Table of Contents
Advertisement
REFRIGERANT CHARGING
WARNING:
These units are shipped fully charged with
R-410A refrigerant and ready for installation.
When a system is installed according to these
instructions,no refrigerant charging is required.
If repairs make it necessary for evacuation and
charging, it should only be done by qualified,
trained personnel thoroughly familiar with this
equipment. Some local codes require licensed
installation/service personnel to service this
type of equipment. Under no circumstances
should the owner attempt to install and/or
service this equipment. Failure to comply with
this warning could result in property damage,
personal injury, or death.
CAUTION:
This unit uses R-410A refrigerant. DO NOT use
any other refrigerant in this unit. Use of another
refrigerant will damage the unit.
For charging in the field, the unit should be run with a call
for second stage cooling with both Y1 and Y2 outputs
energized. This may be accomplished by setting the
thermostat to cool with a setpoint substantially lower
than room temperature. This will provide 60 minutes of
operation at the nominal rating speed (interface board
display "C4") before there is a speed change (to a higher
speed- "C5"). If the speed change to "C5" occurs before
the charging process is complete, turn the system off, then
restart the process. Refer to the charge amount listed on
the units data label.
Alternate Procedure for Charging Air
Conditioner in Cooling Mode (with outdoor
temperatures above 60° F) based on
Subcooling
While charging based on refrigerant weight shown on
unit rating label is preferred, this method is acceptable.
Use this method when the outdoor temperature is 60 °
F or higher to verify the correct charge in cooling mode.
The indoor temperature should be between 70 ° F and
80° F.
1. Connect the gauge manifold to the liquid and vapor
service valves. See Figure 5 (page 10).
2. Start the system in cooling mode. Allow the system to
run 15 minutes to stabilize.
3. Record the liquid refrigerant pressure in psig at the
service valve.
4. Record the liquid refrigerant line temperature in °F at
the service valve.
36
5. Using the temperature value recorded, determine the
corresponding liquid refrigerant pressure from the curve
in the appropriate charging chart. See Figures 19 - 22
pages 37 & 38.
6. If the pressure measured in step 3 is less than the
required liquid refrigerant pressure determined in step
5, then refrigerant needs to be added.
7. If the pressure measured in step 3 is greater than the
required liquid refrigerant pressure determined in step
5, then the system is over-charged.
8. Add or remove charge from the system depending on the
measurements recorded. Allow the system to stabilize
for 15 minutes before taking the next readings.
Application Notes on the Use of Charging
Charts
This equipments cooling system contains refrigerant under
high pressure, always use safe practices when servicing
the unit. Always review the factory literature and safety
warnings prior to servicing.
These units are shipped from the factory with the proper
amount and type of refrigerant. Always inspect the unit
rating label to determine the units information prior to
working on the system. Do not mix different refrigerants
or charge the unit with a refrigerant not listed on the unit
rating label.
The charging charts (Figures 19 - 22 pages 37 & 38)
are valid for a variety of indoor, return air conditions
and are most highly influenced by the outdoor ambient
temperature, outdoor fan operation and the unit operating
voltage. Before referencing the charts, always make sure
that the compressor circuit is energized on nominal speed
(Y1 & Y2 energized) and has stable operation. As can be
seen in the charging charts, the ideal system sub-cooling
can vary over the range of operation. Always reference
the charts to determine the ideal amount of sub-cooling
for a given liquid pressure. Units charged to other values
will not perform at the rated unit efficiency (EER).
To inspect a systems operation, using quality instruments,
match the measured liquid temperature to the units chart.
The measured liquid pressure reading should be within
3% of the value shown for most installations.
DO NOT use the charts for operating under first stage
cooling.
For systems that are operating with more then a 5%
deviation, inspect the unit for leaks. Always use safe and
environmentally sound methods for refrigerant handling.
When repairing system leakages, always utilize a nitrogen
(inert) gas to protect the refrigerant system and pressure
check the repair before re-charging. Always replace the
filter-dryers when performing any repair to the refrigeration
system. After completing the repairs, evacuate the system
to 350-500 microns and weigh in the refrigerant to the
amount specified on the unit rating label.
Hide quick links:
Advertisement
Table of Contents
