DCM 3: AC complete, replaced (1) 20x25x2, (4) 16x16x2, (4) 16x20x2 filters. Systems 1 and 3 are both fully functional and operating within manufacturer specifications at this time, temperatures and pressures are appropriate for outdoor and indoor weather conditions. System 2’s economizer has failed not allowing the luvers controlling the outdoor air to open causing the system to recycle return air when outdoor temperature is below indoor temperature. Recommend replacing economizer or bypassing economizer. Irregardless of repair system should function properly when outdoor temperature gets above 70*.