Temp.
(°F)
Pressure
(psig)
20
78.4
22
81.9
24
85.5
26
89.2
28
93.1
30
97.0
32
101
34
105
36
109
38
114
40
118
42
123
44
128
46
133
48
137
50
143
55
155
60
170
65
185
70
201
Temp.
(°F)
Pressure
(psig)
75
218
80
236
85
255
90
274
95
295
100
318
105
341
110
365
115
391
120
418
125
446
130
477
135
508
140
541
CyberAiR DX Floor Mounted IOM Manual
2.9.5.2
-30°F Ambient Applications
For units designed for -30°F operation, a receiver is
used to store the refrigerant during the time the
condenser is not utilizing the extra refrigerant
charge.
1. Follow steps 1 - 8 in Section 2.9.5. Once
superheat and sub-cooling temperatures are
stabilized, additional refrigerant must be added to
the receiver.
It is important not to exceed 80% of the total
condenser and receiver volume to allow room for
expansion.
2. The head pressure control valve setting is printed
on the side of the valve body. This setting is the
lowest head pressure that will be maintained
during system operation. It may be necessary to
add additional refrigerant to raise the head
pressure to the value printed on the valve (290
psig for R-410A).
3. If a refrigerant level sight glass is included on
the side of the receiver, it may be used to
assist in charging the air conditioning system.
The proper charge can be confirmed by
viewing the level
of refrigerant in the receiver(s) while the unit is
running at an elevated discharge pressure.
4. Keep the air intake to the condenser blocked
and maintain the discharge pressure at 445
psig and hold it constant. The condenser fan
nearest the condenser header should be
operating
continuously. All other fans, if additional fans
exist, should be off during this time.
5. Add additional refrigerant charge to the receiver
as needed until the refrigerant level rises to the
center of the sight glass, indicating the receiver
is 80% filled.
When the refrigerant in the receiver reaches the
sight glass, the unit is fully charged.
CAUTION
Remove the blockage from the air intake of the
condenser.
6. Fill out the applicable sections of the Warranty
Registration and Start-Up Checklist.
2.9.6 Refrigerant Characteristics
2.9.6.1
Pressure/Temperature Settings
The following table is provided to assist with the normal
settings of the system for R-410A refrigerant. Where
applicable, minimum and maximum settings are given along
with normal operating pressure.
R-410A Refrigerant Pressure/Temperature Settings
Sub-cooling °F
Normal Min.
10
5
Max.
20
Superheat °F
15
10
20
Design Condensing Temp. @ 95°F
Ambient
125
105
140
Suction Pressure (psig)-
130
105
155
2.9.6.2
Saturated Refrigerant Pressure
This refrigerant temperature/pressure table is
provided for reference for R-410A refrigerant.
R-410A Refrigerant Pressures
2.9.4
Settings and Adjustments
2.9.5
Low/High Pressure Limit Switch
Air conditioning systems utilizing DX refrigerant
are equipped with hermetically sealed high-
pressure and low-pressure switches. These
switches are pre-set and cannot be adjusted. The
high- pressure switch opens at 630 psig and has a
manual reset. The low-pressure switch opens at 65
psig (± 10) and closes at 105 psig (± 10) and has
an automatic reset.
2-22
