Lennox Merit 13ACX-018-230 Installation Instructions Manual page 8

STEP 2 -- REFRIGERANT PIPING -- Installing Indoor Expansion Valve
This outdoor unit is designed for use in systems that use either an fixed orifice (RFC) (included with outdoor unit), or
expansion valve metering device (purchased separately) at the indoor coil. See the 13ACX Product Specifications bulletin
(EHB) for approved expansion valve kit match ups. The expansion valve unit 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 expansion valve in a
manner that will provide access for field servicing of the expansion valve. Refer to below illustration for reference during
installation of expansion valve unit. After installation of the indoor coil metering device, proceed to Step 5.
INDOOR EXPANSION VALVE INSTALLATION
TWO-PIECE
(Uncased Coil Shown)
PATCH PLATE
(UNCASED
LIQUID LINE
COIL ONLY)
ORIFICE
HOUSING
DISTRIBUTOR
TUBES
DISTRIBUTOR
ASSEMBLY
MALE EQUALIZER LINE
FITTING (SEE
EQUALIZER LINE
INSTALLATION FOR
DETAILS)
Sensing bulb insulation is required if
expansion valve is installed external to the
coil casing. See sensing bulb installation for
bulb positioning.
EQUALIZER LINE INSTALLATION
A Remove and discard either the flare seal cap or flare nut with
copper flare seal bonnet from the equalizer line port on the vapor
line as illustrated in the figure below.
B Remove the field-provided fitting that temporarily reconnected
the liquid line to the indoor unit's distributor assembly.
FLARE SEAL CAP
STUB
END
EXPANSION
VALVE
TEFLON
RING
®
TEFLON
SENSING
RING
EQUALIZER
LINE
LIQUID LINE
ASSEMBLY WITH
BRASS NUT
VAPOR
LINE
LIQUID LINE
FLARE NUT
COPPER FLARE
OR
SEAL BONNET
MALE BRASS EQUALIZER
LINE FITTING
VAPOR LINE
C Install one of the provided Teflon
stubbed end of the expansion valve and use refrigerant
oil to lightly lubricate the connector threads and ex­
posed surface of the Teflon
D Attach the stubbed end of the expansion valve to the
liquid line orifice housing. Finger tighten, then use an
appropriately sized wrench to turn an additional 1/2
turn clockwise as illustrated in the figure to the right, or
tighten to 20 ft-lb.
® E Place the remaining Teflon
end of the expansion valve. Lightly lubricate connector
threads and expose surface of the Teflon
refrigerant oil.
F Attach the liquid line assembly to the expansion valve.
Finger tighten, then use an appropriately sized wrench
LINE
to turn an additional 1/2 turn clockwise as illustrated in
the figure above or tighten to 20 ft-lb.
SENSING BULB INSTALLATION
A Attach the vapor line sensing bulb in the proper orienta­
tion as illustrated below using the clamp and screws
provided.
B NOTE - Though it is preferred to have the sensing bulb
installed on a horizontal run of the vapor line, installation
on a vertical run of piping is acceptable if necessary.
NOTE — Confirm proper thermal contact between vapor line
and expansion bulb before insulating the sensing bulb.
C Connect the equalizer line from the expansion valve to
the equalizer vapor port on the vapor line. Finger tighten
the flare nut, then tighten an additional 1/8 turn (7 ft-lbs)
as illustrated to the right.
VAPOR LINE
BULB
VAPOR LINE
BULB
NOTE — NEVER MOUNT THE SENSING
BULB ON BOTTOM OF LINE.
FIGURE 10
Page 8
®
rings around the
®
ring.
®
washer around the other
®
ring with
ON LINES SMALLER THAN
7/8", MOUNT
BULB AT EITHER THE 3 OR
9 O'CLOCK POSITION.
12
BULB
ON 7/8" AND LARGER LINES,
MOUNT SENSING BULB AT
EITHER THE 4 OR 8 O'CLOCK
POSITION. NEVER
THE SENSING
12
BOTTOM OF LINE.
BULB
1/2 Turn
11 12
1
2
10
9 3
4
8
5
7
6
1/8 Turn
11 12
1
2
10
9 3
4
8
7 5
6
SENSING
MOUNT
BULB ON