Table of Contents
Advertisement
Plumbing
Field refrigerant piping consists of liquid and vapor lines
from the heat pump unit. Piping may be brought into the
unit through either side. Remove the knockouts on the
mullions and install the provided rubber grommets into the
piping holes. Remove the plugs from the liquid and vapor
lines. Refer to table 1 for field fabricated refrigerant line
sizes for runs up to 50 linear feet (15 m).
TABLE 1
REFRIGERANT LINE SIZES
UNIT
LIQUID LINE
HP29-090
5/8 in. (16 mm)
HP29-120
5/8 in. (16 mm)
Refrigerant Line Brazing Procedure
1 - End of refrigerant line must be cut square, kept round,
free from nicks or dents and deburred (I.D. and O.D.)
2 - Wrap a wet cloth around the valve body when brazing
to prevent possible heat damage to the valve core and
port.
3 - Install filter drier, provided with unit, in the liquid line as
close as possible to the expansion device.
Refrigerant Line Limitations
Unit applications with line set lengths up to 50 linear feet
(15 m) (excluding equivalent length of fittings) may be
installed using refrigerant line sizes as outlined in table 1.
Refrigerant lines from 50 to 100 linear feet (15 to 30 m)
should be sized in accordance with the following sec
tion. The maximum line length is 100 feet (30 m).
Maximum suction rise must not exceed 45 linear feet
(13.7 m) and maximum liquid head must not exceed 45
linear feet (13.7 m).
Degrees F (°C)
HCFC22
Degrees F (°C)
-40 (-41)
0.6
-30 (-34)
4.9
-20 (-28)
10.2
-10 (-23)
16.6
0 (-18)
24.1
10 (-12)
32.9
12 (-11)
34.9
14 (-10)
36.9
16 (-9)
39.0
VAPOR LINE
1-3/8 in. (35 mm)
1-3/8 in. (35 mm)
HCFC 22 SATURATION TEMPERATURES
(Condensing Temperatures at Different Pressures)
HCFC 22 Pressure Temperature Table (Psig)
HCFC22
Degrees F (°C)
18 (-8)
41.1
36 (2)
20 (-7)
43.3
38 (3)
22 (-6)
45.5
40 (4)
24 (-4)
47.9
45 (7)
26 (-3)
50.3
50 (10)
28 (-2)
52.7
55 (13)
30 (-1)
55.2
60 (16)
32 (0)
57.8
65 (18)
34 (1)
60.5
70 (21)
Refer to the refrigerant piping guideline manual (Corp.
9351-L9) if line lengths exceed 50 feet (15 m). In these
applications, you must install a liquid line solenoid valve
at the evaporator coil. In addition, use expansion valves
only (RFC and cap tube expansion devices are not ac
ceptable). In applications where the lines exceed 75 feet
(23 m), install the solenoid valve with a non recycling
pump down control.
NOTE - When refrigerant line solenoid valves are installed,
velocities should not exceed 300 fpm (1.5 m/s) in order to
avoid liquid line hammer.
All units are equipped with a low ambient (head pressure)
control to allow for cooling down to 0°F (-18°C).
Due to the additional refrigerant required to fill the lines,
the likelihood of slugging is greatly increased with lines
that are over 50 feet (15 m) in length. An incremental in
crease in liquid line size results in a 40 to 50 percent in
crease in liquid to fill the line. Therefore, it is desirable to
use the smallest liquid line size possible.
Pipe Sizing, Line Layout and Design
[Line set lengths from 50 - 100 linear feet
(15 - 30 m)]
Start by making a sketch of the system showing relative
locations of the heat pump unit and the indoor coil, length of
each piping segment, elbows, tees, valves, etc. This infor
mation will be used to determine the equivalent length of
the piping run. Also, take note of any difference in elevation
between the outdoor and indoor units. Vapor and liquid lift
must be considered to ensure proper pipe sizing.
Liquid Line Function and Design
The liquid line must convey a full column of liquid from the
outdoor unit to the metering device at the indoor coil with
out flashing. In order to ensure this, liquid line pressure
drop and pressure across the expansion device and dis
tributor must be considered.
TABLE 2
HCFC22
Degrees F (°C)
63.3
75 (24)
66.1
80 (27)
69.0
85 (29)
76.6
90 (32)
84.7
95 (35)
93.3
100 (38)
102.4
105 (41)
112.2
110 (43)
122.5
115 (46)
Page 10
HCFC22
Degrees F (°C)
HCFC22
133.4
120 (49)
262.5
145.0
125 (52)
280.7
157.2
130 (54)
299.7
170.0
135 (57)
319.6
183.6
140 (60)
340.3
197.9
145 (63)
362.0
212.9
150 (66)
384.6
228.6
155 (68)
406.3
245.2
160 (71)
433.3
Advertisement
Table of Contents
