PRODUCT
SPECIFICATIONS
AND ENGINEERING
HRV LT-15, LT-20
INFORMATION
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HEAT RECOVERY VENTILATOR
SUBMITTAL DATA
746-7-00
ALDES Model HRV LT-15 and LT-20 are
compact heat recovery ventilators designed to
exhaust stale indoor air and supply fresh air
from outdoors. When operated at full speed,
the LT-15 unit can meet the general ventilation
requirements (0.35 air changes per hour—
ASHRAE 62-1989) of a home up to 2800 sq. ft,
and the LT-20 of a home up to 4000 sq. ft. (On
a smaller home, they can be operated at lower
speed, reserving excess capacity for tempo-
rary increases in humidity or other contami-
nants.) They are technically advanced con-
trolledmechanicalventilationsystemsdesigned
to meet the requirements of modern, tightly
built and highly insulated homes. They provide
a consistent supply of fresh air while lowering
heating costs during the winter by transferring
heatfromtheexhaustairtothefreshairstream.
During the summer they also reduce the load
on the air conditioner by lowering the tempera-
ture of the fresh outdoor air. (For southern
climates, where air conditioning costs are the
major concern, one of the ERV models should
be considered, because of their ability to re-
duce the humidity of the fresh air as well as
lowering the temperature.) The systems pro-
vide an economical solution for excessive in-
door humidity, odors, stuffiness, and other in-
door air pollutants.
ALDESHRVLT-15,LT-20
Air to Air Heat Recovery Ventilator
LT-15 PART NO. 28 045
LT-20 PART NO. 28 047
Disadvantages: Higher installed cost for addi-
tional ductwork. Unless bedrooms are provided
Disadvantages: Higher operating costs when
air handler is required to distribute fresh air.
with some form of zoned heat, cooler supply air Greater potential for draft with high air volumes
to bedrooms may result in cooler temperature in circulating at room temperature.
As the two air streams pass through the HRV,
they are separated by thin plates of aluminum
inthecore. Theairstreamsdonotmix, sothere
is no recontamination of the fresh air by stale
air. Heatpassesthroughthethermallyconduc-
tivealuminumfromthewarmerairstreamtothe
colder air stream, recovering most of the en-
ergy otherwise lost to the outdoors.
these spaces.
FULLY INTEGRATED WITH FORCED AIR
The exhaust air is drawn from the return duct
and fresh air is supplied downstream in the
HALF-DUCTED SYSTEM
Similar to fully ducted system, except supply air
return duct or in the forced air heating supply
delivered to a central location or to the return of
ducting.
a forced air system.
Advantages: Lowest installation costs, with mini-
Advantages: Lowinstallationcosts,asductwork
malductwork. Thoroughmixingoffreshairthrough-
is reduced. Good tempering of outdoor air when
out dwelling. Good tempering of outdoor air.
DUCTING CONSIDERATIONS
ducted to the return of the furnace or heat pump.
Equally important to providing fresh air supply Good ventilation efficiency, as pollutants are
andexhaustofstaleairisthemeansofassuring exhausted with minimal mixing in the occupied
Disadvantages: Requiresforcedairhandlerto
run continuously with the ventilation system, or
internal distribution of fresh air throughout the
occupiedspace(s)andexhaustofstaleairfrom
spaces. Quietbathroomandkitchenexhaustas internalshort-circuitingofsupplyandexhaustwill
compared to conventional fans for these areas. occur in the ducting. Higher electrical operating
highly polluted areas. The designer/specifier Reduces cost of equipment to ventilate these
should select the means of internal distribution areas. Reduced roof and wall penetrations for
when the ventilation system is planned. Three independent fans.
popular methods are detailed below, with ad-
costs since air handler is required to distribute
fresh air. Greater potential for draft with high air
volumes circulating at room temperature.
vantages and disadvantages for each type.
GENERAL FEATURES
Thermally conductive aluminum heat exchange core, cross-flow design, easily
removed for cleaning or service.
Efficient multi-speed motor drives a centrifugal blower in each air stream. Quiet,
high efficiency PSC motor. 120 V., 1.4 Amps
FULLY DUCTED SYSTEM
Dedicated exhaust and supply ducting to all
spaces that can be closed. Fresh air to bed-
rooms, dens, office spaces, etc. Exhaust air
from zones that produce high levels of pollut-
ants, such as kitchen, bathrooms, laundry, util-
ityroomswithstoredhouseholdchemicals, etc.
Washable filters on each air stream protect the core. Easy to access and clean.
Automatic defrost system activates when outdoor temperature falls below
25 °F (-4 °C). The defrost cycle is preset at the factory so that after 17 minutes of
outdoor temperature below this set point, the motor driven damper closes the
outdoor air connection, and opens the defrost port to draw warm indoor air across
the core. After 3 minutes of defrost operation, the damper reverses to restore fresh
air supply and close the defrost port. The 17 minute normal ventilation and 3
minute defrost cycle continue until outdoor air temperature rises above
25 °F (-4 °C). During the 3 minute defrost cycle, the HRV operates at high speed.
The cycle times are installer selectable to meet the needs of different climates and
operating conditions.
Advantages: Lowest operating costs, relying
onlyonthesmalllowpowerblowersoftheHRV,
instead of large central air handlers in furnaces
orheatpumps. Improvedventilationefficiency,
as pollutants are exhausted with minimal mix-
ing in the occupied spaces and freshest air is
delivered to zones where occupants spend
large amount of time. Quiet bathroom and
kitchen exhaust as compared to conventional
fans for these areas. Reduced cost of equip-
ment to ventilate these areas. Reduced roof
and wall penetrations for independent fans.
Casing is heavy gauge pre-painted steel to protect against corrosion, and minimize noise.
Installation accessories and controls make installation simple.
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