Return visit to inspect rtu operation, after further diagnostics I found that the rpm sensor on the exhaust motor was no longer operating correctly, I confirmed this with the manufacture. I managed to track down a exhaust motor kit that included the sensor and placed on order right away. Once we receive the parts we will reach back out to confirm a new appointment to return and make the needed repairs. As of now since the system cannot start up fully, I cannot confirm that this is the only issue.