TDX Series – Direct Vent

The TDX Series achieves its high efficiencies by re-circulating the flue gases through the boiler three times.  Most other residential boilers are designed for only one or two passes through the boilers.  With our three-pass design, the flue gases do not immediately exit through the chimney, but remain in the boiler longer for more efficient operation.

The TDX Series incorporates a specially designed water coil, which provides an abundant and equally efficient supply of domestic hot water.

  • FIRING RATE 0.90 to 1.25 GPH – Allows the installer to size the boiler more closely to the home heating needs for greater efficiency. The lowest firing rate, 0.90-95,000 BTU, is necessary for many well insulated homes where the heat loss is minimal.
  • PUMP PRESSURE – The TDX-Series operates at 140 PSI pump pressure for better fuel atomization, thereby having the ability to tolerate fuel oil with heavy ends.
  • IGNITION SYSTEM – The TDX-Series is standard with a state-of-the-art, solid state ignition system, making it more tolerant to low voltage or voltage fluctuations.
  • ELECTRONIC DELAY with Solenoid Valve “clean-cut” Fuel Pump
  • WATER CONTENT – 29.3 gallons

  • EFFICIENCIES UP TO 87% AFUE – The unique tube design of the S-Series boiler heat exchanger slows the flue gases, allowing for more effective heat transfer without the need for extreme baffling often seen in other vertical tube boilers.
  • STANDARD FEATURES- The following built-in features found in all Thermo-Dynamics boilers increase the longevity of the boiler and make the unit easier to service, ensuring maximum efficiency and performance for the life of the boiler.
  • BUILT-IN “AIR SCOOP” – purges air from the system providing a quiet, trouble free hot water heating system without the use of external devices.
  • EXTENDED FLANGE COIL – is away from the boiler for easy accessibility. The use of ribbed neck carriage bolts eliminates the problems encountered when a weld stud is broken during servicing. The large coil plate allows for a greater gasket sealing area.
  • EASY CLEANING – and maintenance accessibility to combustion areas and the open tubes make it easy for the service technician to thoroughly clean the boiler. No tight, pin-type passage ways with “hidden nooks and crannies”, making a thorough cleaning impossible. A well-maintained boiler continues to perform at higher efficiency and is less likely to develop service problems.

Standard Features

  • EFFICIENT, SENSIBLE AND DEPENDABLE – High efficiency of 87%, recirculating triple pass design and includes an advanced boiler control for increased operating efficiency and low water cut-off
  • EFFICIENT – Achieves its high efficiencies by re-circulating the flue gases through the boiler three times. With our three-pass design the flue gases do not immediately exit through the chimney, but remain in the boiler longer for more efficient operation.
  • VENTING – The TDX can be vented by either a standard chimney or direct-vent with an optional DV kit. Such application would be ideal for new home without a chimney, older homes with chimneys not up to code or electric to oil conversions.
  • Serviceability – designed with a heating professional in mind. A unique front jacket panel designed for easy removal allows convenient access to a one piece, swing out door.

Picture – Drawing

ASME Code BoilerStriking Two-Tone Cabinetry
Altitude, Temperature & Pressure GaugeASME Relief Valve
Built-In "Air Scoop"Factory Assembled, Wired & Packaged
National Board StampedReversible Full Swing Door
No Combustion Chamber DesignBurner Quick Disconnect
Aquasmart Control or Hydrolevel Control


Firing Rate GPH0.901.001.101.25
Input BTU/HR126,000140,000154,000175,000
DOE Capacity BTU/HR110,000121,000132,000148,000
Net Output BTU/HR95,000105,000115,000129,000
DOE Efficiency87.0%86.5%86.0%85.5%
Boiler Tubes8888
Water Content - Gallons28282828
Supply1 ¼"1 ¼"1 ¼"1 ¼"
Return1 ¼"1 ¼"1 ¼"1 ¼"
Coil Capacity5 gal5 gal5 gal5 gal
Shipping Weight Lbs.460460460460

Vent Kits

THERMO-VENT 175 Vent Kits
One per boiler required.
One wall opening required.
Part No.Shipping Weight (pounds)
TV-175 Combination Vent Kit - 10ft28107224
TV-175 Combination Vent Kit - 15ft28108230
TV-175 Combination Vent Kit - 20ft28109336
* Note: Vent Hood Packaged Separately from Tubing. (2-cartons) 4" tubing shipped inside of 5" tubing.

DIRECT VENTING KITS – 10ft., 15ft., 20ft. Includes:

1 – Sized Length of 5″ Stainless Steel Flexible Vent Tubing
1 – Stainless Steel Combination Air Intake Exhaust Vent Hood
1 – 5″ Stainless Steel Flex Tubing Connector
1 – 4″ Tee w/Vacuum Relief
1 – Sized Length of 4″ Aluminum Flexible Intake Tubing
Attaching Screws, Silicon Sealer, Instruction Sheet
Note: Connector Tubing standard NFPA 9″ Clearance to Combustible.

TDX Series – Manual

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Boiler Warranty

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