Modine HD125 Hot Dawg Heater

Hot Dawg HD125 125,000 BTU Gas-Fired Unit Heater

The Modine HD125 Hot Dawg is a 125,000 BTU gas-fired unit heater available in power-vented and separated-combustion configurations, in stock and ready to ship. Not sure which HD125 model fits your space? Call us to verify before you order.

Series	Type	Fuel Options
HD125, HDB125	Power-vented (propeller fan / centrifugal blower)	Natural gas, propane
HDS125, HDC125	Separated combustion (propeller fan / configurable blower)	Natural gas, propane

The HD125 uses the same burner for natural gas and propane. Field conversion kits are available if you need to switch fuel types after installation. All HD125 models are certified for residential and commercial use and approved in California and Massachusetts.

Warranty claims and returns on parts purchased from Heinlein Supply are processed directly through Heinlein Supply, your authorized Modine distributor.

Call now for an accurate price quote and estimated delivery time.

773-774-8616

HD125 Venting and Installation

All HD125 and HDS125 models use 4-inch vent pipe. The power-vented HD125 supports vertical Category I or horizontal Category III venting with a total equivalent length of 3 to 30 feet. The separated-combustion HDS125 uses two-pipe or concentric venting with a total equivalent length of 3 to 25 feet. The vent terminal part number for the 100 to 125 size range is 5H0722850001.

Clearance to combustibles for the HD125 (propeller fan) is 1 inch at top, bottom, access side, and non-access side, 18 inches at the rear, and 4 inches at the vent connector. The HDB125 (centrifugal blower) requires 6 inches at top, bottom, access, and non-access sides, with the same 18-inch rear and 4-inch vent connector clearances. HDS125 clearances match the HD125, while HDC125 follows the HDB125 pattern.

HD125 Gas and Controls

Inlet gas pressure should be 6 to 7 inches W.C. for natural gas and 12 to 14 inches W.C. for propane. Maximum gas pressure to appliance controls is 14 inches W.C. The HD series uses direct spark ignition. All replacement wiring must be rated for at least 105°C, and any replacement parts must be factory-approved Modine components ordered by model and serial number.

HD125 FAQ

Can I convert the HD125 from natural gas to propane in the field?

Yes. The HD125 uses the same burner for both fuels. A field conversion kit is available for switching between natural gas and propane after installation.

What vent size does the HD125 require?

The HD125 and HDS125 both use 4-inch vent pipe. Maximum equivalent vent length is 30 feet for power-vented models and 25 feet for separated-combustion models.

Is the HD125 approved for residential garages?

Yes. The HD125 is certified for both residential and commercial applications, including garage installations. It is also approved for use in California and Massachusetts.

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