X.
INSTALL ELECTRICAL ACCESSORIES
Refer to the individual instructions packaged with kits or acces-
sories when installing.
XI.
START-UP
CAUTION:
To prevent compressor damage or personal
injury, observe the following:
• Do not overcharge system with refrigerant.
• Do not operate unit in a vacuum or at negative pressure.
• Do not disable low-pressure switch
In scroll compressor applications:
• Dome temperatures may be hot.
• In 3-phase application, incorrect phasing will cause
reverse rotation, resulting in elevated noise levels, equal-
ized pressures, and reduced current draw. Correct by
reversing power connection L1 and L2 on contactor.
CAUTION:
To prevent personal injury wear safety
glasses, protective clothing, and gloves when handling
refrigerant and observe the following:
• Back seating service valves are not equipped with
Schrader valves. Fully back seat (counter clockwise)
valve stem before removing gage port cap.
• Front seating service valves are equipped with Schrader
valves.
CAUTION:
Do not vent refrigerant to atmosphere. Re-
cover during system repair or final unit disposal.
Follow these steps to properly pump down a system and avoid
negative suction pressure.
1. Fully back seat (open) liquid and vapor tube service valves.
2. Unit is shipped with valve stem(s) front seated (closed) and
caps installed. Replace stem caps after system is opened to
refrigerant flow. Replace caps finger-tight and tighten with
wrench an additional 1/12 turn.
3. Close electrical disconnects to energize system.
4. Set room thermostat at desired temperature. Be sure set
point is below indoor ambient temperature.
5. Set room thermostat to COOL and fan control to ON or
AUTO mode, as desired. Operate unit for 15 minutes.
Check system refrigerant charge.
A.
Sequence of Operation
Turn on power to indoor and outdoor units. Transformer is
energized.
On a call for cooling, thermostat makes circuits R-Y and R-G.
Circuit R-Y energizes contactor, starting outdoor fan motor and
compressor circuit. R-G energizes indoor unit blower relay,
starting indoor blower motor on high speed.
When thermostat is satisfied, its contacts open, de-energizing
contactor and blower relay. Compressor and motors stop.
If indoor unit is equipped with a time-delay relay circuit, the
indoor blower will run an additional 90 sec to increase system
efficiency.
XII.
CHECK CHARGE
A.
Unit Charge
Factory charge is shown on unit rating plate. Adjust charge by
following procedure shown on charging tables located on unit.
NOTE:
If superheat or subcooling charging conditions are not
favorable, charge must be weighed in accordance with unit rating
plate
±
0.6 oz/ft of 3/8-in. liquid line above or below 15 ft
respectively.
EXAMPLE:
25 ft - 15 ft = 10 ft X 0.6 oz/ft = 6 oz of additional charge
B.
Cooling Only Procedure
The following procedure is valid when indoor airflow is within
±
21% of its rated CFM.
1. Operate unit a minimum of 10 minutes before checking
charge.
2. Measure suction pressure by attaching a gage to suction
valve service port.
3. Measure suction temperature by attaching an accurate
thermistor type or electronic thermometer to suction line at
service valve.
4. Measure outdoor air dry-bulb temperature with thermom-
eter.
5. Measure indoor air (entering indoor coil) wet-bulb tempera-
ture with a sling psychrometer.
6. Refer to Table 3. Find outdoor temperature and evaporator
entering air wet-bulb temperature. At this intersection, note
superheat.
7. Refer to Table 4. Find superheat temperature located in item
6 and suction pressure. At this intersection, note suction line
temperature.
8. If unit has a higher suction line temperature than charted
temperature, add refrigerant until charted temperature is
reached.
9. If unit has a lower suction line temperature than charted
temperature, reclaim refrigerant until charted temperature is
reached.
10. If outdoor air temperature or pressure at suction valve
changes, charge to new suction line temperature indicated
on chart.
XIII.
FINAL CHECKS
IMPORTANT:
Before leaving job, be sure to do the following:
1. Securely fasten all panels and covers.
2. Tighten service valve stem caps to 1/12-turn past finger
tight.
3. Leave User’s Manual with owner. Explain system operation
and periodic maintenance requirements outlined in manual.
4. Fill out Dealer Installation Checklist and place in customer
file.
CARE AND MAINTENANCE
For continuing high performance and to minimize possible equip-
ment failure, periodic maintenance must be performed on this
equipment.
Frequency of maintenance may vary depending upon geographic
areas, such as coastal applications.
—5—
