user manual
The Liebert GLYCOOL free-cooling system is inte-
grated with a glycol cooled Challenger 3000.
At outdoor temperatures below 35°F (1.6°C), the
GLYCOOL coil is capable of providing total system
capacity. At outdoor temperatures between 35° and
65°F (1.6° and 18.3°C), the unique modulating valve
permits partial cooling of the space by the GLY-
COOL coil with the DX system picking up the rest of
the load. Above 65°F (18.3°C) the unit functions as a
glycol unit and all the cooling is accomplished by the
DX system. When cooling is required, the three-way
modulating valve and water regulating valve direct
glycol (from the heat rejection loop) to the
Econ-O-Coil located upstream of the evaporator coil,
to the condenser, or to both.
The GLYCOOL system contains all the standard fea-
tures of a glycol cooled system plus the following.
A solid-state temperature monitor compares the room
air temperature and entering glycol temperature.
When air temperature is higher than glycol tempera-
ture, the monitor communicates to the microproces-
sor control that “free-cooling” is available.
The GLYCOOL coil is strategically located in the
return air stream of the environmental control system.
This coil is designed for closed-loop applications using
properly treated glycol solutions.
The air is first filtered before entering the coil and
then is either precooled or totally cooled before enter-
ing the refrigeration coil. The glycol flow to the coil is
controlled by a pre-piped modulating three-way
valve. When supplied with a 45°F (7.2°C) glycol solu-
tion, the coil is sufficiently sized to offer the identical
cooling capacity as is obtained during the refrigera-
tion cycle of the compressor.
The GLYCOOL Three-Way Control Valve opens full
anytime the temperature of the glycol solution is below
room temperature, to take full advantage of all possi-
ble free cooling. As the outdoor ambient drops, the
three-way control valve modulates the flow to the
GLYCOOL coil. It maintains constant temperature in
the room and includes operating linkage and electronic
motor. Unlike other valves of this nature, there is no
over travel linkage or end switches to be adjusted.
A head pressure operated glycol regulating valve
accurately controls the condensing temperature and
system capacity for various entering glycol tempera-
tures. The valve has three-way action.
The Liebert manufactured drycooler is constructed of
aluminum with a copper tube aluminum fin coil. The
low profile design features multiple direct drive pro-
peller type fans, balanced to the heat rejection load.
An integral, factory wired and tested control panel
reduces installation time.
For high pressure applications, the GLYCOOL sys-
tem can be equipped with components rated at 300
psig (2069 kPa).
The dual pump package features two full size glycol
pumps, each capable of providing sufficient flow for
system operation. A flow switch will sense the loss of
flow, should the lead pump fail, and automatically
command the standby pump to start. The complete
system includes dual pump housing, pumps, lead-lag
switch and flow switch (for field installation). The
dual pump package provides redundancy, protecting
against costly downtime in the computer room.
Quiet-Line Drycoolers can help your facility meet the
strictest noise codes, and do so at less cost than tradi-
tional drycoolers with acoustical shielding.
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