Specifications

Application Guide • BALTIC - 0108 • 7 •
FEATURES AND BENEFITS STANDARD UNIT
Specic case of high pressure drop in the return air duct :
The problem becomes even more critical, when the return air
duct pressure drop is greater than 50 Pa.
Inthiscase,duetothedifcultyofthereturnairtogobackto
the rooftop, it is usual to have a lot more fresh air entering the
building than wanted, resulting in high running cost.
RUNNING COST
Scroll compressors / Refrigeration Circuits
ScrollcompressorsareusedontheBALTICformaximumef-
ciency and reliability, having overload protection.
Refrigerant circuits include compressors, condenser coils and
direct-drive condenser fans, evaporator coil and belt-driven
Centrifugal Indoor fans, expansion valves, high capacity dryers,
high pressure switches, low pressure switches, full refrigerant
charge.Inadditionyouwillndcheckvalves,defrostcontrol,
reversing valve on BAHM heat pump models.
Tandem
To improve part load efciency, Lennox has chosen to use
tandem assembly of compressor as often as possible. Starting
from the fact that rooftop works at PART LOAD most of the time,
tandemsimproveconsiderablytheefciency.
Forexample,whenonly50%oftheloadisneeded,oneofthe2
compressors in the tandem stops and the remaining compressor
has proportionally twice more exchanger surface to play with.
The gross COP can go from 2,95 at full load to 3,86 at part load
forsizeBAC045.(ARIstandard340.360-2000)
The second advantage of tandem is the improvement of opera-
ting limits with unloading. In extreme weather conditions, Baltic
R410A will continue to supply warm or cold air in unloading
compressors. For example size 45 can go up to 48°C outside
temperature.
Thermostatic Expansion Val-
ves
As it is important that the units
operateasefcientlyaspossible
and achieve maximum perfor-
mance at any running condition,
the thermostatic expansion val-
ves optimise the superheat of the
rooftop and, therefore, its overall
performanceefciency.
Alternate defrost
Because, this new rooftop has been designed to reduce life cycle
cost, the alternate defrost is a standard feature with 2 circuits
heatpumprooftops(Ebox).
When one circuit is in defrost the other is still running in heat-
pump mode reducing the use of costly electric heater.
This unique feature on the market place for small rooftop makes
the BALTIC a pionneer in terms of low life cycle cost.
Dynamic defrost (under patent INPI May 2003)
BALTIC is featuring the "dynamic defrost" concept.
Typical rooftop starts defrost cycle when the outside temperature
is below a certain value and repeat the cycle periodically.
This results sometimes in starting an expensive defrost cycle
when it is very cold outside but very dry, in other words when
the coil is not frozen.
After many test in the Lennox laboratories, it was found that
it is possible to exactly know if the coil is frozen, by analysing
the temperature difference between the coil and the outside
temperature.
With this built-in feature of the CLIMATIC™ 50, Lennox insures
to start a defrost cycle only when necessary, hence saving
energy.
A : High  in return air duct, B : Low  in return air duct
% fresh air ratio in the supply air