Carrier WEATHERMASTER 50HJQ004-016 Product Data page 169

DESCRIPTION
( Enviro-Shield™ Option)
Standard, Al/Cu
Pre-Coated Al/Cu
Cu/Cu
E-Coated Al/Cu
E-Coated Cu/Cu
Al/Cu — Aluminum Fin with Copper Tube Coil
Cu/Cu — Copper Fin with Copper Tube Coil
Enviro-Shield — Family of Coil Protection Options
*See "Selection Guide: Environmental Corrosion Protection" Catalog No. 811-217 for more information
→
EconoMi$er IV
The EconoMi$er IV factory-installed economizer package
includes a gear-driven damper system that modulates the re-
turn air and outdoor air supply to the rooftop unit in order to
take advantage of "free cooling" with outdoor air when con-
ditions are suitable. The system utilizes industry proven
technology available for integrating the use of outdoor air
for cooling with mechanical cooling for 3 through 15-ton
rooftop units. The intuitive EconoMi$er IV solid-state con-
troller optimizes and enhances rooftop operation through
reduced energy consumption, optimal zone comfort, and ef-
ficient equipment cycling. This is accomplished by operating
the compressors when the outdoor air temperature is too
warm, integrating the compressors with outdoor air when
free cooling is available, and locking out the compressor
when outdoor air temperature is too cold. The detailed se-
quence of operation is described in the controls section
with a brief description of selected application items here.
Thermostat interface — The EconoMi$er IV control
was designed to work with conventional thermostats that
have Y1 (cooling stage 1), Y2 (cooling stage 2), W1 (heat
stage 1), W2 (heat stage 2), and G (fan). In addition, the
EconoMi$er IV will support an occupied/unoccupied
switch (typically integrated into the thermostat or thermi-
distat). When the switch is closed, it provides a 24 vac sig-
nal to the unit for occupied mode, and provides no signal
to indicate unoccupied mode. The EconoMi$er IV control
can be configured to allow different minimum economizer
damper positions and to allow the use of mechanical cool-
ing in the occupied mode.
→
Control features — The EconoMi$er IV controller pro-
vides superior functionality for rooftop unit operation.
EconoMi$er IV control features are included as follows:
Remote minimum position control — The EconoMi$er IV
controller can be used with a field-supplied and field-
installed remote minimum position control switch that will
enable and disable the EconoMi$er IV to open or close the
damper beyond the minimum position for modified ventila-
tion, providing 2 to 10 bdc output.
NOTE: Minimum position signal takes priority over the
DCV (Demand and Control Ventilation) maximum position
signal.
Demand control ventilation (DCV) — The EconoMi$er IV
has DCV capability when using an IAQ sensor. This sensor is
typically installed in the return duct or occupied space.
When implementing a DCV control scheme with the
CONDENSER COIL PROTECTION APPLICATIONS
Standard, Non-Corrosive Mild Coastal
X
LEGEND
ENVIRONMENT*
Moderate Coastal Severe Coastal
X
X
E-Coated — Extremely Flexible and Durable Epoxy Coating Uniformly
Applied to the Coil Surfaces
Pre-Coated — Epoxy Coating Applied to Fin Stock Material
EconoMi$er IV, the control algorithm will modulate the posi-
tion of the damper between two user-configured damper
positions, Maximum DCV Position and Minimum Occupied
position. Design airflow rates for these two damper positions
should be such that when the damper is at the Maximum
DCV position, enough fresh ventilation air will be brought in
to remove contaminants and CO
other than people (i.e., since in unoccupied mode). The
Maximum DCV position is intended to satisfy the IAQ "Base
Ventilation Rate." The Minimum Occupied position design
airflow rate should be sufficient to satisfy ventilation require-
ments for removing CO
the maximum occupancy.
IAQ sensors — EconoMi$er IV can be utilized with any
IAQ (CO
controller will modulate the outdoor air damper to provide
ventilation based on the sensor output and the IAQ setting
of the controller. When used, an IAQ sensor will modulate
the damper from the minimum position (base ventilation
rate based on CO
pancy ventilation rate).
→
Damper operation — The EconoMi$er IV allows the
damper to be configured for two adjustable damper posi-
tions including maximum position and occupied minimum
positions. The two (2) position damper capability is a
unique feature of EconoMi$er IV and includes operation
flexibility as follows:
1. Minimum Occupied Position: This adjustable position
allows a minimum ventilation airflow rate through the
unit during occupied periods (base ventilation rate).
2. Demand Control Ventilation (DCV) Maximum Posi-
tion: A DCV maximum occupied position is provided
when using an IAQ sensor for DCV. See DCV and
Control sections for sequence. The DCV Maximum
Position limits outdoor airflow into the rooftop when
the DCV routine overrides the mixed air sensor. Set-
ting the DCV Maximum Position of the outdoor-air
damper prevents large amounts of hot or cold air into
the space.
IMPORTANT: When the DCV Maximum Position is set
below the minimum position, the minimum position
overrides the maximum position, negating most DCV
functions.
905
Industrial Combined Coastal and Industrial
X
X
from all sources including people at
2
) sensor that provides a 2 to 10 vdc output. The
2
levels) to maximum position (full occu-
2
X
generated by sources
2
169