22
RT-SVF69C-EN
Subcooling Charging Curves
To Check Subcooling
1.
System must be running at stabilized conditions
before measuring sub-cooling and superheat.
2. Do not add refrigerant if the superheat is less than 5°F.
3. Refrigerant charge adjustment:
a. ADD charge if the sub-cooling is more than 5°F
below curve value.
b. REDUCE charge if the sub-cooling is more than 5°F
above curve value.
c. OK if the sub-cooling is within 5°F of the curve
value.
4. The standard superheat operating range for units with
the standard offering thermal expansion valves is 16°F
- 24°F. These superheat operating ranges are
acceptable when used in conjunction with the
provided pressure and sub cooling curves.
Figure 3.
T/YZ*150 Charging Curve
100
150
200
250
300
350
400
450
500
550
600
45
55
65
75
85
95
105
115
125
135
Liquid Pressure
Leav
ing OD Coil,
psig
Liquid Temperature Leaving OD Coil, °F
Fixed system
VS system
Remove charge
Add charge
Both Compressors Running