Page 21
C − Charging SSB*H4S41Y through
SSB*H4S43Y
Charge Using the Weigh-in Method
Outdoor
Temperature < 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 Subcooling Method
Outdoor
Temperature < 65ºF (18ºC)
When the outdoor ambient temperature is below 65°F
(18°C), use the subcooling method to charge the unit. If
necessary, restrict the air flow through the outdoor coil to
achieve pressures in the 325−375 psig (2240−2585 kPa)
range. These higher pressures are necessary for checking
the charge. Block equal sections of air intake panels and
move obstructions sideways until the liquid pressure is in
the 325−375 psig (2240−2585 kPa) range. See figure 22.
Blocking Outdoor Coil
BLOCK OUTDOOR COIL ONE
SIDE AT A TIME WITH
CARDBOARD OR PLASTIC
SHEET UNTIL PROPER TESTING
PRESSURES ARE REACHED.
CARDBOARD OR PLASTIC
SHEET
FIGURE 22
1. With the manifold gauge hose still on the liquid service
port and the unit operating stably, use a digital ther-
mometer to check the liquid line temperature and re-
cord in table 2.
2. At the same time, record the liquid line pressure reading.
3. Use a temperature/pressure chart for HFC−410A (table
9) to determine the saturation temperature for the liquid
line pressure reading; record in table 2.
4. Subtract the liquid line temperature from the saturation
temperature (according to the chart) to determine the
subcooling value.
5. Compare the subcooling value with those in table 2. If
subcooling value is greater than shown, recover some
refrigerant; if less, add some refrigerant.
TABLE 2
SPB036H4 Subcooling Values for Charging
Second Stage (High-Capacity)
SSB*H4S41Y through SSB*H4S43Y
Saturation Temperature
Liquid Line Temperature
=
Subcooling Value
Model
SPB036H4S41
SPB048H4S41
SPB060H4S41
°F (°C)*
7 (3.9)
9 (5)
8 (4.4)
*F: +/−1.0°; C: +/−0.5°
Charge Using the Approach Method
Outdoor
Temperature > 65ºF (18ºC)
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. Check the outdoor ambient temperature using a digital
thermometer and record in table 3.
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
tables 4 and 5, Normal Operating Pressures." 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 sys-
tem. Pressures higher than those listed indicate that
the system is overcharged. Pressures lower than those
listed indicate that the system is undercharged. Contin-
ue to check adjusted charge using approach values.
4. Use the same digital thermometer used to check out-
door ambient temperature to check liquid line tempera-
ture and record in table 3. Verify the unit charge using
the approach method. The difference between the am-
bient and liquid temperatures should match values giv-
en in table 3. Add refrigerant to lower the approach tem-
perature and remove it to increase the approach tem-
perature. Loss of charge results in low capacity and ef-
ficiency.
5. If the values do not agree with those in table 3, add re-
frigerant to lower the approach temperature or recover
refrigerant from the system to increase the approach
temperature.
