American Standard YSC036A Installation, Operation And Maintenance Manual page 11

General Information
Evaporator Frost Control
(ReliaTel™ Option)
This input incorporates the Frostat™
control (FOS) mounted in the indoor
coil circuit and can be activated by
closing a field supplied contact
installed in parallel with the FOS.
If this circuit is open before the
compressor is started, the
compressor will not be allowed to
operate. Anytime this circuit is
opened for 1 continuous second
during compressor operation, the
compressor for that circuit is
immediately turned "Off" . The
compressor will not be allowed to
restart for a minimum of 3 minutes
should the FOS close.
(Electro Mechanical Option)
This input incorporates the Frostat™
control (FOS) mounted in the indoor
coil circuit and can be activated by
opening a field supplied contact
installed in series with the FOS.
If this circuit is open before the
compressor is started, the
compressor will not be allowed to
operate. Anytime this circuit is
opened during compressor
operation, the compressor for that
circuit is immediately turned "Off" .
The compressor will restart when the
FOS closes.
Smoke Detector Sensor
(Optional)
This sensor is only applicable on
units equipped with a RTOM. It
provides high limit "shutdown" of
the unit and requires a manual reset.
The sensor is used to detect smoke
due to fire in the air conditioning or
ventilation ducts.
Note: The supply and return air
smoke detectors are
designed to shut off the unit if
smoke is sensed in the supply
air stream or return air
stream. This function is
performed by sampling the
airflow entering the unit at
the return air opening. Follow
the instructions provided
below to assure that the
airflow through the unit is
sufficient for adequate
sampling. Failure to follow
these instructions will
prevent the smoke detectors
RT-SVX21F-EN
from performing it's design
function.
Note: Airflow through the unit is
affected by the amount of dirt
and debris accumulated on
the indoor coil and filters. To
insure that airflow through
the unit is adequate for
proper sampling by the
return air smoke detector,
complete adherence to the
maintenance procedures,
including recommended
intervals between filter
changes, and coil cleaning is
required.
Note: Periodic checks and
maintenance procedures
must be performed on the
smoke detector to insure that
it will function properly. For
detailed instructions
concerning these checks and
procedures, refer to the
appropriate section(s) of the
smoke detector Installation
and Maintenance Instructions
provided with the literature
package for this unit.
In order for the supply air smoke
detector or return air smoke detector
to properly sense smoke in the
supply air stream or return air
stream, the air velocity entering the
smoke detector unit must be
between 500 and 4000 feet per
minute. Equipment covered in this
manual will develop an airflow
velocity that falls within these limits
over the entire airflow range
specified in the evaporator fan
performance tables.
There are certain models, however, if
operated at low airflow, will not
develop an airflow velocity that falls
within the required 500 to 4000 feet
per minute range. For these models,
the design airflow shall be greater
than or equal to 1000 feet per minute
MINIMUM.
Phase Monitor (Optional)
ReliaTel Control Only
This sensor monitors voltage
between the 3 conductors of the 3
phase power supply. Two LED lights
are provided. The green light
indicates that a balanced 3 phase
supply circuit is properly connected.
The red light indicates that unit
operation has been prevented. There
are two conditions that will prevent
unit operation.The power supply
circuit is not balanced with the
proper phase sequence of L1, L2, L3
for the 3 conductors of a 3 phase
circuit. The line to line voltage is not
between 180 volts and 633 volts
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