Date: 201912
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: IMC
Weather elements / visibility: Icing
Aircraft: Regional Jet 900 (CRJ900)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class E ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Pneumatic Ducting
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Troubleshooting
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted
Contributing factors: Aircraft; Weather
Primary problem: Aircraft

Narrative: Mechanical diversion. While running the after takeoff check; we received an anti-ice bleed duct master warning. Takeoff was a bleeds open; wing and e/I on takeoff. Wings selected on roughly 30 seconds prior to takeoff clearance. PF (Pilot Flying) was the FO (First Officer); [and] I gave the radios to him to complete the Quick Reference Handbook. The wing valves ended up closing on their own; followed by the wing l and R anti-ice cautions as expected.Running the Quick Reference Handbook; the first step was to close the wing valve [and] then assure the warning goes out; which it did not. Message continued to persist. Checking the EICAS synoptic page showed a confirmed closed wing valve on both sides and a red line on the fuselage left-hand side. Putting [my] systems knowledge to work; I was fairly confident that this was a double failure of the fire loops on that section. We had no other indications at that time; smells; odors; hot spots in the cabin; or any other mechanical abnormalities.Continuing down the Quick Reference Handbook; [we] verified that we were not going to be in any icing. We were stuck at 15;000 in order to keep the TAT (Total Air Temperature) at 10 °C. We got PIREPs of negative ice tops between FL170 - FL220. We attempted to climb at Vmo. TAT dropped to 8 °C at FL190; followed shortly by an ICE light indication. I requested a descent back to 15;000. This was all while waiting for Dispatch; Maintenance Control; and the Duty Pilot as they were working with us over ACARS. We attempted a call over AIRINC but were too low.At this point; I suggested [to] divert. Although I had diagnosed this as a most likely fault; there is still the risk that bleed air [was] leaking in the belly. Dispatch suggested ZZZ; which had recover abilities and Maintenance. I was content after checking the weather and the routing kept us in reasonable proximity of ZZZ1 and ZZZ2 plus other central airports in the event we needed to land immediately.30 minutes out at the time of deciding; ATC was advised of the situation and did good in helping us out with information. They didn't understand SAT (Static Air Temperature) vs TAT and thought we were [in a] much worse of a situation. I advised them that we were fine; explained it to them and moved on. All of the nearby airports had a high layer cloud that would allow us to get down without icing concern. Going north on the flight planned route; we had a snow storm that was impacting the nearby areas and would have been unable to continue to that area without ice protection.I advised the flight attendants part way through that we were dealing with the mechanical [problem]. The forward Flight Attendant heard the aural and was patiently waiting. Once the diversion was for sure with a destination in mind; I advised the passengers. Mood was understandable and the fact that we had a plan in place already definitely helped. The Quick Reference Handbook definitely lacks guidance in the event the 'should' doesn't happen in this event. Presumed to be a malfunction of both loops of the dual loop system. Diverted to ZZZ.




Synopsis: CRJ-900 Captain reported receiving an anti-ice bleed duct warning; resulting in a diversion.