Flagro FVO-400 – 390,000 BTU Indirect Fired Heater
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The Flagro FVO-400 390,000 BTU Oil-Fired Indirect Heater delivers dependable temporary heating for construction sites, warehouses, industrial facilities, and commercial applications. Featuring a built-in fuel tank, stainless steel heat exchanger, and portable construction, it provides high-capacity heat with flexible air distribution.
Key Specifications:
- Heating: 390,000 BTU/hr
- Fuel: Diesel, Fuel Oil or Kerosene
- Airflow: 2,500 CFM
- Fuel Tank: 42 Gallons
- Runtime: Approximately 14 Hours
- Electrical: 115V / 15A Supply
- Ducting: Up to 50 Feet
- Weight: 450 lbs
Features: Riello burner, dual 12″ outlets, flat-free wheels, and optional Tigerloop fuel system.
Nationwide shipping available. Contact us for pricing and availability.
The Flagro FVO-400 390,000 BTU Oil-Fired Indirect Heater provides reliable temporary heating for construction sites, warehouses, industrial facilities, commercial buildings, and temporary structures. Designed for demanding environments, this portable indirect-fired heater delivers 390,000 BTU/hr of heating capacity and 2,500 CFM of airflow.
Featuring a built-in 42-gallon fuel tank, the FVO-400 offers approximately 14 hours of manufacturer-published runtime, making it a practical choice for temporary heating projects where portability and dependable performance are essential.
The heater utilizes proven Riello burner technology and a fully welded 16-gauge 304 stainless steel heat exchanger to separate normal combustion exhaust from the heated supply air.
Its compact cabinet, heavy-duty flat-free wheels, and built-in fuel storage allow contractors to transport and position the heater at suitable jobsites.
With dual 12-inch heated-air outlets, optional alternative outlet configurations, and support for approved ducting up to 50 feet, the Flagro FVO-400 delivers flexible heating for temporary commercial and industrial applications.
Key Features of the Flagro FVO-400
- 390,000 BTU/hr Heating Capacity: High-output temporary heating for commercial and industrial spaces.
- 2,500 CFM Airflow: Provides substantial heated airflow for construction and temporary HVAC applications.
- Indirect-Fired Heating: Separates normal combustion exhaust from heated supply air.
- 42-Gallon Fuel Tank: Integrated onboard fuel storage for convenient operation.
- Approximately 14-Hour Runtime: Manufacturer-published operating duration under specified conditions.
- Riello Burner Technology: Features a nozzle preheater and updated low-temperature fuel pump for cold-weather operation.
- 304 Stainless Steel Heat Exchanger: Fully welded, 16-gauge construction.
- 115V Electrical Operation: Requires compatible 115V electrical service with a manufacturer-listed 15-amp supply.
- 3/4 HP Blower Motor: Delivers 2,500 CFM of airflow.
- Direct Spark Ignition: Provides automatic burner ignition.
- Dual 12-Inch Outlets: Standard configuration for heated-air distribution.
- Alternative Single 16-Inch Outlet: Available for compatible air-distribution arrangements.
- Up to 50 Feet of Ducting: Supports approved extended heated-air installations.
- Flat-Free Wheels: Two 16-inch wheels for jobsite mobility.
- Smart Power Indicator: Helps verify proper electrical supply.
- Optional Tigerloop System: Available to help prevent fuel-system air locks.
- cETLus Listed: Manufacturer-listed safety certification.
Indirect-Fired Heating for Commercial Applications
The Flagro FVO-400 uses indirect-fired heating technology to deliver warm air without intentionally introducing burner combustion products into the conditioned airflow.
Unlike direct-fired heaters, which discharge combustion gases into the heated-air stream, an indirect-fired heater transfers heat through a separate heat exchanger.
The FVO-400 features a fully welded 16-gauge 304 stainless steel heat exchanger, providing separation between combustion exhaust and heated supply air during normal operation.
This design is useful for applications where direct-fired combustion products and added combustion moisture are undesirable.
Advantages of Indirect-Fired Heating
- Heated supply air is separated from normal combustion exhaust.
- Combustion moisture is not intentionally introduced into the conditioned air.
- Heated air can be distributed through compatible ducting.
- Suitable for properly designed temporary commercial heating systems.
- High-capacity heating without permanent HVAC installation.
Important: Combustion exhaust must still be safely discharged outdoors, and adequate combustion air, ventilation, and equipment clearances are required.
Common Applications for the Flagro FVO-400
Construction Site Heating
Construction projects frequently require temporary heating during winter operations, building renovations, and HVAC installation.
The FVO-400 provides 390,000 BTU/hr of heating for appropriately sized construction environments.
Common applications include:
- Commercial construction projects
- Temporary winter heating
- Building renovations
- Construction enclosures
- Equipment maintenance areas
- Temporary heating during HVAC installation
Its built-in fuel tank and flat-free wheels help simplify movement and setup between suitable work areas.
Warehouses and Industrial Facilities
Warehouses and manufacturing facilities may require supplemental heating during extreme temperatures, equipment maintenance, or permanent HVAC failures.
The FVO-400 provides a portable heating option for appropriately designed temporary industrial applications.
Compatible heated-air ducting can help direct warm air into selected work areas.
Temporary Structures and Commercial Tents
The Flagro FVO-400 can support properly engineered heating installations for temporary structures and commercial tents.
Its indirect-fired design keeps normal burner exhaust separate from the heated supply air.
Heater placement, combustion exhaust, ventilation, duct routing, and fire-safety requirements must be evaluated before installation.
Emergency Commercial Heating
The FVO-400 can provide temporary heat during:
- Unexpected HVAC failures
- Planned heating-system shutdowns
- Commercial building renovations
- Winter construction projects
- Industrial maintenance
- Temporary facility operations
Explore Commercial Heating Applications
Flagro FVO-400 Technical Specifications
| Specification | Flagro FVO-400 |
|---|---|
| Model Number | FVO-400 |
| Equipment Type | Oil-Fired Indirect Heater |
| Heating Capacity | 390,000 BTU/hr |
| Fuel | No. 1 / No. 2 Fuel Oil, Diesel or Kerosene |
| Fuel Tank Capacity | 42 US Gallons |
| Published Runtime | Approximately 14 Hours |
| Published Fuel Consumption | Approximately 2.75 GPH |
| Electrical Supply | 115V / 60Hz |
| Manufacturer-Listed Supply | 15 Amps |
| Operating Current | 10.5 Amps |
| Fan Motor | 3/4 HP |
| Airflow | 2,500 CFM |
| Burner | Riello |
| Ignition | Direct Spark |
| Burner Nozzle | 2.00 × 60B |
| Fuel Pump Pressure | 170 PSI |
| Heat Exchanger | 16-Gauge 304 Stainless Steel |
| Standard Air Outlets | Two 12″ Diameter |
| Alternative Air Outlet | One 16″ Diameter |
| Published Ducting Capability | Up to 50 Feet |
| Return-Air Recirculation | No |
| Smart Power Indicator | Yes |
| Wheels | Two 16″ Flat-Free |
| Length | 70″ |
| Width | 29″ |
| Height | 52″ |
| Weight | 450 lbs |
| Optional Fuel System | Tigerloop |
| Certification | cETLus |
Specifications reflect Flagro’s published FVO-400 product listing and technical literature. Confirm current electrical, fuel, exhaust, and ducting requirements against the supplied equipment nameplate and operating manual.
42-Gallon Fuel Tank and Runtime
The Flagro FVO-400 features a built-in 42-gallon fuel tank.
This allows the heater to operate without requiring a separate external fuel tank for standard applications.
Fuel Specifications
| Specification | Value |
|---|---|
| Tank Capacity | 42 US Gallons |
| Published Runtime | Approximately 14 Hours |
| Fuel Consumption | Approximately 2.75 GPH |
| Approved Fuel Types | No. 1 / No. 2 Fuel Oil, Diesel or Kerosene |
Actual runtime depends on available fuel, burner configuration, and operating conditions.
The manufacturer identifies approximately 14 hours of operation under its published rating conditions.
Benefits of Integrated Fuel Storage
- Reduces the need for separate fuel storage equipment
- Simplifies temporary heating installations
- Allows the heater to be repositioned more conveniently
- Supports extended operation between refueling stops
Fuel storage, filling, and operation must follow Flagro’s instructions and applicable regulations.
Electrical Requirements
The Flagro FVO-400 operates on 115V electrical power.
Published electrical specifications include:
- Power Supply: 115V
- Manufacturer-Listed Supply: 15 Amps
- Operating Current: 10.5 Amps
- Fan Motor: 3/4 HP
- Smart Power Indicator: Included
The heater requires a compatible grounded electrical supply.
Confirm the actual plug, receptacle, circuit protection, and connection requirements with the manufacturer’s operating instructions before installation.
Air Distribution and Ducting
The FVO-400 provides 2,500 CFM of heated airflow through compatible discharge outlets.
Standard Dual 12-Inch Outlets
The standard outlet configuration features two 12-inch connections.
These allow heated air to be distributed through two suitable duct runs.
Alternative Single 16-Inch Outlet
Flagro also identifies a single 16-inch outlet configuration.
Confirm the required outlet arrangement when ordering.
Ducting Up to 50 Feet
The manufacturer identifies up to 50 feet of approved heated-air ducting for the standard FVO-400.
This is shorter than the 150-foot ducting capability published for the FVO-400RC.
Duct diameter, installation layout, restrictions, and allowable length must follow Flagro’s operating instructions.
Compatible Flagro Ducting
FV-HD12 — 12-Inch × 12-Foot Heated-Air Duct
Compatible with approved 12-inch discharge arrangements.
FV-HDG16 — 16-Inch × 25-Foot Heated-Air Duct
Compatible with an appropriate 16-inch outlet configuration.
Browse Commercial HVAC Accessories
Riello Burner Technology
The FVO-400 features Riello burner technology designed for dependable oil-fired heating.
Flagro identifies the following burner-related features:
- Nozzle preheater for cold-weather starting
- Updated low-temperature fuel pump
- Direct spark ignition
- Optional Tigerloop fuel system
The optional Tigerloop system is intended to help reduce fuel-system air-lock problems.
Burner inspection, servicing, and adjustments must follow the manufacturer’s operating instructions.
Portable Construction and Mobility
The Flagro FVO-400 is designed for temporary commercial heating applications.
Its portable cabinet includes two 16-inch flat-free wheels, helping operators reposition the heater on suitable surfaces.
The manufacturer lists overall dimensions of:
- Length: 70 inches
- Width: 29 inches
- Height: 52 inches
- Weight: 450 pounds
Appropriate lifting and handling procedures should be followed when loading, unloading, or transporting the heater.
Safety and Installation Requirements
The Flagro FVO-400 is commercial indirect-fired heating equipment and must be installed according to the manufacturer’s instructions.
Important considerations include:
- Provide adequate combustion air and ventilation.
- Safely route combustion exhaust away from occupied areas and building openings.
- Maintain required clearances from combustible materials.
- Use only approved fuel types.
- Confirm appropriate electrical power and circuit protection.
- Inspect the burner and fuel system before operation.
- Keep heated-air outlets unobstructed.
- Use compatible ducting within published installation limits.
- Place the heater on a stable, suitable surface.
- Follow applicable fire, mechanical, and fuel-storage regulations.
Indirect-fired heating does not eliminate the need for proper exhaust management or ventilation.
Why Choose the Flagro FVO-400?
The Flagro FVO-400 combines 390,000 BTU/hr heating capacity, 2,500 CFM airflow, and integrated fuel storage in a portable commercial heater.
Its Riello burner, stainless steel heat exchanger, flat-free wheels, and flexible discharge connections make it a practical choice for temporary construction and industrial heating.
For projects that do not require return-air recirculation or long duct runs, the FVO-400 provides a simpler alternative to the larger-airflow FVO-400RC.
Compare Other Flagro Indirect-Fired Heaters
Climate Control Solutions supplies additional heating equipment for different applications:
- Flagro FVO-400RC: 390,000 BTU indirect-fired heater with 4,000 CFM airflow and return-air recirculation.
- Flagro FVO-400RCBT: Bulk-tank recirculating model with a 118-gallon fuel tank.
- Flagro FVNP-400: Propane/natural gas indirect-fired alternative.
- Explore Commercial Heating Applications
Frequently Asked Questions About the Flagro FVO-400
How much heating capacity does the Flagro FVO-400 provide?
The FVO-400 delivers up to 390,000 BTU/hr of heating capacity.
What fuel does the FVO-400 use?
The heater operates on manufacturer-approved No. 1 or No. 2 fuel oil, diesel, or kerosene.
How large is the fuel tank?
The FVO-400 includes a built-in 42-gallon fuel tank.
How long can the heater operate on a full tank?
Flagro publishes approximately 14 hours of runtime. Actual operation depends on fuel availability, burner configuration, and operating conditions.
How much fuel does the FVO-400 consume?
The manufacturer lists approximately 2.75 gallons per hour for the referenced configuration.
How much airflow does the FVO-400 produce?
The unit provides 2,500 CFM of airflow using a 3/4 HP blower motor.
Does the FVO-400 require electrical power?
Yes. It operates on 115V electrical power and has a published current draw of 10.5 amps.
What size ducting can be used?
The standard heater includes two 12-inch outlets, with an alternative single 16-inch outlet configuration.
How much ducting can the FVO-400 support?
Flagro publishes a maximum ducting capability of up to 50 feet for approved configurations.
Does the FVO-400 support return-air recirculation?
No. The standard FVO-400 does not include the return-air inlet used on the FVO-400RC.
What is the difference between the FVO-400 and FVO-400RC?
Both provide 390,000 BTU/hr of heating capacity. The standard FVO-400 delivers 2,500 CFM and supports up to 50 feet of ducting, while the FVO-400RC provides 4,000 CFM, a 16-inch return-air inlet, and approved ducting up to 150 feet.
Is the FVO-400 suitable for temporary construction heating?
Yes. It is designed for properly installed temporary commercial and construction heating applications.
Request a Quote for the Flagro FVO-400
Climate Control Solutions supplies Flagro indirect-fired heaters, oil-fired construction heaters, and commercial temporary heating equipment nationwide.
Whether you need one FVO-400 for a construction project or multiple heaters for a commercial facility, our team can assist with equipment selection, fuel requirements, compatible ducting, and freight arrangements.
Contact Climate Control Solutions for current pricing and availability.
Phone: (800) 633-8711
Email: [email protected]
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