MODINE – Fan Delay Timer 24V The NBK-21055 Fan Delay Timer 24V provides precise control over blower fan operation in HVAC and greenhouse heating systems. By delaying fan startup and extending post-burn operation, it ensures the heat exchanger reaches optimal temperature before air circulation begins—enhancing energy efficiency and protecting system components from premature wear.Key Features:• Optimized Blower Operation: Delays fan start-up until the heat exchanger is warm, preventing cold air discharge• Energy Efficient: Keeps blower running briefly after burner shutdown to use remaining heat• OEM-Equivalent Performance: Matches factory specifications for smooth replacement and dependable operation• Compact 24V Design: Integrates seamlessly with most standard heating control circuitsSpecifications:• SKU: 21055• Category: HVAC / Fan Delay Timer• Description: NBK-21055 Fan Delay Timer 24V• Voltage: 24V• Equivalent To: – Modine 4034110 – Modine 5H0730350000 – 5H73035 – 5H71627 – 5H71627B – 3H32722 – 5H602054 – 5H602054-1Why Replace Your Fan Delay Timer:A worn or defective delay timer can cause inefficient heating, short cycling, or premature blower wear. Installing a new NBK-21055 restores proper timing, ensures warm air delivery, and improves both energy efficiency and comfort.








