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Manual 2100-346
Page 15
PRESSURE SERVICE PORTS
High and low pressure service ports are installed on all units
so that the system operating pressures can be observed.
Pressure tables can be found later in the manual covering all
models. It is imperative to match the correct pressure table
to the unit by model number.
SYSTEM START-UP (INDOOR UNITS
WITHOUT EXPANSION VALVES)
1. Close disconnect switch(es) and set the thermostat to
cool and the temperature to the highest setting.
2. Check for proper airflow across the indoor coil by
referring to indoor unit installation.
3. Connect the service gauges and allow the unit to run for
at least 10 minutes or until pressures are stable. Check
pressures to the system pressure table attached to the
outdoor unit service panel. For optimum system
performance, go to Step 4.
4. Install a thermometer on the suction line approximately
6" to 10" from the compressor. Optimum system
performance will occur with a refrigerant charge
resulting in a suction line superheat as determined from
the following calculations.
A. Measure outdoor air dry bulb temperature
________ ºF
B. Measure indoor air wet bulb temperature
________ ºF
C. Measure suction pressure ______ PSIG
D. Measure suction line temperature ________ ºF
E. Determine optimum system superheat
from Table 9 using outdoor air dry bulb
(Step B) and indoor air wet bulb (Step A)
________ ºF
F. Determine saturated suction temperature
from suction pressure using Table 10 ________ ºF
G. Determine system superheat:
Suction line temperature (Step D) ________ ºF
- Saturated suction temperature (Step F)
- ________ ºF
= System superheat
= ________ ºF
H. Adjust the system superheat (Step G) to the
optimum system superheat (Step E) by adding
charge to lower the superheat or removing
charge to raise the superheat.
I. Check final system operating pressures to the
system pressure tables as was done in Step 3.
CHARGING INSTRUCTIONS
TABLE 9
SYSTEM SUPERHEAT
tneibmAroodtuO
F(erutarepmeT
)bluByrD
erutarepmeTriAnruteR
bluBteWF
95367617
501
59
09
58
08
57
1
1
1
3
8
01
1
3
7
9
41
02
5
)8(
41
91
52
03
02
62
33
93
24
TABLE 10
SATURATED SUCTION TEMPERATURE R-22
GISPerusserPnoitcuS
noitcuSdetarutaS
)F(erutarepmeT
05
35
55
62
82
03
85
16
36
23
43
63
56
76
07
83
93
14
37
67
97
34
54
74
28
68
94
15