Citationjet (C525/C526) - CJ I / II / III / IV
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 35; Flight Crew Total 3000; Flight Crew Type 50
Aircraft Equipment Problem Less Severe
Flight Crew Diverted; Flight Crew Landed As Precaution
Aircraft
Climbing through 13;000 feet MSL I observed a master warning and cabin altitude greater than 10;000 feet annunciator. I verified the annunciator with the cabin pressure indicator and it agreed with a high cabin pressure environment. I believe that the door; door seal; or the combination of the both of them may have contributed to the cabin pressurization issue. The door pins were all in place according to the door indicators and no door seal or cabin door unlock annunciators where displayed/observed.I had to divert to another airport as it would have been unsafe to continue our planned route.
CE-525 pilot reported diverting after observing a master warning and cabin altitude annunciator while climbing through 13;000 feet.