
U.S DESIGN STANDARDS
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HEA
T PUMP
CONDENSING UNIT ENGINEERING MANUAL
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ASHRAE STANDARDS SUMMARY
Method 2:
Method 3:
Introduce Untreated Ventilation Air: From an outside air opening, duct filtered, untreated ventilation air to Multi V indoor units.
This method can be employed in limited regions of the country where year round ambient conditions and air quality would
provide the indoor unit mixed air within LG’s published acceptable conditions. Refer to the "Building Ventilation" on page
48 for more information.
Coupled Pre-Treated Ventilation Air: From a common outside air inlet, filter and pre-treat the air temperature to room neutral
conditions, and duct the ventilation air to the ceiling cassette or recessed-ducted Multi V indoor units. Multi V indoor units
are designed for quiet operation and room air recirculation. Inherently, quiet fans cannot produce a significant amount
of static pressure. Thus, Multi V indoor units do not have the capability to “draw” ventilation air. Ventilation air must be
“pushed” to the indoor unit. Also, in the event the ventilation air is outside the indoor unit design parameters and the return
and ventilation air streams fail to mix properly before entering the indoor unit coil, air stratification may occur causing er-
ratic behavior of the Multi V indoor unit.
Operationally, the designer must consider many “what if” failure scenarios and understand the impact on building HVAC
system operations. Negative building pressure conditions may impact the indoor unit fan’s ability to pass the proper
amount of air over the indoor unit coil. This could occur if the ventilation system supply fan is disabled or ventilation damp-
ers malfunction while the building exhaust fans continue to operate. In this case, the indoor unit coil may desperately need
air as negative static pressure builds at the inlet of the indoor unit. On the other hand, when using non-ducted indoor unit
models in conjunction with a constant flow of ventilation air and the Multi V indoor unit supply air volume is reduced below the
ventilation air volume (the space temperature is satisfied), the ventilation air may flow backwards through the filter media and
return air grille. Captured particulate from the filter media may discharge into the room.
ASHRAE Standard 62.1-2010
USGBC. 2009. Green Building Design & Construction. Washington, DC. USGBC Staff. Page 535
* Amercian Society of Heating, Refrigeration and Air Conditioning Engineers, Inc. (ASHRAE) 62.1-2010, sections 6.2 and 6.3
Содержание Multi V mini
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