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Table 2—Wind Baffle Dimensions for WeatherMaker™ Units with Star-Burst Top (In.)
UNIT SIZE
AA
UNIT HEIGHT
21-7/8
Small
27-1/2
25-7/8
31-7/8
25-7/8
Medium
34-15/16
31-7/8
37-7/8
31-7/8
Large
45
37-7/8
Table 3—Wind Baffle Dimensions for WeatherMaker™ Units with Silencer System™ Top (In.)
UNIT SIZE
AA
UNIT HEIGHT
23-13/16
Small
27-1/2
27-13/16
33-13/16
27-13/16
Medium
34-15/16
33-13/16
39-13/16
33-13/16
Large
45
39-13/16
Step 3—Metering Device Sizing
The metering device for a long-line application must be flexible
enough to compensate for frictional losses due to long refrigerant
lines and installed system design (indoor coil above or below
outdoor unit.) The piston or TXV provides such flexibility.
The piston should be changed for both indoor coil and outdoor heat
pump unit, depending on system configuration and line length.
Tables 7 and 8 provide necessary changes for a given application.
Use Tables 7 and 8 when selecting correct piston size. Outdoor-
unit presale literature must be consulted to determine metering
devices specified for standard applications. After determining
standard application piston size(s), refer to Tables 7 and 8 as they
relate to system design (outdoor unit above or below indoor unit)
per equivalent length of tubing.
NOTE: If total equivalent horizontal length is 100 ft or longer,
both indoor and outdoor pistons must be increased 1 full piston
size, in addition to changes required by Tables 7 and 8.
After finding appropriate change in piston size, add or subtract the
change from original piston number. If piston size is decreased,
round new piston number down to nearest common piston number
found in Table 9. If piston size is increased, round new piston
number up to nearest common piston number found in Table 9.
A
B
C
D
17
25-1/4
10-3/8
19-3/4 20-1/2
17
25-1/4
10-3/8
23-3/4 24-1/2
17
25-1/4
10-3/8
29-3/4 30-1/2
21
32
11-3/16 23-3/4 24-1/2
21
32
11-3/16 29-3/4 30-1/2
21
32
11-3/16 35-3/4 36-1/2
25-3/16
42
12-15/16 29-3/4 30-1/2 50-7/16 29-11/16 30-7/16 29-5/8 22-11/16 14-7/8 7-1/16
25-3/16
42
15-15/16 35-3/4 36-1/2 50-7/16 35-11/16 36-7/16 35-5/8 22-11/16 17-7/8 7-1/16
A
B
C
D
17
25-1/4
10-3/8
19-3/4 20-1/2
17
25-1/4
10-3/8
23-3/4 24-1/2
17
25-1/4
10-3/8
29-3/4 30-1/2
21
32
11-3/16 23-3/4 24-1/2
21
32
11-3/16 29-3/4 30-1/2
21
32
11-3/16 35-3/4 36-1/2
25-3/16
42
12-15/16 29-3/4 30-1/2 50-7/16 29-11/16 30-7/16 29-5/8 22-11/16 14-7/8 7-1/16
25-3/16
42
15-15/16 35-3/4 36-1/2 50-7/16 35-11/16 36-7/16 35-5/8 22-11/16 17-7/8 7-1/16
E
F
G
34
19-11/16 20-7/16 19-5/8
34
23-11/16 24-7/16 23-5/8
34
29-11/16 30-7/16 29-5/8
42
23-11/16 24-7/16 23-5/8 19-11/16 11-7/8 6-11/16
42
29-11/16 30-7/16 29-5/8 19-11/16 14-7/8 6-11/16
42
35-11/16 36-7/16 35-5/8 19-11/16 17-7/8 6-11/16
E
F
G.
34
19-11/16 20-7/16 19-5/8
34
23-11/16 24-7/16 23-5/8
34
29-11/16 30-7/16 29-5/8
42
23-11/16 24-7/16 23-5/8 19-11/16 11-7/8 6-11/16
42
29-11/16 30-7/16 29-5/8 19-11/16 14-7/8 6-11/16
42
35-11/16 36-7/16 35-5/8 19-11/16 17-7/8 6-11/16
EXAMPLE:
An 042 size heat pump is 75 ft above an 042 size fan coil.
The 042 size heat-pump presale literature specifies a size
80 indoor piston and size 63 outdoor piston.
To establish correct indoor piston size for a 75 ft vertical
separation, refer to Table 7. For a 75 ft equivalent line
length, the piston change is -5. Therefore subtract 5 from
the original indoor piston size of 80:
80 – 5 = 75
Table 9 provides common piston sizes. In this instance, 75
is not listed, therefore round DOWN to next piston size,
which would be 74.
To establish correct outdoor piston size for a 75 ft vertical
separation, refer to Table 8. For a 75 ft equivalent line
length, the piston change is +4. Therefore add 4 to the
original outdoor piston size of 63:
63 + 4 = 67
Since 67 is listed in Table 9, that is the piston which should
be used. If a 67 size piston were not listed, it would be
necessary to round UP to next piston size.
TXVs may be used instead of pistons for indoor-metering devices.
Some fan coils are equipped with a hard-shutoff, bi-flow TXV
standard, and no change is required. When sizing an accessory
TXV for long-line applications, TXV should be the same nominal
tonnage as outdoor unit. Refer to presale literature for kit part
numbers.
Step 4—Liquid-Line Solenoid And Tubing Configuration
There are 2 types of liquid-line solenoids: 1 for single-flow
applications and the other for bi-flow applications. The purpose of
having 2 solenoids is to minimize the valve internal-pressure drop
in accordance with refrigerant flow direction and liquid migration
to the compressor. The bi-flow solenoid is designed to have
minimal refrigerant-pressure drop in either flow direction, which
makes it suitable for heat pump usage. Refer to Table 10 for
liquid-line solenoid kit part numbers.
NOTE: When installing a liquid-line solenoid, the system may
require a minimum 60-va low-voltage transformer.
5
H
J
K
L
0
0
0
11-7/8
0
14-7/8
H.
J
K
L
0
0
0
11-7/8
0
14-7/8
M
6-1/8
6-1/8
6-1/8
M
6-1/8
6-1/8
6-1/8
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