replacing the A-4000-613 at regular intervals is essential to protect high-sensitivity relay components and maintain precise calibration across the entire control branch

effectively breaking the electrical circuit to the gas valve or heating elements if the plenum temperature exceeds safe operating thresholds

is engineered to manage refrigerant flow with precision across varying load conditions

but shorter trials are generally safer for smaller combustion chambers

this specific model is a heat-only configuration with an "Off" position

Sporlan 108631 SBFV-A-C Expansion Valve Els PW 29614 replacing the A-4000-613 at regularThe Sporlan 108631 SBFV A C is a high performance balanced port expansion valve engineered for precision refrigerant metering in systems with fluctuating head pressures and varying loads. Designed specifically for R22, R407A, and R407C applications, this Type SBF valve features a durable brass bar body with 3 8" x 1 2" ODF solder connections and a 30 inch capillary tube. The balanced port construction ensures stable superheat control by neutralizing