Modine HDC Separated Combustion

Modine HDC Separated Combustion


$3,755.00 Regular price
  • Ships directly from manufacturer - departs in 6-10 weeks

Modine's HDC series features a blower type fan for increased air flow performance over traditional propeller units in a separated combustion configuration. The higher CFM ratings of these units make them a perfect solution for warehouses, large garages or workshops where heat needs to be thrown a long distance while drawing combustion air from the outside for dusty or humid applications.

Standard Features

  • Less maintenance in dusty environments.
  • Improved efficiency by using outside air for combustion.
  • Greater durability in "hostile" environments (environments possessing substances that may deteriorate the performance of the unit).
  • External thermostat and gas connections.
  • Hush-puppy quiet operation.
  • Uses natural or propane gas.
  • Certified for residential, commercial and industrial use.
  • Low-profile design and neutral color to blend in with decor.
  • Lightweight, easily installs 1" from ceiling with only 2 angle brackets (included).
  • Install quickly and easily with field wiring connections and knockouts for quick access to gas and electricity.
  • Standard power exhaust simplifies side-wall or roof venting with small-diameter vent pipe.
  • Versatile design allows for right or left hand controls and installation. Gas, electrical and flue connections can be changed from one side to the other by simply flipping the Hot Dawg over.
  • Permanently-lubricated motor for trouble-gree dependability.
  • Full 10-year warranty on heat exchanger.


  • 100% Outside Air for Combustion
  • Sealed Compartment Protects Combination Gas Control
  • Ignition Control
  • Manifold and Burner
  • Horizontal or Vertical Concentric Venting
  • 80% Thermal Efficiency
  • Field Convertible to Propane
  • 100% Shut-Off with Continuous Retry

Dimensions and Diagrams

Dimensions, Diagrams, and Specifications (Page 4 shows HDC model.)

Modine Greenhouse Heating Solutions (PDF)

Wiring Diagrams (PDF)

Performance Specifications

Item NO. Input Output BTUH Vent Size Motor HP Airflow CFM Range Air Temp Rise Range
HDC60 60,000 48,000 4" 1/4 635 - 1100 40-70
HDC75 75,000 60,000 4" 1/3 795 - 1390 40-70
HDC100 100,000 80,000 4" 1/2 1060 - 1850 40-70
HDC125 125,000 100,000 4" 1/2 1240 - 2050 45-75

*Do not locate any gas-fired unit in areas with chlorinated, halogenated or acidic vapors in atmosphere.


Many of our customers happily report that purchasing a Hot Dawg heater from the Greenhouse Megastore helped them save 50% or more off the unit price received from a local HVAC installer. However, for safety reasons and to minimize installation problems Modine strongly recommends having a licensed HVAC technician install your Hot Dawg heater. Although we are happy to offer limited technical support for your Hot Dawg purchase, we can NOT install the heater for you over the phone nor are we able to troubleshoot problems you may experience if you choose to install the heater yourself. By purchasing this heater from us, you accept sole responsibility for installation and agree to abide by Modine's limited Warranty.

Comparison Chart

Modine HD-Series vs. Sterling RF-Series

Specification Modine HD-Series Sterling RF-Series Comments
BTU Range 30 - 125 MBH 30 - 90 MBH Modine covers more applications
Minimum Efficiency 80% 80% Same non-condensing high efficiency
Blower Fan Units
(HDB model only)
60 - 125 MBH Not Available Modine covers more applications
Casing Paint Polyester Powder Wet Enamel Modine units will look better longer
Quiet Swept Wing Fans 100 and 125 MBH Not Available Larger Modine units are quieter
Heat Exchanger Gauge 18 Gauge 20 Gauge Modine heat exchangers are heavier gauge
Optional Stainless Steel Yes Not Available Modine covers more applications for corrosive environments
T.E. Fan Motor Standard Yes No Modine motors are protected for longer life
Power Vented X-Changer Warranty
(HDS and HDC models only)
10 Years 10 Years Same 10 year heat exchanger warranty
Sep. Comb. X Changer Warranty
(HDS & HDC models only
10 Years 5 Years Modine separated combustion units warrantied longer
Component Warranty 2 Years 1 Year Modine parts warrantied longer

Additional Information


Residential Owners Manual (PDF)


Modine offers a 10 year limited warranty on the heat exchanger and a 2 year limited warranty on all other components. Please note this warranty covers parts only and does not cover any labor costs associated with repairing the heater. View Warranty (PDF)

Product Video

Heater Warranty and Return Policy

It is the customer's responsibility to carefully inspect heaters for damage before accepting delivery since heaters are usually not returnable once delivery is accepted. Obviously damaged heaters should be refused and Greenhouse Megastore customer service contacted to make arrangements for a replacement unit. Once delivery is accepted Greenhouse Megastore will gladly provide replacement parts under the manufacturer's warranty to repair damaged or defective heaters; however this warranty does not include any labor costs associated with installing these parts. Warranty issues should be diagnosed by a certified HVAC technician since parts deemed not to be defective by the manufacturer are not available for credit back to the customer. Specific warranty policies vary by manufacturer but typically cover replacement parts as indicated above up to one year after purchase. Please contact Greenhouse Megastore customer service if you have any questions about the warranty for your specific heater.

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