What was found
STRONG ACRID/EXHAUST SMELL BEGAN WHEN COCKPIT TEMP CONTROL WAS INCREASED TO APPROX 70 DEGREES. SUPPLY TEMP WAS BETWEEN 150 AND MAX OBSERVED OF 205 DEGREES. REMOVED AND CLEANED WATER SYS AND INSTALLED IAW MM 21-51-00 THEN RAN APU SELECTED TEMP CONTROL IN AUTO AT 65, 72, 78 DEGREES, THEN RAN ENGINES AND OPERATED ACFT IN SAME MANNER AT 65, 72, + 78 DEGREES. ALL CHECKS NORMAL. NO ODOR NOTED AT THIS TIME, ACFT OK FOR SERVICE.