Carrier HH680610 Step Controller 320788-704 while the mechanical spring return

while the mechanical spring return closes the valve in less than 25 seconds upon power loss

Look for a constant audible hiss from the thermostat

utilizing standard 1/4" tab terminals for quick electrical integration

this motor vibration isolation kit utilizes high-durometer rubber grommets to decouple the motor from the blower housing

Durability: Engineered for high-temperature resilience in 90%+ AFUE furnace applications

Carrier HH680610 Step Controller 320788-704 while the mechanical spring returnThe Carrier HH680610 Step Controller is a critical Factory Authorized Part designed to manage the staging sequence in multi stage heating and cooling equipment. As a high precision HVAC step controller, it facilitates incremental capacity adjustments by activating small heating or cooling stages based on real time temperature fluctuations. This sophisticated modulation prevents system short cycling and optimizes energy consumption across multi stage