Lennox International Inc XC21 Indoor Expansion Valve Installation, Sensing Bulb Installation

STEP 3 −− INSTALLING INDOOR EXPANSION VALVE

This outdoor unit is designed for use in systems that include an expansion valve metering device. See the XC21 Product Specifications bulletin (EHB) for approved expansion valve kit match−ups and application information. The expansion valve can be installed internal or external to the indoor coil. In applications where an uncased coil is being installed in a field−pro- vided plenum, install the expansion valve in a manner that will provide access for future field service of the expansion valve. Refer to below illustration for reference during installation of expansion valve.

INDOOR EXPANSION VALVE INSTALLATION

TWO−PIECE		(Uncased Coil Shown)
PATCH PLATE
(UNCASED				STUB
COIL ONLY)	LIQUID LINE
				END
		ORIFICE
				EXPANSION
		HOUSING
DISTRIBUTOR				VALVE
TUBES					TEFLON®
					RING
				TEFLON®	SENSING
				RING
					LINE
DISTRIBUTOR			EQUALIZER
ASSEMBLY			LINE
				LIQUID LINE
				ASSEMBLY WITH

3.Install one of the provided Teflon® rings around the stubbed end of the expansion valve and use refrigerant

oil to lightly lubricate the connector threads and ex- posed surface of the Teflon® ring.

4.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.

5.Place the remaining Teflon® washer around the other

end of the expansion valve. Lightly lubricate connector threads and expose surface of the Teflon® ring with refrigerant oil.

6.Attach the liquid line assembly to the expansion valve. Finger tighten, then use an appropriately sized wrench to turn an additional 1/2 turn clockwise as illustrated in the figure above or tighten to 20 ft−lb.

1/2 Turn

11 12		1
10		2
9		43
8 7	6	5

		BRASS NUT
MALE EQUALIZER LINE	VAPOR
FITTING (SEE
	LINE
EQUALIZER LINE
INSTALLATION FOR
DETAILS)
Sensing bulb insulation is required if
expansion valve is installed external to the		LIQUID LINE
coil casing. See sensing bulb installation for
bulb positioning.

SENSING BULB INSTALLATION

1.Attach the vapor line sensing bulb in the proper orienta- tion as illustrated below using the clamp and screws provided.

2.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

and expansion bulb before insulating the sensing bulb.

3.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.

	1/8 Turn
	11 12		1
10			2
9			43
8	7	6	5

EQUALIZER LINE INSTALLATION

1.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.

2.Remove the field−provided fitting that temporarily reconnected the liquid line to the indoor unit’s distributor assembly.

VAPOR LINE	ON LINES SMALLER THAN
	7/8", MOUNT SENSING
	BULB AT EITHER THE 3 OR
	9 O’CLOCK POSITION.
	12
BULB	BULB

FLARE SEAL CAP

OR

FLARE NUT

VAPOR LINE

COPPER FLARE
SEAL BONNET
		12
MALE BRASS EQUALIZER
LINE FITTING	BULB	BULB
VAPOR LINE

ON 7/8" AND LARGER LINES, MOUNT SENSING BULB AT EITHER THE 4 OR 8 O’CLOCK POSITION. NEVER MOUNT THE SENSING BULB ON BOTTOM OF LINE.

NOTE

BULB ON BOTTOM OF LINE.

FIGURE 9

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