TM 10-7310-281-13&P MODERN BURNER UNIT (MBU)            0005 00 OPERATION UNDER USUAL CONDITIONS 0005 00-22 Table 1. MBU Fault Indicators Indicator - color Indicator Normally Lit If Lit Before Operation If Lit While MBU Is Operating If Lit After Automatic Shutdown WARMUP - amber First two minutes of MBU operation. N/A Normal first two minutes of operation, abnormal after two minutes. N/A RUN - green After two minutes of operation. WARMUP indicator tuns off at the same time. N/A Abnormal first two minutes of operation, normal after two minutes. N/A FUELING/FULL (green) blinking/steady When fuel tank is filling/full. N/A N/A N/A LOW FUEL – indicators light  as follows: After approximately 3 hours of operation, and for ½ hour thereafter, for the times indicated: - green (blinking) For 15 minutes - amber (blinking) For 7-1/2 minutes - red (blinking) For 7-1/2 minutes - red (steady) On MBU shut-down, hour from when LOW FUEL initially blinked green. Fuel tank needs to be filled. NOTE! If the MBU is manually shut down while the Low Fuel indicator is lit, it will not restart until it is refueled. VOLTAGE (red) At an automatic shutdown when supply voltage falls to less than 22 V DC or greater than 29.5 V DC. Check power source for proper operation. N/A Check power source for proper operation.. SERVICE  (red) Troubleshoot the problem (WP 0009).  Attempt a re-start of MBU. HOUR METER BACK LIGHT -green When power is on. N/A N/A N/A