Direct-Fired Indoor/Outdoor Make-up Air (MDB/MRB)
Designed to provide an economical and efficient means of supplying tempered make-up air. All units allow indoor or outdoor mounting and have a 100% thermal efficiency. 100% Make-up Air System is heated directly by the gas flame, eliminating the need for a heat exchanger and associated efficiency losses of indirect-fired equipment.
Return Air Direct-Fired Systems can be used as combination make-up air and heating/ventilating units, requiring the capability of operating with recirculated air as well as make-up air.
- 100% thermal efficiency (92% sensible) results in lower fuel bills
- Natural or propane gas manifolds are factory-assembled to provide flexible fuel options and reduce field-installation costs
- Factory-wired electrical panel with numbered terminals significantly simplifies field wiring
- 100% factory flame-tested
- Weatherproof roof with drip ledge protects from water being drawn into the unit from the roof
- 18-gauge galvanized steel casing provides high corrosion protection for long life
- Adjustable drives through 10 HP simplify air balancing
- Four access doors provide maximum access for easy adjustments and service
- 22:1 firing rate turndown for optimum temperature control
- Units are third party certified by ETL
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Model MDB
- Input ratings up to 7,425,000 Btu/hr
- Maximum airflow capability of 60,000 CFM
Model MRB
- Input ratings up to 5,500,000 Btu/hr
- Maximum airflow capability of 41,000 CFM
- Maximum return air capability of 75%
- A minimum 25% outside air must always be supplied to the building
Both MDB & MRB
- Painted unit casing
- Inlet hood, unpainted* with or without filters – field installed for model sizes 125 and above
- Insulated V-bank 2” filters section, unpainted* with permanent, throwaway, or Farr30/30 filters – field installed for model sized 125 and above and vertical units
- Inlet damper, unpainted* – field installed for models sizes 125 and above and vertical units
- Pillow block bearings – model sizes 110 and 118
- Internal spring blower and motor vibration isolation – requires pillow block bearings
- Extended grease lines – requires pillow block bearings
- Dead front non-fused disconnect switch
- High and low gas pressure switches
- Building management system control options
- Control power transformer for 208, 230, 460, or 575V supply voltage
- Timed freeze protection
- Mild temperature inlet on/off duct stat
- Motor starter auxiliary contacts for starting exhaust fan
- Double pole double throw (DPDT) control relays
- Circuit analyzer for 10 to 12 points
Accessories
- NEMA 1 remote control panel
- Discharge damper, unpainted*
- Discharge louvers – 3- or 4-way, unpainted*
- Evaporative cooler with pre-filter with 12” Celdek or Glasdek media – optional rain hood with filter
- Evaporative cooler fill and drain kits, manual or automatic with optional freeze stat
- Inlet stand, painted in 24” or 48” heights, with or without inlet screen – vertical units only
- Vibration hanger – suspended units only
- Vibration feet – slab mounted units only
- Box style disconnect switch
*Painted options available
