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505095M 1/3/06
IMPORTANT
Charge adjustments may be required to allow for
longer line sets and coil volumes. Check for proper
charge using charging information in this manual.
5. Monitor the system to determine the amount of mois-
ture remaining in the oil. Use test kit 10N46 to verify
that the moisture content is within the kit’s dry color
range. It may be necessary to replace the filter drier
several times to achieve the required dryness level.
If
system dryness is not verified, the compressor
will fail in the future.
Checking Charge
The outdoor unit should be charged during warm weather.
However, applications arise in which charging must occur
in the colder months. The method of charging is deter-
mined by the outdoor ambient temperature.
Measure the liquid line temperature and the outdoor ambi-
ent temperature as outlined below:
1. Connect the manifold gauge set to the service valves:
D
low pressure gauge to
vapor
valve service port
D
high pressure gauge to
liquid
valve service port
Close manifold gauge set valves. Connect the center
manifold hose to an upright cylinder of R−410A .
2. Set the room thermostat to call for heat. This will
create the necessary load for properly charging the
system in the cooling cycle.
3. Record outdoor ambient temperature using a digital
thermometer.
4. When the heating demand has been satisfied, switch
the thermostat to cooling mode with a set point of 68ºF
(20ºC). When pressures have stabilized, use a digital
thermometer to record the liquid line temperature.
5. The outdoor temperature will determine which charg-
ing method to use. Proceed with the appropriate
charging procedure.
Charge Using Weigh-in Method
Outdoor Temper-
ature < 65ºF (18ºC)
If the system is void of refrigerant, or if the outdoor ambient
temperature is cool, first, locate and repair any leaks and
then weigh in the refrigerant charge into the unit.
1. Recover the refrigerant from the unit.
2. Conduct leak check; evacuate as previously outlined.
3. Weigh in the unit nameplate charge. If weighing facili-
ties are not available or if charging the unit during
warm weather, use one of the following procedures.
Charge Using the Approach Method
Outdoor
Temp. >65ºF (18ºC)
The following procedure is intended as a general guide and
is for use on expansion valve systems only. For best re-
sults, outdoor temperature should be 70°F (21°C) to 80°F
(26°C). Monitor system pressures while charging.
1. Record outdoor ambient temperature using a digital
thermometer.
2. Attach high pressure gauge set and operate unit for
several minutes to allow system pressures to stabilize.
3. Compare stabilized pressures with those provided in
table 5, Normal Operating Pressures." Minor varia-
tions in these pressures may be expected due to differ-
ences in installations. Significant differences could
mean that the system is not properly charged or that
a problem exists with some component in the system.
Pressures higher than those listed indicate that the
system is overcharged. Pressures lower than those
listed indicate that the system is undercharged. Con-
tinue to check adjusted charge using approach values.
4. Use the same digital thermometer you used to check
the outdoor ambient temperature to check the liquid
line temperature.
5. The difference between the ambient and liquid tem-
peratures should match values given in table 4. If the
values do not agree with the those in table 4, add re-
frigerant to lower the approach temperature, or recov-
er refrigerant from the system to increase the ap-
proach temperature.
Table 4
XC15 Approach Values
_
Liquid Line Temperature
_
Outdoor Temperature
=
_
Approach Temperature
Model
−024
−030
−036
−042
−048
−060
°F
(°C)*
10
(5.6)
12
(6.7)
11
(6.1)
13
(7.2)
6
(3.3)
10
(5.6)
NOTE − For best results, use the same electronic thermometer to
check both outdoor-ambient and liquid-line temperatures.
*F: +/−1.0°; C: +/−0.5°
NOTES −
S
R−410A refrigerant cylinders are rose−colored. Refrig-
erant should be added through the vapor valve in the
liquid state.
S
Certain R−410A cylinders are identified as being
equipped with a dip tube. These allow liquid refrigerant
to be drawn from the bottom of the cylinder without in-
verting the cylinder. DO NOT turn this type cylinder up-
side−down to draw refrigerant.
