Captain reported an Amber 'OVBD COOL FAIL' and a Status message 'INBD COOL FAIL' would occur when the CRJ-200 Main Cabin door was closed. Maintenance deferred both valves; but could not visually confirm the valve positions. Aircraft took off; but could not pressurize and an air turnback was performed. Captain alleges MEL procedure is inadequate.

Narrative

Aircraft had a problem when closing doors. An Amber 'OVBD COOL FAIL' and Status message. 'INBD COOL FAIL' would occur when the Main Cabin door was closed. Maintenance came out and deferred both valves. There were no major Operational items of interest in the MEL; unless a different option was used; which called for unpressurized flight below 10;000 feet. We Take-off and the aircraft does not pressurize so we elect to Return to the Field. Back at the gate in ZZZ; the Mechanic says that the valve Control switch was in the correct position; but there is no way to actually visually check the valve to ensure that it moved to the closed position. Either the Maintenance was preformed incorrectly or the procedure is inadequate; because the work cannot be confirmed; and therefore should not be allowed under an MEL program. Also; the aircraft had a Write up for the same issue in December that was Signed-off as corrected. We either have a faulty valve; or faulty Maintenance; or faulty Procedures.