This unit has served the oilfield for over 10 years, but lacked the timely, thorough overhaul. In order to ensure the production to be completed smoothly, He'nan Oilfield invited Jereh Company to maintain this unit. Jereh Company accepted this maintenance in August, 2002. The vehicles needing overhauling include 5 frac pump trucks, 2 blenders and 1 Instrument Truck. The items are overhauling the deck engines, maintaining the chassis, overhauling all the electronic circuits of 2 blenders, changing all the instruments and gauges. The maintenance of this unit is carried on smoothly.