We had a problem with a water chiller that was shutting down several times per hour, and we called NEVA for help on checking it (refrigerant leakage in the first place). The NEVA representative could not get to our location for more than two hours because of the severe weather conditions (heavy rain). When he finaly made it to the lab, he was chatting with us about several possibilities that might result in the chiller to shut down. After that he came to a conclusion that the following reason was causing the problem: the chiller was designed for the power 220 V, 50Hz, but was operated by 208 V, 60Hz. NOTHING WAS CHECKED BY USING ANY TOOLS (!), and the technician left with this opinion.