Subcooling Calculation - Rheem PNL-*AZ Series Installation Instructions Manual

TABLE 10
TEMPERATURE PRESSURE CHART
TEMP R-410A
(Deg. F)
-150
-140
-130
-120
-110
-100
-90
-80
-70
-60
-50
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
35 107.5
40 118.5
45 130.2
50 142.7
55 156.0
60 170.1
65 185.1
70 201.0
75 217.8
80 235.6
85 254.5
90 274.3
95 295.3
100 317.4
105 340.6
110 365.1
115 390.9
120 418.0
125 446.5
130 476.5
135 508.0
140 541.2
145 576.0
150 612.8
24

15.5 SUBCOOLING CALCULATION

1. Measure the liquid pressure at the liquid line service valve.
2. Convert the liquid line pressure to saturated temperature. See Table 10.
PSIG
3. Measure the liquid line temperature at the liquid line service valve.
—
4. Compare the liquid line temperature to the saturated temperature.
—
5. The difference between saturated temperature and liquid line temperature is the
—
subcooling. Subcooling normal range 9° to 12°.
—
NOTE: The subcooling charging method should only be used in the cooling mode
—
as the heating subcooling design level varies widely from one unit to the next while
—
the cooling subcooling design level is fairly consistent at 8-12 degrees.
—
—
—
0.4
5.1
10.9
14.2
17.9
TABLE 11
22.0
HEAT PUMP SYSTEM TROUBLESHOOTING TIPS
26.4
31.3
36.5
SYSTEM PROBLEM
42.2
48.4
55.1
62.4
Liquid Restriction (Drier)
70.2
Low Evaporator Airflow
78.5
87.5
Low Outside Ambient Temperature
97.2
Inefficient Compressor
TEV Feeler Bulb Charge Lost
Poorly Insulated Sensing Bulb
HEAT PUMP SYSTEM
TROUBLESHOOTING TIPS
DISCHARGE
PRESSURE PRESSURE
Overcharge High
Undercharge Low
Low
Low
Dirty Heat Pump High
Low
Low
Low
High
INDICATORS
SUCTION
SUPERHEAT SUBCOOLING
High Low High
Low High Low
Low High High
Low Low Low
High Low Low
Low High High
High High High
Low High High
High Low Low
COMPRESSOR
AMPS
High
Low
Low
Low
High
Low
Low
Low
High