Carrier 38QB900031 Electronic Timer

Carrier 38QB900031 Electronic Time Delay Relay is an OEM Carrier control module that provides a precise, built-in delay for HVAC circuits. The device accepts a 24 VAC control signal (24 V, 60 Hz) and can switch up to 5 A at 24 VAC, delivering a 5-minute recycle delay to sequence relays or contactors and help prevent short cycling in Carrier furnace and air‑handling equipment. This timer relay is intended for installation in Carrier HVAC control panels or downstream relay banks where a controlled interlock is required to coordinate start‑up sequences and protect components. Availability notes show that the 38QB900031 is listed as discontinued by the manufacturer, so stock can be limited and end users may explore stock from distributors or used parts. Key verified specifications include: part number 38QB900031; type Electronic Time Delay Relay; input voltage 24 VAC at 60 Hz; output rating 5 A at 24 VAC; delay characteristic of 5 minutes; and typical applications in Carrier heating, ventilation, and air‑handling equipment where timed relays govern relay coil energization or contactor operation. Typical installations include furnaces and air handlers where a timed interlock helps coordinate relay sequencing and protect equipment during startup and shutdown.