Greenheck Fan Modular Make-Up Air Unit DGX - Manual (Page 8)

Our Warranty
Greenheck warrants this equipment to be free from defects in material and workmanship for a period of one year from the
purchase date. Any units or parts which prove defective during the warranty period will be replaced at our option when returned
to our factory, transportation prepaid. Motors are warranted by the motor manufacturer for a period of one year. Should motors
furnished by Greenheck prove defective during this period, they should be returned to the nearest authorized motor service
station. Greenheck will not be responsible for any removal or installation costs.
As a result of our commitment to continuous improvement, Greenheck reserves the right to change specifications without
notice.
Greenheck P.O. Box 410 • Schofield, WI 54476-0410 • Phone (715) 359-6171 • greenheck.com
General: Make-up air unit shall be as manufactured by
Greenheck or approved equal provided all specifications are
met. Greenheck Model DGX equipment is used as the basis of
design. Performance to be as scheduled on plans. Make-up air
unit shall be ETL listed to ANSI Z83.4 -1999, CSA 3.7 - M99 (for
100% outdoor air) or ANSI Z83.18-2000 (for recirculation).
Gas Train and Controls: Direct gas-fired system shall have
a draw through design and field adjustable burner baffles.
Gas trains up to 400,000 Btu/hr shall include a direct spark
ignition system. Gas trains greater than 400,000 Btu/hr shall
include a pilot ignition system and shall have digital coded
fault indicator capability. Fault indicator shall provide service
history by storing codes for the last five faults. Dual safety
shutoff valves shall be industrial duty and use 120 VAC control
signals. Temperature control shall incorporate a Maxitrol
electronic modulation control system.
Unit Casing and Frames: Unit shall be of internal frame type
construction of galvanized steel. All frames and panels shall
be G90 galvanized steel. Where top panels are joined there
shall be a standing seam to insure positive weather protection.
All metal-to-metal surfaces exposed to the weather shall be
sealed, requiring no caulking at job site. All components shall
be easily accessible through removable doors.
Insulation: Unit casing to be lined with 1 inch fiberglass
insulation where specified. Insulation shall be in accordance
with NFPA 90A and tested to meet UL 181 erosion requirements.
Double wall shall be provided where specified.
Fan Section: Centrifugal fans shall be double width, double
inlet. Fan and motor shall be mounted on a common base and
shall be internally isolated. All blower wheels shall be balanced.
Ground and polished steel fan shafts shall be mounted in
permanently lubricated ball bearings or ball bearing pillow
blocks. Bearings shall be selected for a minimum (L10) life in
excess of 100,000 hours at maximum cataloged speeds.
Motors and Drives: Motors shall be energy efficient,
complying with EPACT standards, for single speed ODP
and TE enclosures. Motors shall be permanently lubricated,
heavy duty type, matched to the fan load and furnished at the
specified voltage, phase and enclosure. Drives shall be sized
for a minimum of 150% of driven horsepower. Pulleys shall
be cast and have machined surfaces, 15 horse power and less
shall be supplied with an adjustable drive pulley.
Electrical: All internal electrical components shall be prewired
for single point power connection with exception of the larger
evaporative cooling sections. All electrical components shall
be UL listed, recognized or classified where applicable and
wired in compliance with the National Electrical Code. Control
center shall include motor starter, control circuit fusing,
control transformer for 24 VAC circuit,
integral disconnect switch and terminal
strip. Contactors, Class 20 adjustable
overload protection and single phase
protection shall be standard.
Filter Section: Filter section shall be
designed such that velocities across
the filters do not exceed 550 feet per
minute. Filters shall be 2-inch washable
aluminum mesh or 2-inch disposable.
Weatherhood: Weatherhood shall be
constructed of G90 galvanized steel
with birdscreen mounted at the intake.
Recirculation (optional): Recirculation
airflow shall be controlled by adjustment
of return damper position. Input signal
for return damper shall be from building
pressure sensors, potentiometer,
external signal, or manual switch.
Recirculated air shall not be permitted
to pass across the burner. Return air
shall be filtered.
Variable Volume (optional): Volume shall be varied by either
a 2-speed motor or variable frequency drive. Input signal for fan
speed shall be from building pressure sensors, potentiometer,
external signal, or manual switch. A self-adjusting burner
bypass damper shall maintain a constant air volume across
the burner to ensure proper gas combustion. Bypass damper
shall operate automatically without an electronic signal.
Cooling Coil (optional): Direct expansion (DX) or chilled
water coil shall be factory tested and rated in accordance
with ARI 410. Coils shall have copper tubes with permanently
expanded aluminum fins, 12 fpi or less. DX coils shall be
equipped with distributors to receive expansion valves at the
liquid connections. Drain pans shall extend at least 12 inches
downstream of coil and be sloped to drain connection. Cooling
coil shall meet UL 1995 specifications for non-protected coil.
Evaporative Cooling Section (optional): Evaporative
cooling section shall include a galvanized steel housing with
louvered intake, 2 inch aluminum mesh filters and a stainless
steel evaporative cooling module all provided by the make-up
air unit manufacturer. The louver shall be stationary type with
drainable blades, and be designed to withstand wind loads of
25 PSF. Evaporative cooling media shall be 12 inches deep,
with a UL 900 class II fire rating for a cooling effectiveness of
90%. Drain and overflow connections shall be piped through
the side of the evaporative cooling section.
Copyright © 2007 Greenheck Fan Corp. • Catalog DGX Rev. 4 March 2007 SP
Typical Specifications