HE4XRT
Due to continuing product development, specifications are subject to change without notice.
© 2012 RenewAire LLC
134775_005 HE4XRTMan_Jan12.indd Revised 01/2012 www.renewaire.com
Page 4
Inside Ductwork System
Follow Engineer’s Ductwork Design
Ductwork should be designed by an engineer to allow the unit to
provide the required airflow.
Duct Insulation
If the inside ducts run through un-conditioned spaces, they must
be insulated, with a sealed vapor barrier on both inside and
outside of insulation.
Use Static Taps in Doors to Measure Airflow Rates
See “Cross-Core Static Drop” in MEASURING AIRFLOW table. These
may be used to directly measure airflow in the unit.
Change Sheaves if required to Set and Balance Air Flow
In most applications, the airflow rate for both the Fresh Air and
the Exhaust Air should be roughly equal (or “balanced”) for best
performance of the HE4XRT Unit.
In most cases, the job engineer will specify flow rates and ESP
requirements. The blower motors will also be specified to provide
the required performance.
See unit specification sheet for CFM/ESP curves for available
horsepower motors.
See drawings below for examples of some common installation
approaches:
Sound Attenuation
General Practices
Take these simple steps to attenuate noise from the unit.
Outside the building:
The exhaust hood is the primary source of noise outside the
building. When practical, orient the exhaust air hood to point
away from houses or public areas.
At the Curb:
Cut the holes in the roof deck to fit closely around the duct(s)
passing through the roof deck. Seal all gaps around the duct(s)
at the roof deck.
Ducts:
Make sure the ductwork at the unit outlets is stiff enough to
resist the flexure and resulting booming associated with system
start-up and shut-off, as well as the turbulent flow conditions at
the blower outlets.
In general, provide smooth transitions from the ERV’s outlets to the
duct. The ducts connecting to the outlets should be straight for a
sufficient distance, with gradual transitions to the final duct size.
These guidelines are consistent with SMACNA recommended duct
layout practices for efficient and quiet air movement. Follow
SMACNA guidelines.
Radiated Noise
The HE4XRT is insulated with high-density fiberglass. This provides
significant attenuation of radiated sound from the unit itself.
The outlet ducts can be significant sources of radiated sound
as well. The FA duct should be insulated for sound control. This
insulation should start at the unit. At a minimum the first ten
feet of duct should be insulated. All parts of the FA and RA ducts
located in a mechanical space with noise-generating equipment
also should be insulated for sound control, both to minimize
sound radiation out of the FA duct, and also to control sound
radiation into both ducts.
Aerodynamic (Velocity) Noise
When sound attenuation is a design concern, the primary
consideration is velocity noise at the unit’s Fresh Air blower
outlet. The average velocity at the Fresh Air blower outlet is
1230 FPM when the unit is operating at 4290 CFM. The average
velocity at the Exhaust Hood outlet is 1420 FPM when the unit is
operating at 4290 CFM.
Danger of Electrical Shock when servicing an installed unit.
ALWAYS DISCONNECT POWER SOURCE BEFORE
SERVICING! More than one disconnect switch may be
required.
Proper Wiring Size Selection and Wiring Installation
are the Responsibility of the Electrical Contractor.
Electrical Specifications
Electrical Options are identified on the Unit Label (located near
electrical box). Find the complete Unit Model Number in the
lower left corner of the Unit Label.
HE-4X_RTV
ROOF
Unit connected to
Return Duct of
nearby AHU.
HE-4X_RTR
Rooftop AHU
ROOF
RTR Unit with dedicated ducts
collecting Room Air.
Fresh Air is ducted into
horizontal return connection
of adjacent AHU.
HE-4X_RTV
ROOF
Stand-alone installation with
independent ducts for
exhaust and supply air.
AHU
