Diversitech SEQHDR221 Heat Sequencer Dpst-spst 3 Switches

Product Description

The DIVERSITECH SEQHDR221 is a heat sequencing control designed for ducted electric heating systems that require three staged heating circuits. It combines DPST normally open and SPST normally open contacts operated by a single timing element to deliver controlled heat staging. The delay on timing runs 1 to 25 seconds, while the delay off timing extends from 50 to 110 seconds. This adjustable staging window prevents simultaneous element energization, reducing demand spikes and protecting the electrical system. Licensed HVAC technicians install this sequencer as part of electric furnace or air handler servicing.

This sequencer is suited for residential and light commercial ducted electric heating applications where multiple heating elements must be staged on and off in sequence. Systems with three heating circuits benefit from the combined DPST and SPST switch configuration, which allows one timing element to control all three switch contacts. It is a direct replacement-style control for electric furnaces and electric air handlers that use a single-element sequencer with three output switches.

Key Features

• Single timing element controls three switch contacts: one DPST normally open and one SPST normally open
• Delay on range of 1 to 25 seconds staggers element startup and reduces electrical demand spikes
• Delay off range of 50 to 110 seconds extends residual heat dissipation after the call for heat ends
• Three-switch configuration supports staged control of up to three heating circuits
• Designed for ducted electric heating systems in residential and light commercial applications

Compatibility

Designed as an OEM-style replacement for ducted electric furnaces and electric air handlers that require a single-timing-element heat sequencer with three switching contacts in a DPST-SPST configuration.

Installation Notes

A licensed HVAC technician should install or replace this sequencer. Disconnect all electrical power to the air handler or electric furnace at the disconnect and breaker panel before beginning work. Verify the system voltage and amperage ratings are within the sequencer specifications before energizing. Installation should conform to applicable local electrical codes and NEC requirements for electric heating equipment.

Technical Specifications

• Switch Configuration: DPST normally open and SPST normally open
• Number of Switches: 3
• Timing Elements: 1
• Delay On: 1 to 25 seconds
• Delay Off: 50 to 110 seconds

Standard Information

• Brand: DIVERSITECH
• Manufacturer Part Number: SEQHDR221