Q105 Furnace Heat Pump Sequencer 24 Volt

Product Description

The Q105 is a furnace and heat pump sequencer designed to control the staged operation of heating elements and blower motors in residential and light commercial heating systems. Operating on a 24-volt control circuit, it features a 1DPST and 1SPST contact arrangement with adjustable on and off timing of 1 to 110 seconds. Contacts M1-M2 energize first and de-energize last, establishing the primary stage sequence. A built-in five-second delay separates all subsequent stages, preventing simultaneous inrush loads. This part is installed by licensed HVAC technicians during system repair or component replacement.

The Q105 sequencer is suited for use in electric furnaces, heat pump systems, gas furnaces, and oil furnaces. It manages the sequenced activation of resistance heating elements and blower motors, protecting electrical components from simultaneous startup loads. Alternate part numbers associated with this sequencer include 3120A357, 525-37327-000, ZC24A34-5, IES24A34-5, 24A35-5, 24A34-54, 51172-32, 33232, 33832, and NS105, which may aid in cross-referencing during procurement or replacement.

Key Features

• 24-volt control circuit compatible with standard low-voltage thermostat wiring
• Adjustable on-delay of 1 to 110 seconds and off-delay of 1 to 110 seconds
• 1DPST and 1SPST contact configuration for multi-stage load control
• Contacts M1-M2 activate first and deactivate last, defining primary stage priority
• Five-second inter-stage delay prevents simultaneous inrush across subsequent stages
• Compatible with electric, gas, oil, and heat pump furnace applications

Compatibility

This sequencer is a replacement part compatible with major brands of electric furnaces, heat pump systems, gas furnaces, and oil furnaces. Always verify fitment against the specific model number of the equipment being serviced. Alternate compatible part numbers include 3120A357, 525-37327-000, ZC24A34-5, IES24A34-5, 24A35-5, 24A34-54, 51172-32, 33232, 33832, and NS105.

Installation Notes

Installation of a heating sequencer should be performed by a qualified HVAC technician. Disconnect all electrical power and, where applicable, shut off the gas supply to the unit before beginning any service work. Sequencers are wired into the low-voltage and line-voltage control circuits, so confirm all connections are secure and insulated before restoring power. Follow applicable local codes and manufacturer wiring diagrams during installation.