Return Air Smoke Detector; Economizer Start-Up; Compressor Start-Up - American Standard YSC036A Installation, Operation And Maintenance Manual

Start-Up
Return Air Smoke
Detector
The return air smoke detector is
designed to shut off the unit if smoke
is sensed in the return air stream.
Sampling the airflow entering the
unit at the return air opening
performs this function.
In order for the smoke detector to
properly sense smoke in the return
air stream, the air velocity entering
the 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 the minimum CFM
specified in the table provided below.
Failure to follow these instructions
will prevent the smoke detector from
performing its design function.

Economizer Start-Up

ReliaTel Control
Using the Service Test Guide in
Table 10, momentarily jump across
the Test 1 & Test 2 terminals on LTB1
one time to start the Minimum
Ventilation Test.
Electro Mechanical Control
Using the Service Test Guide perform
the proper test mode connections.
1. Set the minimum position
setpoint for the economizer to
the required percentage of
minimum ventilation using the
setpoint potentiometer located
on the Economizer Control
(ECA).
The economizer will drive to its
minimum position setpoint,
exhaust fans (if applicable) may
start at random, and the supply
fan will start when the SERVICE
TEST is initiated.
RT-SVX21F-EN
WARNING
Rotating Components!
During installation, testing, servicing
and troubleshooting of this product
it may be necessary to measure the
speed of rotating components. Have
a qualified or licensed service
individual who has been properly
trained in handling exposed rotating
components, perform these tasks.
Failure to follow all safety
precautions when exposed to
rotating components could result in
death or serious injury.
The Exhaust Fan will start
anytime the economizer damper
position is equal to or greater
than the exhaust fan setpoint.
2. Verify that the dampers stroked
to the minimum position.
ReliaTel Control
Momentarily jump across the Test 1
& Test 2 terminals on LTB1 one
additional time if continuing from
previous component start-up or until
the desired start-up component Test
is started.
Electro Mechanical Control
Using the Service Test Guide perform
the proper test mode connections.
3. Verify that the dampers stroked
to the full open position.
4. To stop the SERVICE TEST, turn
the main power disconnect
switch to the "Off" position or
proceed to the next component
start-up procedure. Remove
electro mechanical test mode
connections (if applicable).

Compressor Start-Up

1. Attach a set of service gauges
onto the suction and discharge
gauge ports for each circuit.
Refer to the refrigerant circuit
illustration in the Service Facts.
ReliaTel Control
Momentarily jump across the Test 1
& Test 2 terminals on LTB1 one
additional time if continuing from
previous component start-up or until
the desired start-up component Test
is started.
Electro Mechanical Control
Using the Service Test Guide perform
the proper test mode connections.
Scroll Compressors
a. Once each compressor has
started, verify that the
rotation is correct. If a scroll
compressor is rotating
backwards, it will not pump
and a loud rattling sound can
be observed.
b. If the electrical phasing is
correct, before condemning a
compressor, interchange any
two leads (at the compressor
Terminal block) to check the
internal phasing. If the
compressor runs backward
for an extended period (15 to
30 minutes), the motor
winding can overheat and
cause the motor winding
thermostat to open.
2. After the compressor and
condenser fan have started and
operated for approximately 30
minutes, observe the operating
pressures. Compare the
operating pressures to the
operating pressure curve in the
Service Facts.
3. Check system superheat. Follow
the instruction listed on the
superheat charging curve in the
Service Facts.
Superheat should be within ±5 F
of the superheat chart value.
4. Repeat steps 1 through 4 for each
refrigerant circuit.
5. To stop the SERVICE TEST, turn
the main power disconnect
switch to the "Off" position or
proceed to the next component
start-up procedure. Remove
electro mechanical test mode
connections (if applicable).
Dehumidification Option
Momentarily jump across the Test 1
and Test 2 terminals of the LTB1 until
the unit enters test mode 7. (See
Table 6.) Once the unit is in the
reheat test mode, verify that the 3
way valve has shifted to the reheat
position and that the supply
temperature rises 10 deg F more than
when in cooling mode stage 2.
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