CATALOGUE 201ME JANUARY 2004

CATALOGUE 201ME — Page 43
HEAD PRESSURE CONTROL VALVES
Condenser
Condenser
LAC
OROA
Check Valve
Compressor
Receiver
Compressor
Receiver
Figure 2 Figure 3
CAPACITIES — Ratings for the common refrigerants are given at
several pressure drops for the ORI’s, OROA, and LAC below.
Maximum capacities for the ORD-4 are given below also. Normally,
a 0.14 bar pressure drop across the ORI or OROA is recommended;
however, for most applications this can be exceeded, provided the
total pressure drop through the condenser and ORI or OROA does
not exceed 0.96 bar.
Therefore, to select either valve combination, it is necessary to know
the system capacity and refrigerant, the approximate pressure drop
through the condenser, the desired pressure setting for the OROA-5 or
LAC and the connections necessary. The standard pressure settings for
the OROA, and LAC are 6.90 bar for Refrigerant 134a and 12.41 bar
for Refrigerants 22 and 502. Other pressure settings are available on
special order. The ORI, OROA, and LAC connection size should be at
least the same size as the outlet on the condenser where possible.
Oversizing these valves is not harmful.
On large systems these valves can be applied in parallel.
Figure 4
NON-ADJUSTABLE VALVE TYPES
Capacities based on 38°C liquid temperature and 5°C evaporator temperature.
LIQUID FLOW CAPACITIES - kW
VALVE TYPE
PRESSURE
DROP
– bar
REFRIGERANT
22
and 401A
134a
402A
and 404A
407C
502 and 507
0.1
46
42
30
42
29
OROA-5
0.2
64
60
42
59
41
0.3
78
73
51
72
50
0.4
90
84
59
83
58
LAC Capacities listed below are calculated at high ambient (summer) conditions. The low ambient (winter) capacities should also be
considered when selecting these valves.
0.1
11
10
7 10
7
LAC-4
LAC-4-DS
0.2
16
15
10
14
10
0.3
19
18
12
17
12
0.4
22
20
14
20
14
0.1
24
22
16
22
15
LAC-5
0.2
34
32
22
31
22
0.3
42
39
27
38
27
0.4
48
45
31
44
31
0.1
51
47
33
46
33
LAC-10
0.2
71
66
46
65
45
0.3
85
79
56
78
55
0.4
98
91
64
90
63
For complete information refer to Bulletin 90-30 and 90-30-2.