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505361M 09/07
Replacing Refrigerant Metering Device
13HPD units are used in check thermal expansion valve
(CTXV) and fixed orifice systems. See the indoor unit
installation instruction and the Lennox Engineering
Handbook for approved metering device and application
information. Table 2 lists liquid and vapor connection
sizes, line sizes and corresponding line set.
Remove the existing HCFC−22 fixed orifice device or
CTXV from the indoor coil if required. See figure 14 for
disassembly and typical removal instructions.
The CTXV can be installed internal or external to the indoor
coil. In applications where an uncased coil is being
installed in a field provided plenum, install the CTXV in a
location that will provide easy access for field servicing.
Refer to Figure 15 for reference during installation of
CTXV.
REMOVE AND DISCARD
SEAL ASSEMBLY (IF
APPLICABLE)
TWO PIECE PATCH
PLATE(UNCASED
COIL ONLY)
VAPOR
LINE
ORIFICE
HOUSING
DISTRIBUTOR
TUBES
LIQUID
LINE
Sensing bulb (insulation
required, if mounted
external to the coil casing.
ACCESS FITTING
(NO VALVE CORE)
SENSING
LINE
EQUALIZER
LINE
ORIFICE
OR
EXPANSION VALVE
(SEE NOTE)
O−RING
STRAINER
(Uncased Coil Shown)
O−RING
Figure 14. Typical Metering Device Installation
FIXED ORIFICE SYSTEMS
Replace the existing indoor unit fixed orifice with the orifice
supplied with the outdoor unit. Place the supplied fixed
orifice sticker on the indoor cabinet after installation.
Table 3. Fixed Orifice Part Numbers
Model
HCFC−22
13HPD
018
100484−08 (0.057)
024
100484−11 (0.061)
030
100484−21 (0.072)
036
100484−23 (0.074)
042
100484−30 (0.082)
037 and 048
Not Supported
060
100484−44 (0.098)
See table 3 for the fixed orifice size for each unit. In
non−standard applications, the provided fixed orifice may
not be appropriate.
CTXV SYSTEMS
1. On fully cased coils, remove the coil access and
plumbing panels.
2. Remove any shipping clamps holding the liquid line
and distributor assembly.
3. Using two wrenches, disconnect liquid line from
distributor. Take care not to twist or damage distributor
tubes during this process.
NOTE − If necessary, remove existing flow control device
(fixed orifice or expansion valve) from existing line set
before installing approved metering device.
4. Remove and discard RFC orifice and Teflon washer.
5. Remove and discard cap from the equalizer line port
on the vapor line. Check for valve core in port fitting
and if installed, remove from port.
6. Install one of the provided Teflon washers around the
stubbed end of the CTXV.
7. Attach the stubbed end of the kit valve to the distributor
assembly.
8. Place the remaining Teflon washer around the other
end of the CTXV.
9. Attach the liquid line to the CTXV.
10. Attach the sensing bulb of the CTXV in the proper
orientation as illustrated in figure 15 to the vapor line
using the clamp an screws provided with the CTXV.
On 7/8" and larger lines,
mount sensing bulb at
either the 4 or 8 o’clock
position. Never mount
on bottom of line.
12
On lines smaller than
7/8", mount sensing bulb
at either the 3 or 9 o’clock
position.
Bulb
12
Bulb
Bulb
Bulb
Vapor Line
Vapor Line
NOTE − Never mount on bottom of line.
Figure 15. CTXV Sensing Bulb Installation
NOTE − Insulating the sensing bulb once installed may be
required when the bulb location is external to the coil
casing.
11. Connect the equalizer line port from the CTXV to the
equalizer port on the vapor line.
12. To prevent any possibility of water damage, properly
insulate all parts of the CTXV assembly that may
sweat due to its surrounding ambient
