Page 15
XC21 SERIES
A
Attach the vapor line sensing bulb in the proper orientation
as illustrated to the right using the clamp and screws pro-
vided.
NOTE Confirm proper thermal contact between vapor line
and check expansion bulb before insulating the sensing bulb
once installed.
B
Connect the equalizer line from the
check expansion valve to the
equalizer vapor port on the vapor
line. Finger tighten the flare nut
plus 1/8 turn (7 ft−lbs) as illus-
trated below.
The check 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 check
expansion valve in a manner that will provide access for field
servicing of the check expansion valve. Refer to below
illustration for reference during installation of check expansion
valve unit.
TYPICAL CHECK EXPANSION VALVE INSTALLATION PROCEDURE
TWO PIECE
PATCH PLATE
(UNCASED
COIL ONLY)
VAPOR
LINE
LIQUID LINE
ORIFICE
HOUSING
DISTRIBUTOR
TUBES
LIQUID LINE
MALE EQUALIZER LINE
FITTING (SEE
EQUALIZER LINE
INSTALLATION FOR
FURTHER DETAILS)
SENSING
LINE
EQUALIZER
LINE
CHECK
EXPANSION
VALVE
TEFLON
RING
(Uncased Coil Shown)
SENSING BULB INSULATION IS REQUIRED
IF MOUNTED EXTERNAL TO THE COIL
CASING. SENSING BULB INSTALLATION
FOR BULB POSITIONING.
STUB
END
TEFLON
RING
LIQUID LINE
ASSEMBLY WITH
BRASS NUT
DISTRIBUTOR
ASSEMBLY
This outdoor unit is designed for use in systems that use check expansion valve metering device. See the
Lennox XC21
Engineering Handbook
for approved check expansion valve kit match−ups and application information.
A
Remove the field−provided fitting that temporary reconnected the liquid
line to the indoor unit’s distributor assembly.
B
Install one of the provided Teflon rings around the stubbed end of the
check expansion valve and lightly lubricate the connector threads and
expose surface of the Teflon ring with refrigerant oil.
C
Attach the stubbed end of the check expansion valve to the liquid line
orifice housing. Finger tighten and use an appropriately sized wrench to
turn an additional 1/2 turn clockwise as illustrated in the figure above, or
20 ft−lb.
D
Place the remaining Teflon washer around the other end of the check
expansion valve. Lightly lubricate connector threads and expose sur-
face of the Teflon ring with refrigerant oil.
E
Attach the liquid line assembly to the check expansion valve. Finger
tighten and use an appropriately sized wrench to turn an additional 1/2
turn clockwise as illustrated in the figure above or 20 ft−lb.
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.
12
BULB
VAPOR LINE
VAPOR LINE
NOTE NEVER MOUNT ON BOTTOM OF LINE.
BULB
BULB
BULB
VAPOR LINE
FLARE NUT
COPPER FLARE
SEAL BONNET
MALE BRASS EQUALIZER
LINE FITTING
FLARE SEAL CAP
OR
1
2
3
4
5
6
7
8
9
10
11 12
1/2 TURN
SENSING BULB INSTALLATION
EQUALIZER LINE INSTALLATION
1
2
3
4
5
6
7
8
9
10
11 12
1/8 TURN
FLUSHING LINE SET AND INDOOR COIL (2 OF 2)
4
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 to the right.
B
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 to the right.
Summary of Contents for XC21
Page 21: ...Page 21 XC21 SERIES Figure 8 Typical XC21 Wiring ...
Page 39: ...Page 39 XC21 SERIES Figure 19 High Pressure Switch Operation ...
Page 40: ...Page 40 506518 01 Figure 20 Low Pressure Switch Operation ...
Page 41: ...Page 41 XC21 SERIES Figure 21 High Discharge Temperature Sensor Operation ...
