Plumbing - Lennox HS29-072 Installation Instructions Manual

Plumbing

Field refrigerant piping consists of liquid and suction lines
exiting the condensing unit. You may bring piping into the
unit through either side. Remove the knockouts on the mul
lions and install the provided rubber grommets into the pip
ing holes. Remove the plugs from the liquid and suction
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 for Runs Up to 50 Linear Feet
Unit Liquid Line
5/8 in.
HS29−072
(16 mm)
5/8 in.
HS29−090
(16 mm)
5/8 in.
HS29−120
(16 mm)
Refrigerant Line Brazing Procedure
1 − Cut the end of the refrigerant line square, keep it round,
protect it from nicks or dents, and debur it. (I.D. and
O.D.)
2 − Wrap a wet cloth around the liquid and suction valve
body when brazing to prevent possible heat damage to
the valve core and port.
3 − In the liquid line, install the filter drier (provided with the
unit) in an accessible area as close as possible to the
expansion device.
Refrigerant Line Limitations
You may install the unit in applications that have line set
lengths of up to 50 linear feet (15 m) with refrigerant line
sizes as outlined in table 1 (excluding equivalent length of
fittings). Size refrigerant lines from 50 to 100 linear feet (15
to 30 m) according to the the following section. Line lengths
greater than 100 feet (30 m) are not recommended.
Maximum suction lift must not exceed 70 linear feet (21 m)
and the maximum liquid head must not exceed 50 linear
feet (15 m).
Temp. Pressure
°F (°C) psig (kPa)
−40 (−41) 0.6 (4.13)
−30 (−34) 4.09 (28.1)
−20 (−28) 10.2 (70.3)
−10 (−23) 16.6 (114)
0 (−18) 24.1 (166)
10 (−12) 32.9 (227)
12 (−11) 34.9 (241)
14 (−10) 36.9 (254)
16 (−9) 39.0 (269)
Suction Line
1−1/8 in.
(29 mm)
1−3/8 in.
(35 mm)
1−3/8 in.
(35 mm)
HCFC 22 Saturation Temperatures
(Condensing Temperatures at Different Pressures)
Temp. Pressure Temp.
°F (°C) psig (kPa) °F (°C)
18 (−8) 41.1 (283) 36 (2)
20 (−7) 43.3 (299) 38 (3)
22 (−6) 45.5 (314) 40 (4)
24 (−4) 47.9 (330) 45 (7)
26 (−3) 50.3 (347) 50 (10)
28 (−2) 52.7 (363) 55 (13)
30 (−1) 55.2 (381) 60 (16)
32 (0) 57.8 (399) 65 (18)
34 (1) 60.5 (417) 70 (21)
When line lengths exceed 50 feet (15 m), install a liquid line
solenoid at the evaporator coil. In addition, use only expan
sion valves (RFC and cap tube expansion devices are not
acceptable).
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.
Because additional refrigerant is necessary to fill the lines,
the likelihood of slugging is greatly increased if the lines are
over 50 feet (15 m). An incremental increase in liquid line
size results in a 40 to 50 percent increase in liquid refriger
ant to fill the line. Therefore, use the smallest liquid line size
possible.
All units are equipped with a low ambient (head pressure)
control to allow for cooling at an ambient condition of 0°F
(−18°C).
Pipe Sizing, Line Layout, and Design
[Line Set Lengths of 50 − 100 Linear Feet
(15 − 30 m)]
Create a a sketch of the system that shows the relative
locations of the condensing unit and the evaporator as well
as the length of the following:
each piping segment
D
elbows
D
tees
D
valves
D
Use this information to determine the equivalent length of
the piping run. Also, take note of any difference in the
elevation between the outdoor and indoor units. You must
consider vapor and liquid lift so that you can properly size
the pipe.
Liquid Line Function and Design
The liquid line must convey a full column of liquid from the
condenser to the metering device at the evaporator coil
without flashing. In order to ensure this, you must consider
the liquid line pressure drop and the pressure across the
expansion device and distributor.
Table 2
Pressure Temp.
psig (kPa) °F (°C)
63.3 (436) 75 (24)
66.1 (456) 80 (27)
69.0 (476) 85 (29)
76.6 (528) 90 (32)
84.7 (584) 95 (35)
93.3 (643) 100 (38)
102.4 (706) 105 (41)
112.2 (774) 110 (43)
122.5 (841) 115 (46)
Page 10
Pressure Temp.
psig (kPa) °F (°C)
133.4 (920) 120 (49)
145.0 (1000) 125 (52)
157.2 (1084) 130 (54)
170.0 (1172) 135 (57)
183.6 (1287) 140 (60)
197.9 (1364) 145 (63)
212.9 (1468) 150 (66)
228.6 (1576) 155 (68)
245.2 (1691) 160 (71)
Pressure
psig (kPa)
262.5 (1810)
280.7 (1936)
299.7 (2066)
319.6 (1514)
340.3 (2346)
362.0 (2496)
384.6 (2651)
406.3 (2801)
433.3 (2987)