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will be light maroon−colored. Refrigerant should be
added through the vapor line valve in the liquid state.
Some R410A cylinders are equipped with a dip
tube that allows you to draw liquid refrigerant from
the bottom of the cylinder without turning the cyl-
inder upside−down. The cylinder will be marked if it
is equipped with a dip tube.
Table 3
Subcooling Values for Charging
Model Number
Subcooling Values
Conversion Temp. − Liquid Line Temp.
°
F (
°
C)
HPXA15−024
5 ± 1 (2.8 ± .5)
HPXA15−030
8± 1 (7.4 ± .5)
HPXA15−036
5.5 ± 1 (3 ± .5)
HPXA15−042
4.5 ± 1 (2.5 ± .5)
HPXA15−048
2.5 ± 1 (1.4 ± .5)
HPXA15−060
6 ± 1 (3.3 ± .5)
Charging Using Normal Operating Pressures
and the Approach Method
Outdoor Temp. > 65
F (18
C)
The following procedure is intended as a general guide and
is for use on expansion valve systems only. For best results,
indoor 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. Verify
adjusted charge using the approach method.
Approach Method
4 − Use the same digital thermometer used to check out-
door ambient temperature to check liquid line tempera-
ture. Verify the unit charge using the approach method.
5 − The difference between the ambient and liquid temper-
atures should match values given in table 4. If the val-
ues don’t agree with the those in table 4, add refriger-
ant to lower the approach temperature or recover
refrigerant from the system to increase the approach
temperature.
Table 4
Approach Values for Charging
Model Number
Approach Temperature
Liquid Line Temp. − Outdoor Ambient °F (°C)
HPXA15−024
13 ± 1 (7.2 ± .5)
HPXA15−030
7 ± 1 (3.9 ± .5)
HPXA15−036
11 ± 1 (6.1 ± .5)
HPXA15−042
12.5 ± 1 (6.9 ± .5)
HPXA15−048
10 ± 1 (5.6 ± .5)
HPXA15−060
11.5 ± 1 (6.5 ± .5)
IMPORTANT
Use table 5 as a general guide when performing
maintenance checks. This is not a procedure for
charging the unit (Refer to Charging/Checking
Charge section). Minor variations in these pressures
may be expected due to differences in installations.
Significant differences could mean that the system
is not properly charged or that a problem exists with
some component in the system.
