As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER INSTALLING A CABIN HEATER IN THE ACFT, WE HAVE HAD ISSUES WITH THE OPERATION OF THE HEATER. WE INSTALLED A NEW LINEAR RHEOSTAT CONTROL, PN CD21399 WHICH CAME WITH THE HEATER. OVER THE LAST FEW MONTHS WE HAVE HAD 3 FAILURES OF THE UNIT. IT APPEARS THAT THE CONTROL WORKS WHEN WARM BUT FAILS WHEN COLD. WE HAVE REPORTED THIS TO MFG AND HAVE ORDERED A ROTARY RHEOSTAT TO REPLACE THE UNIT.