As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
OWNER COMPLAINED OF NO HEAT IN CABIN AND CONTROL FROZEN. FOUND FLAPPER VALVE PN NR 04530181 BROKEN AT LT SIDE HINGE NOT ALLOWING DOOR TO OPEN AND CONTROL SHAFT GO OVER CENTER. REMOVED CABIN HEAT BOX AND REPLACED VALVE AND REASSEMBLED. OPS CHECKED OK. PART REPLACED UNDER MFG WARRANTY.