Be-200 first officer reported loss of pressurization inflight.

Attributes
ACN	1629738
Time
Date	201903
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Super King Air 200
Operating Under FAR Part	Part 135
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	Pressurization System
Person 1
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor
Experience	Flight Crew Last 90 Days 150 Flight Crew Total 14000 Flight Crew Type 1600
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy Deviation - Procedural Clearance

Narrative:

We departed for a flight with 2 passengers. We had the cabin mode controller in manual cool since it seems to cool down better in this mode. We were cleared to flight level 220 and as we climbing through about 17;000; I tried to warm the cabin some by holding the increase temp switch. It didn't seem to be warming much so I switched to manual warm. When I did we lost all bleed air coming into the cabin and the cabin altitude started climbing. I attempted to re-select manual heat and nothing happened. I tried auto mode and still nothing happened. At this point the cabin altitude was approaching 8;000+. We don oxygen masks and [notified ATC]. We were immediately cleared to 10;000 feet. We ran the checklist and were asked where we would like to divert to. I asked for ZZZ which we were then cleared to. We did not try to re-pressurize the cabin. We made a slow descent into ZZZ.

Original NASA ASRS Text

Title: BE-200 First Officer reported loss of pressurization inflight.

Narrative: We departed for a flight with 2 passengers. We had the cabin mode controller in manual cool since it seems to cool down better in this mode. We were cleared to flight level 220 and as we climbing through about 17;000; I tried to warm the cabin some by holding the increase temp switch. It didn't seem to be warming much so I switched to manual warm. When I did we lost all bleed air coming into the cabin and the cabin altitude started climbing. I attempted to re-select manual heat and nothing happened. I tried auto mode and still nothing happened. At this point the cabin altitude was approaching 8;000+. We don oxygen masks and [notified ATC]. We were immediately cleared to 10;000 feet. We ran the checklist and were asked where we would like to divert to. I asked for ZZZ which we were then cleared to. We did not try to re-pressurize the cabin. We made a slow descent into ZZZ.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.