TQ vs TQR – Key Technical Differences and model comparisons September 2025


12-page Pdf attached - showing key technical differences 

Overview

Seeley International’s TQR series represents a significant upgrade over the TQ series, focusing on improved performance, easier servicing, and flexible installation. This guide outlines the key differences and includes model equivalency and support resources.

Key Design Improvements

1. Redesigned Heat Exchanger

  • Dimpled tubing improves heat transfer and system efficiency.
  • Fewer joints reduce air leaks and back pressure.
  • Enhanced reliability and performance

2. Simplified Combustion Fan System

  • New bolt-in fan design with just three screws—no locking tabs.
  • Two fan models cover all TQR units:
    • One for single and 2-stage heaters
    • One for modulating heaters
  • Mounted on a cast aluminium flu pan for durability and service access
  • Watch video on rotating combustion fan

3. Enhanced Burner Rail Design

  • Tougher build for field conditions.
  • Front and rear access simplifies cleaning and diagnostics.
  • Improved visibility of spark and flame sensors
  • Watch video on accessing burner rail

Safety Component Relocation

OT1 (Over-Temp 1 Sensor)

  • Now mounted on an adjustable bracket at the air outlet.
  • Ensures consistent operation across varied duct setups.
  • Must be repositioned if outlet configuration is changed from factory.
  • Watch video on duct exit configuration and relocating OT

Flame Rollout Sensor

  • Relocated to a central burner location forimproved safety and accessibility

Component Variations

Combustion Fan Resistor

  • Resistance values differ between TQR and TQ models.
  • Always check the TQR parts list before ordering replacements.

Pressure Switches

  • TQR models may use different pressure switches than TQ models.
  • Identified by blue and orange labels.
  • Check the TQR parts list to ensure correct switch selection.

TQR vs TQ Comparison Chart – (September 2025)
- TQR3 ↔ BMQ3 & TQ3
- TQR4 ↔ TQ4
- TQR5 ↔ TQM5


TQR3 + BMQ3 vs TQ3 - Comparisons

Model

kW Output

Gas rate (MJ/h)

Airflow (l/s @100Pa)

Duct Diameter (mm)

TQR316

16

72

570

300

TQR321

21

90

695

300

TQR328

28

126

770

350

 

 

 

 

 

TQ315

14

60

475

300

BMQ315

14

60

475

300

TQ320

18

80

630

300

BMQ320

18

80

630

300

TQ325

23

100

755

350

TQ330

28

122

960

350

BMQ330

28

122

960

350



TQR4 vs TQ4 - Comparisons

Model

kW Output

Gas Rate (MJ/h)

Airflow (l/s @100Pa)

Duct Diameter (mm)

TQR416

16

72

570

300

TQR421

21

90

695

300

TQR428

28

126

770

350

 

 

 

 

 

TQ415

14

60

475

300

TQ420

18

80

630

300

TQ4X20

18

80

695

350

TQ425

23

100

755

350

TQ4X25

23

100

810

350

TQ430

28

122

960

350

TQ435

32

140

1050

400



TQR5 vs TQM5 - Comparisons

Model

kW Output

Gas Rate (MJ/h)

Airflow (l/s @100Pa)

Duct Diameter (mm)

TQR521

21

90

695

300

TQR521U (ULPG)

21

90

695

300

TQR528

28

126

770

350

TQR528U (ULPG)

28

126

770

350

 

 

 

 

 

TQM520

20

88

630

300

TQM5X20

20

88

695

350

TQM5X20U (ULPG)

20

88

695

350

TQM530

28

122

960

350

TQM5X30

28

122

1050

400

TQM5X30U (ULPG)

28

122

1050

400


Additional Resources

Links to some helpful YouTube videos that demonstrate some key improvements


CLICK TO VIEW - YouTube Video Key differences TQR 2025 versus TQ heaters


CLICK TO VIEW - TQR Duct Exit Configuration YouTube Video


CLICK TO VIEW - YouTube Video TQR Burner Access

 

Link to TQR installation manual


CLICK TO VIEW - TQR3, TQR4, TQR5 & TQR6 installation manual gas ducted heater