Carrier HK28ZT001 Control R 410A the 043337 is designed to the 043337 is designed to handle the higher pressures of R 410A while maintaining compatibility with R 22 and other HFC or HCFC refrigerants using mineral or POE oils oil filled metal housing for efficient heat dissipation and internal pressure sensitive interrupter safety The HK28ZT001 module supports multiple operating voltages and features a high impedance fan shutdown line that pulls to ground when smoke is detected this wired control unit continuously analyzes air samples through a photoelectric smoke sensor interface to trigger immediate unit shutdown during an alarm event