Lennox International Inc 06/11 50672801 Installing New Indoor Metering Device, Uncased Coil Shown

Installing New Indoor Metering Device

This outdoor unit is designed for use in HFC−410A systems that use a check / expansion valve metering device (purchased separately) at the indoor coil.

See the Lennox XP13 Engineering Handbook for approved check / expansion valve kit match−ups. The check / expansion valve device can be installed either 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 (see figure 11).

INDOOR EXPANSION VALVE INSTALLATION

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

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

BInstall 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.

CAttach the stubbed end of the 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.

DPlace the remaining Teflon® washer around the other end of the check / expansion valve. Lightly lubricate connector threads and expose surface of the Teflon® ring with refrigerant oil.

EAttach 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.

1/2 Turn

11 12		1
10		2
9		43
8 7	6	5

ASSEMBLY WITH

BRASS NUT

SENSING BULB INSTALLATION

MALE EQUALIZER LINE	VAPOR
FITTING (SEE
	LINE
EQUALIZER LINE
INSTALLATION FOR	LIQUID LINE
FURTHER DETAILS)

Sensing bulb insulation is required if mounted external to the coil casing.

AAttach the vapor line sensing bulb in the proper orientation as illustrated to the right using the clamp and screws provided.

NOTE

and expansion bulb before insulating the sensing bulb once installed.

BConnect 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 illustrated below.

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

EQUALIZER LINE INSTALLATION

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.

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
		ON 7/8" AND LARGER LINES,
		MOUNT SENSING BULB AT
COPPER FLARE		EITHER THE 4 OR 8 O’CLOCK
SEAL BONNET	12	POSITION. NEVER MOUNT ON
		BOTTOM OF LINE.
MALE BRASS EQUALIZER	BULB	BULB
LINE FITTING

VAPOR LINE NOTE OM OF LINE.

	Figure 11. Installing Indoor Check / Expansion Valve
506728−01	Page 16