York ECO R-407C - Manual (Page 41)

FORM 100.50-EG1
41 YORK INTERNATIONAL
Modulating Damper Economizer – economizer is
available with a modulating damper arrangements.
Modulating damper economizers shall have outdoor air
and return air dampers that are interlocked and posi-
tioned by fully modulating, solid state damper actua-
tors. The actuators shall be spring loaded so that the
outside air damper will close when power to the unit is
interrupted. The operation of the modulating economizer
shall be fully integrated into the cooling control system.
The modulating economizer control shall be via a dry
bulb sensor, single or dual enthalpy sensors.
Airflow Measurement – airflow measurement is avail-
able for the Modulating Damper Economizer option
listed above. Three options exist for airflow measure-
ment; minimum airflow and 100% air flow. Minimum
airflow measures airflow between 0 and the minimum
ventilation airflow up to 25% outside air. 100% airflow
measurement measures air flow from 0-100% of the
outside airflow.
RELIEF SYSTEM
Barometric Relief - building air exhaust shall be ac-
complished through barometric relief dampers installed
in the return air plenum. The dampers will open relative
to the building pressure.
Exhaust Air Fans - two (2) forward curved centrifugal
fans shall be installed in the return air plenum for posi-
tive power exhaust. Fan impellers shall be on a com-
mon shaft, driven by a single motor. The fans, motors
and drives shall be of the same quality and design as
specified for the supply air fan, except the fans shall be
Class I. Exhaust control options are on/off, modulating
discharge damper, or VFD fan speed control. On units
with non-modulating exhaust a barometric relief damper
is included to prevent outside air from entering in the
off cycle. Fans shall cycle on and off with building pres-
sure. On units with modulating exhaust and two posi-
tion control based on building pressure, a field-installed
static pressure sensor mounted in the conditioned
space or return air duct is required for damper and VFD
modulation.
EVAPORATOR COIL PROTECTION
Copper Fins – provided in lieu of aluminum fins.
Pre-Coated Fins – an epoxy-coated aluminum fin stock
to guard from corrosive agents and insulate against gal-
vanic potential. Used for mild seashore or industrial
locations.
CONDENSER COIL PROTECTION
Copper Fins – provided in lieu of aluminum fins.
Pre-Coated Fins – an epoxy-coated aluminum fin stock
to guard from corrosive agents and insulate against gal-
vanic potential. Used for mild seashore or industrial
locations.
Post-Coated Fins – Technicoat coil-coating process
used on condenser coils for seashore and other corro-
sive applications (with the exception of strong alkalis,
oxidizers, wet bromide, chlorine and fluorine in concen-
trations greater than 100ppm).
Hot Gas Bypass (Optional on Constant Volume;
Standard on VAV) – permits continuous, stable opera-
tion at capacities below the minimum step of unloading
by introducing an artificial load on the evaporator.
BACNet Communications Card – for BAS commu-
nications, a BACNet card is available with Ethernet
connection.
Compressor Sound Blankets – compressor acoustic
sound blankets for sound sensitive applications.
CO
2
Sensors – carbon dioxide sensors for occupied
space that operate demand ventilation control opening
outside air dampers to ventilate building.
Suction and Discharge Pressure Transducers – moni-
tor and readout of suction and discharge pressures.