on Totalizers or visual; we chose to continue to our destination. But the imbalance was increasing; what seemed rapidly; with now 1;000 LBS difference between Engine One and Two. We elected to divert to ZZZ2 as the imbalance increased. Although we did not suspect a fuel leak at this time; as we configured for landing; a deadheading Flight Attendant sitting near the overwing; reported to the Lead Flight Attendant that she thought she saw some misty spray when the flaps were lowered. As a precaution; we declared an emergency so Rescue could ensure there was not an associated leak. Rescue reported no leak and we continued to the gate. Maximum imbalance was 1;300 LBS. Contract Maintenance fixed all issues and released the aircraft.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.