York R-407C manual Relief System, Evaporator Coil Protection, Condenser Coil Protection

FORM 100.50-EG1

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.

CO2 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.

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