The HK2000 Fresh Air and Economizer panel provides
intelligent and economical control of residential and light commercial
heating and cooling systems.
Fresh Air Mode
The need for Fresh Air has been increasing
over the past 10 years. Homebuilders are building tighter homes with
no provisions for fresh air. Older homes have been found to have damp
stale air, and some office buildings are deemed to have "sick building
syndrome". EWC Controls is introducing the cure.
During Fresh Air operation the HK2000 has the
flexibility to bring in as much, or as little Fresh Air as needed. The
cycle timer is adjustable from 0 (off) to 12 cycles (continuous) per
hour. When the cycle timer is set to 4 cycles per hour, representing
20 minutes of Fresh Air, the HK2000 will activate the Fresh Air mode
for 5 minutes in the 1st quarter hour, 5 minutes in the 2nd quarter
hour, 5 minutes in the 3rd quarter hour and 5 minutes in the 4th quarter
The cycles per hour feature on the HK2000 is
designed to help maintain the Indoor Comfort level and satisfy Fresh
Air requirements of the home owners and occupants during extreme weather
conditions as well as minimizing the load on the HVAC system.
The HK2000 also offers the added flexibility
of controlling the exhaust air, the return air as well as the fresh
air intake. This built in feature prevents over pressurization in homes
and buildings maintaining a safe number of air changes per hour helping
to prevent, and cure, a "sick building or home".
The economizer feature of the HK2000 allows
for the use of outside air to satisfy the need of indoor cooling. This
form of "Free Cooling" is monitored and controlled using several
Dry Bulb Method, also known as outdoor temperature
method, will sense the outside air temperature and determine if that
air is acceptable to use to satisfy a cooling call. The determining
temperature range for this method is adjustable by the installer between
42° F and 78° F. The outside air temperature is monitored using the
supplied OAS sensor.
If the outside temperature is above the adjusted
set point on the HK2000 the system will start the air conditioning unit.
If the system goes into the dry bulb method, using the outside air for
cooling, the HK2000 will also monitor its success. If it does not satisfy
the cooling call within 15 minutes using the outside air, the HK2000
will shut down the economy mode and start the air conditioning system.
During Enthalpy Method an optional enthalpy
control can be used to sense the outside air for appropriate conditions.
Enthalpy controls allow for a more accurate method of measuring temperature
and humidity when using the economizer function. The enthalpy mode will
not use the 15-minute timer described above. The enthalpy control will
either satisfy the cooling call using outside air or energize the air
conditioning using its own settings.
The most economical advantage of the HK2000
is the Mechanical Cooling Assistance mode. In this mode the HK2000 will
monitor the return air temperature through the use of an optional return
air sensor and compare it to the outside air temperature. If the outside
air is 7° F cooler than the return air, the HK2000 will bring in the
outside air and mix it with the return air. The mixing of these two
sources will reduce the load on the air conditioning and satisfy the
cooling demand sooner. This correlates to real savings.
The HK2000 can control up to three (3) 24 VAC
dampers: Outside Air, Return Air, and Exhaust Air.
The HK2000 is suitable for all new construction
and most retro-fit applications.