it is critical to verify the specific burner assembly specs

Optimized System Logic: Restores factory-calibrated timing for compressor delay and fan relay operations

is not interchangeable with Mark IV or MicroTech II legacy boards due to different terminal layouts and communication protocols

This model provides positive dead-end lockup

Resideo THP9045A1023 Wire Saver 322027-701 it is critical to verifyThe Resideo THP9045A1023 Wire Saver is a specialized C wire adapter designed for 1 heat 1 cool retrofit applications where the existing thermostat cable lacks a dedicated 24V common wire. By utilizing the K terminal on compatible Honeywell Home thermostats, including the RedLINK 8000 series and THX9000 Series, this module effectively splits the signal at the air handler or furnace. This allows a single conductor to manage both fan and compressor relay