EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX 732-446-5362 E-Mail- info@ewccontrols.com
4
Sequence of
Operation for
Economy
Dry Bulb
Mode
The HK2000 monitors the outside
air sensor to determine if the actual
outdoor temperature is lower than
the Dry Bulb Economy Changeover
setting on the board.
When the
outdoor temperature is lower than the
setting on the board, the “OA Temp
Mode” LED on the panel will illuminate.
The HK2000 will attempt to satisfy
cooling demands with outside air.
If the outdoor temperature is higher
than the setting on the board, the
HK2000 will activate mechanical
cooling instead, to satisfy the cooling
demands.
When the HK2000 detects a demand
for cooling from the thermostat, and
the Outside Air Mode LED is
illuminated, it will activate the indoor
fan, lock out the mechanical cooling,
and energize all dampers to the
Outside Air Mode.
(Free Cooling)
At the same time it also starts the
economy termination. If the cooling
demand does not satisfy by the end of
15 minutes, The HK2000 will terminate
the economy operation, and energize
mechanical cooling to satisfy the
cooling demands. All dampers default
to the Return Air Mode, unless a Fresh
Air Cycle or Mechanical Cooling
Assistance occurs at the same time.
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48
54
60
66
72
78
DRYBULB ECONOMY
CHANGEOVER TEMP
Sequence of
Operation for
Economy
Enthalpy or
External
Device
Mode
If the Installer uses an Optional Enthalpy
Control,
The HK2000 will operate
based upon the action of the Enthalpy
Control.
When the Enthalpy Control
Closes
it’s contacts, the “Enthalpy
Mode”LED on the panel will illuminate.
The HK2000 will attempt to satisfy
cooling demands with outside air.
If the Enthalpy control
Opens
it’s
contacts, the HK2000 will activate
mechanical cooling to satisfy the cooling
demands.
When the HK2000 detects a demand for
cooling from the thermostat, and the
Enthalpy Mode LED is illuminated, it will
activate the indoor fan, lock out
mechanical cooling, and energize all
dampers to the Outside Air Mode.
(Free
Cooling)
If the HK2000 detects that the Enthalpy
control has opened it’s contacts, The
HK2000 will terminate economy
operation, and energize mechanical
cooling to satisfy the cooling demand. All
dampers default back to the Return Air
Mode, unless a Fresh Air Cycle occurs at
the same time.
NOTE:
Follow the instructions when
installing and setting up the Enthalpy
control. It should be mounted on the
outside air duct where it can sense the
outdoor conditions, regardless of the
position of the Outside Air damper.
NOTE:
The Economy Termination Timer
does not function when Enthalpy Mode
has been set. Mechanical cooling is
locked out until the Enthalpy control or
other device has opened it’s contacts.
NOTE:
Other control devices can be
connected to the Enthalpy input
terminals such as:
* Time Clock
* Manual Switch
* CO monitor/control
General Note:
*When the economy mode cycle has
been terminated by the Timer or by the
attached Enthalpy Control, mechanical
cooling will be used until the end of that
cooling cycle. The HK2000 will not
attempt another Economy Mode until
conditions are correct and the next
cooling demand occurs.
Mechanical
Cooling
Assistance
Return and
Outside Air
Sensor must
be connected
for this feature
to operate.
This feature will
not function if the
temperature is
below 40 or
above 80
degrees F.
This feature
requires the use
of the Return
Air Sensor.
Only during mechanical cooling
operations.
The HK2000 will monitor
return air temperature, and compare it
to outside air temperature. If the
outside air temperature is seven (7)
degrees lower than the return air
temperature, it will energize the
dampers to the Outside Air Mode
keeping the compressor energized.
The mechanical assistance will
remain energized until the Delta T,
between Outdoor and Return air has
drop to 3 degrees F or less. The Mixing
of these two air sources can reduce
the load on the mechanical cooling
system and satisfy the cooling
demand faster. That means real
energy savings is achieved and
extends the life of your compressor.
DO NOT install or completely close
off a return air damper when
operating in this mode.
Dry Bulb Mode
is locked out
below 40 and
above 80
degrees F.
