17
REFRIGERANT LINES
General refrigerant line sizing:
1 The outdoor units are shipped with a full charge of R410A
refrigerant. All charges, line sizing, and capacities are based
on runs of 25 ft. (7.6 m). For runs over 25 ft. (7.6 m), refer
to the
Residential Long Line Guide
.
2 Minimum refrigerant line length between the indoor and
outdoor units is 10 ft. (3 m).
3 Refrigerant lines should not be buried in the ground. If it is
necessary to bury the lines, not more than 36--in (914 mm)
should be buried. Provide a minimum 6--in (152 mm) vertical
rise to the service valves to prevent refrigerant migration.
4 Both lines must be insulated. Use a minimum of 1/2--in.
(12.7 mm) thick insulation. Closed--cell insulation is
recommended in all long--line applications.
5 Special consideration should be given to isolating
interconnecting tubing from the building structure. Isolate the
tubing so that vibration or noise does not transmit into the
structure.
IMPORTANT:
Both refrigerant lines must be insulated
separately.
S
The following maximum lengths are allowed:
Table 13 – Maximum Refrigerant Line Lengths
Unit Size
Max Line
Length* ft(m
Max Elevation
(ID over OD)
ft ( m)
Max
Elevation (OD
over ID) ft (m)
18K-34K
250 (76.2)
65 (19.8)
200 (61)
Note
:
For lengths greater than 25 ft. (7.6 m), refer to the
Residential
Long Line Guide
.
*Maximum actual length not to exceed 200 ft. (61 m). Total equivalent
length accounts for losses due to elbows or fitting. See the
Long Line
Guideline
for details.
S
The following are the piping sizes.
Table 14 – Pipe Sizes
Indoor Unit
Outdoor Unit
Indoor Unit Tube
Sizes (in)
TXV Kit Tube
Sizes (in)
Outdoor Unit
Tube Size (in)
Liquid
Vapor
Liquid
Vapor
Liquid
Vapor
40MKCB18C----3
24AHA418
124ANS018
3/8
5/8
3/8
5/8
3/8
5/8
40MKCB34C----3
24AHA424
124ANS024
3/4
3/4
3/4
40MKCB34C----3
24AHA430
124ANS030
3/4
3/4
3/4
40MKCB34C----3
24AHA436
124ANS036
3/4
3/4
7/8
40MKQB34C----3
25HHA424
224ANS024
3/4
3/4
3/4
40MKQB34C----3
25HHA430
224ANS030
3/4
3/4
3/4
40MKQB34C----3
25HHA436
224ANS036
3/4
3/4
7/8
Note
:
Both lines need to be insulated using at least 1/2 inch closed
foam insulation.
Refrigerant Charge
Table 15 – Charge Requirements
System
Type
Nominal
Capacity
kBTU/Hr
Outdoor Unit
Indoor Unit
Charge to
Sub--cooling
Delta from
Rating Plate
Value
Cooling
Only
018
24AHA418A003
124ANS018000
40MKCB18C----3
12
024
24AHA424A003
124ANS024000
40MKCB34C----3
12
030
24AHA430A003
124ANS030000
40MKCB34C----3
12
034
24AHA436A003/5/6
124ANS036000
40MKCB34C----3
8
Heat
Pump
024
25HHA424A003
224ANS024000
40MKCB34C----3
14
030
25HHA430A003
224ANS030000
40MKCB34C----3
11
034
25HHA436A003/5/6
224ANS036000
40MKCB34C----3
14
The above additional charge is required amount for line lengths up to
25 ft (7.6 m). For line lengths exceeding 25 ft. (7.6 m), additional
charge will be required. Refer to the
Residential Long Line Guide
.
Metering Device
The 40MKC(Q)*C unit uses a TXV while the outdoor unit uses a
type B accurator. The cooling metering device is installed with the
indoor unit. The heating metering device is installed with the
outdoor unit. One metering device is required for the cooling only
system and two are required for the heat pump systems. Refer to
Table 16 for a breakdown of each unit’s metering devices.
Table 16 – Metering Devices
System Size
kBTU/hr
Cooling Only
Heat Pumps
40MKCB**C
40MKQB**C
25HHA4/224ANS
018
TXV
-
-
024
TXV
TXV
0.049"
030
TXV
TXV
0.055"
034
TXV
TXV
0.063"
SYSTEM EVACUATION AND
CHARGING
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Never use the system compressor as a vacuum pump.
CAUTION
!
Refrigerant tubes and indoor coil should be evacuated using the
recommended deep vacuum method of 500 microns. The alternate
triple evacuation method may be used if the procedure outlined
below is followed. Always break a vacuum with dry nitrogen.
SYSTEM VACUUM AND CHARGE
Using Vacuum Pump
1 Completely tighten flare nuts A, B, C, D, connect manifold
gage charge hose to a charge port of the low side service
valve (see Fig. 17).
2 Connect charge hose to vacuum pump.
3 Fully open the low side of manifold gage (see Fig. 18).
4 Start the vacuum pump.
5 Evacuate using either deep vacuum or triple evacuation
method.
6 After evacuation is complete, fully close the low side of the
manifold gage and stop the vacuum pump operation.
7 The factory charge contained in the outdoor unit is good for up
to 25 ft. (8 m) of line length. For refrigerant lines longer than
25 ft. (8 m), add charge, up to the maximum allowable length,
as specified in the residential
Long Line Application Guide
.
8 Disconnect charge hose from charge connection of the low
side service valve.
9 Fully open service valves B and A.
10 Securely tighten caps of service valves.
Outdoor Unit
Indoor Unit
Refrigerant
Service Valve
Low Side
High Side
A
B
C
D
A07360
Fig. 17 – Service Valve