General Information
RT-SVX33E-EN
9
The system will continue to operate regardless of the
status of the filter switch.
Please note that on units equipped with factory installed
MERV 13 filters, a clogged filter switch with different
pressure settings will be installed. This switch will close
when the differential pressure is approximately 0.8' w.c.
and open when the differential falls to 0.7" w.c.
Compressor Disable (CPR1/2)
This input incorporates the low pressure control (LPC) of
each refrigeration circuit and can be activated by opening
a field supplied contact installed on the LTB.
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
contacts close.
If four consecutive open conditions occur during the first
three minutes of operation, the compressor for that circuit
will be locked out, a diagnostic communicated to the
remote panel (if installed), and a manual reset will be
required to restart the compressor.
Low Pressure Control
ReliaTel Control
When the LPC is opened for 1 continuous second, the
compressor for that circuit is turned off immediately. The
compressor will not be allowed to restart for a minimum
of 3 minutes.
If four consecutive open conditions occur during the first
three minutes of operation, the compressor will be locked
out, a diagnostic communicated to ICS™ if applicable, and
a manual reset will be required to restart the compressor.
High Pressure Control (Optional)
ReliaTel Control
The high pressure controls are wired in series between the
compressor outputs on the RTRM and the compressor
contactor coils. If the high pressure control switch opens,
the RTRM senses a lack of current while calling for cooling
and locks the compressor out.
On dual circuit units, if the high pressure control opens,
the compressor on the affected circuit is locked out. A
manual reset for the affected circuit is required.
Power Exhaust Control (Optional)
The power exhaust fan is started whenever the position of
the economizer dampers meets or exceed the power
exhaust setpoint when the indoor fan is on.
The setpoint panel is located in the return air section and
is factory set at 25%.
Lead/Lag Control (Dual Circuit Only)
Lead/Lag is a selectable input located on the RTRM. The
RTRM is configured from the factory with the Lead/Lag
control disabled. To activate the Lead/Lag function, simply
cut the wire connected to J3-8 at the RTRM. When it is
activated, each time the designated lead compressor is
shut off due to the load being satisfied, the lead
compressor or refrigeration circuit switches. When the
RTRM is powered up, i.e. after a power failure, the control
will default to the number one circuit compressor.
Evaporator Frost Control
This input incorporates the Frostat™ control (FOS)
mounted in the indoor coil and can be activated by closing
a field supplied contact installed in parallel with the FOS.
If this circuit is closed before the compressor is started, the
compressor will not be allowed to operate. Anytime this
circuit is closed 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 open.
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.
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 from performing it's design function.
Important:
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.
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
