User Manual

YMGI, Engineered Comfort Products for A Sustainable and Efficient Green World!
39
SYSTEM INSPECTION AND TRIAL RUNNING
CHECK SYSTEM THOROUGHLY
Check system thoroughly to make sure the unit is ready for trial running:
check wires and pipes and air intake and discharge and power and
thermostat and others necessary components.
ADJUST REFRIGERANTGUIDELINE
Right amount of refrigerant is very important. It is one of the basics to
ensure a safe operation over time.
Normally single zone outdoor unit is pre-charged with refrigerant for 25ft
inter-connecting copper (liquid) line.
Multiple zone outdoor unit is pre-charged for various length of copper
(liquid) lines of allowed quantity of indoor units, following specs or
engineering submittal.
For single zone unit or multiple zone multiple compressor unit, normally
the outdoor unit is pre-charged for 25ft line sets. If the copper line is
longer or shorter than 25ft, need to add or deduct refrigerant, following
general rule of thumb for rough adjustment: 1/4" liquid line unit: 0.3 Oz/ft;
3/8" liquid line unit: 0.4 OZ/ft.; 1/2" liquid line unit: 1.2 OZ/ft.
For multiple zone one compressor unit, if the copper line is longer or
shorter than the length at which pre-charged refrigerant is good for, as
listed in the engineering submittal or related labels or tables, need to add
or deduct refrigerant, following 0.23 OZ/ft. rule of thumb for rough
adjustment.
In all situations, the minimum copper line (liquid or gas) length for each
indoor unit is 15ft.
For a better adjustment, may combine above guideline with the indoor or
outdoor (ambient) temperature-refrigerant pressure chart, or generally 8-
12F super-heat method.
PRESSURE CHECKING
System pressure checking should be a must-do job during trial running of initial installation, and compressor/refrigerant-related troubleshooting.
It is a more accurate refrigerant adjusting method than rough refrigerant addition or deduction guideline shown above.
In some cases, if the service valve on unit is 5/16” and your service valve connection is 1/4”, need to use a 5/16”-1/4” adaptor so that you can
connect to your manifold. Need to pay attention to use the right manifold that is rated for the refrigerant in the unit, and pay attention to connect to the
right hose (blue hose for low pressure, red hose for high pressure, yellow hose for vacuum or charging or deduction). Not recommended to put hose
onto service valve while compressor is running. Remove hose quickly and carefully to avoid air suck-in, refrigerant leakage, or any refrigerant-freezing
burn.
The following curves are only reference for system pressure checking. Actual pressures may vary upon many factors such as inter-connecting pipe
length, refrigerant charge / leakage level, elevation difference between indoor unit and outdoor unit, tool calibration, reading error, and so on.
SYSTEM INSPECTION AND TRIAL RUNNING
Reference Temperature-Pressure Table (Split Condensing Unit-R410A AC)
Product Series: YMGI Group-Mini Split Version: 01/11/2010
Outdoor Dry-Bulb (F)
15
25
35
50
55
60
67
75
82
90
95
100
105
110
115
Outdoor Dry-Bulb (C)
-9.4
-3.9
1.7
10.0
12.8
15.6
19.4
23.9
27.8
32.2
35.0
37.
40.6
43.3
46.1
Outdoor Wet-Bulb (F)
13.6
23.0
30.2
42.8
46.9
51.1
59.5
66.6
64.9
71.2
75.0
79.0
82.9
86.9
90.7
Outdoor Wet-Bulb (C)
-10.2
-5
-1.0
6.0
8.3
10.6
15.3
19.2
18.3
21.8
23.9
26.1
28.3
30.5
32.6
Indoor Dry-Bulb
80F (26.7C)
Indoor Wet-Bulb
67F (19.4C)
Discharge-PSI/F
74/21.2
84/27.1
105/35.1
115/38.5
125/42.8
130/45.5
140/48.2
146/51.2
156/54.3
166/57.5
175/61.2
180/62.5
186/63.7
189/64.5
191/64.9
Suction-PSI/F
60/46.2
70/53.5
85/55.2
92/55.7
98/56.1
103/56.7
110/56.9
115/57.1
120/57.5
128/57.8
135/57.9
136/58.6
137/59.1
139/59.3
140/59.5
Suggest to Add on Low Ambient Control. If Still in Need
of AC for Long Time in Cold Weather.
Closely Check/Watch Refrigerant Charge Level
Warning: R410A refrigerant bears higher pressures than R22.
Only handled by Licensed HVAC technician.
Reference Temperature-Pressure Table (Split Condensing Unit, R410A-Heat Pump)
Product Series: YMGI Group-Mini Split System Version: 01/11/2010
Outdoor Dry-Bulb (F)
0
5
10
17
25
30
35
40
45
47
55
62