Goodman-Amana 20KW Heat Sequencer, B1256554/B12565-54/309564

B12565-54 (or B1256554) is a Goodman/Amana furnace heat sequencer, a crucial HVAC component that controls the staggered activation of electric heating elements (usually up to four) in an electric furnace, ensuring efficient, safe, and comfortable heating by managing stages and protecting the blower motor. It's a common replacement part for many Goodman, Amana, and Janitrol air handlers and electric furnaces, often found in models like AE60-20, A36-20, and A42-20, and it manages both low-voltage (24V) control and higher-voltage (240V) heating circuits. 

Key Functions & Features:

• Multi-Stage Control: Manages the sequence of multiple heating elements for precise temperature control.
• Energy Efficiency: Optimizes energy use by activating elements as needed.
• Blower Delay: Keeps the blower fan running briefly after elements shut off to cool them down.
• Compatibility: Replaces various other brands (Coleman, York, Carrier) and works with many Goodman/Amana models.
• Voltage: Operates with a 24V coil but switches higher voltage circuits (120-240V) for heating elements. 

Electrical Specifications Voltage Ratings:

• Control Circuit (Coil): 24 VAC (Volts AC). These connect to the bottom terminals.
• Main Power Circuit (Switches): 240 VAC. These connect to the top and middle terminals.
• Wattage (Power Handling): The sequencer is rated for use in systems up to 20 kW (kilowatts).
• Switches: It features four switches (or sets of contacts) to manage multiple heating elements in sequence.
• Timing:
• "On" (Activation) Time Delay: 1 to 110 seconds.
• "Off" (Deactivation/Cool-down) Time Delay: 1 to 110 seconds. 

Affiliated and Cross-Referenced Part Numbers:

• B12565-54: This is a common way the part number is written or appears on the physical component.
• 241T78: An internal or distributor stock number used by Grainger.
• 586771: The internal part number used by GoodmanParts.net for cataloging.
• HK20 and HK20-1: While these are heat kit assembly numbers, the B1256554 sequencer is the core component within them.

Here are some specific model numbers compatible with the B1256554 heat sequencer:

A Series Air Handlers:

• A36-20
• A42-20
• A48-20
• A49-20
• A60-20
• A61-20

AE Series Air Handlers:

• AE60-20 (also listed as AE60-20A)
• AV Series Air Handlers:
• AV36-60-20

Heat Kits:

• HK20 (This is the 20kW heat kit assembly itself, compatible with the sequencer)
• HK15-1 (Also listed as compatible by some suppliers, though the B1256553 is more common for 15kW)