Flight Crew Air Transport Pilot (ATP)
Troubleshooting
Aircraft Equipment Problem Less Severe
Air Traffic Control Provided Assistance; Flight Crew Diverted
Aircraft
Passing through FL220; we received a L duct warning message. I leveled off the aircraft and called for the checklist. Within 15 seconds of the warning both packs had shut down. While the other pilot was doing the checklist I advised ATC that we needed to descend to 10000 ft. After completing the checklist; the non-flying pilot notified the flight attendants of the situation and then notified company. After getting everything accomplished we decided to divert to [a suitable airport]. We then notified the company of our plan; then ATC in addition to the passengers. We had a non-eventful landing.
[Report narrative contained no additional information.]
CRJ900 flight crew reported experiencing pressurization issues.