Regional Jet 900 (CRJ900)
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; General Flight Cancelled / Delayed
Aircraft
During the climb out we experienced a L BLEED DUCT warning message. The First Officer was the Pilot Flying. He remained on the controls and radios while I ran the appropriate checklists and made the necessary communications to the crew; the passengers; and the company. [We advised ATC] and we were given priority handling back to land at ZZZ. The temperature in both the cabin and the cockpit reached 40 degrees Celsius because we were unable to maintain an open engine bleed valve. The warning occurred at approximately 12;000 feet MSL. We immediately got a clearance to descend below 10;000 feet MSL as pressurization could not be maintained. We then only had ram air to cool the cockpit and cabin. We landed safely on runway and taxied directly to gate where the passengers were deplaned through the normal method.
CRJ-900 Captain reported a loss of cabin pressure and inability to control cabin temperature; resulting in an air turn back.