Aprilaire 4851 Relay 320788-704 or individual 7-day schedules to

or individual 7-day schedules to match specific user demand patterns

2" WC setpoints for precise air pressure monitoring

Optimized Ignition: Reaches operating temperature quickly to ensure reliable furnace burner ignition and prevent delayed ignition codes

preventing "nuisance" cycling of dangerous conditions

or the AC system's inability to maintain setpoint temperatures despite proper airflow

Aprilaire 4851 Relay 320788-704 or individual 7-day schedules toThe Aprilaire 4851 Relay is a high performance Blower Activation Relay engineered specifically for seamless integration with whole house humidification and HVAC systems. This critical component allows your HVAC control board to initiate the furnace blower independently of a heat call, ensuring optimal humidity distribution throughout the living space. Designed as a direct Aprilaire replacement part, it facilitates the necessary electrical handshake