Carrier 38AUQ appendix Install Liquid Line Solenoid Valve, Unit Damage Hazard

Table 5 — Refrigerant Specialties Part Numbers.

LIQUID LINE		LIQUID LINE	LLSV	SIGHT	FILTER
SIZE (in.)		SOLENOID VALVE (LLSV)	COIL	GLASS	DRIER
3/8		ALC-066208	AMG-24/50-60	HMI-1TT3	Provided with unit
1/	2	ALC-066209†	AMG-24/50-60	HMI-1TT4
					See Table 4
5/8		ALC-066212	AMG-24/50-60	HMI-1TT5

†38AUD units require TWO sets of parts.

INSTALL LIQUID LINE SOLENOID VALVE —

It is recommended that a bi-directional solenoid valve be placed in the main liquid line (see Figs. 5 & 6) between the outdoor unit and the indoor coil. Locate the solenoid valve at the end of the liquid line, near the outdoor unit connections, with flow direction arrow pointed at the outdoor unit. Refer to Table 5. (A liquid line solenoid valve is required when the liquid line length exceeds 75 ft [23 m].) This valve prevents refrigerant migration (which causes oil dilution) to the compressor during the off cycle, at low outdoor ambient temperatures. Wire the solenoid according to the unit label diagram.

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage.

Failure to use a solenoid valve relay (SUR) accessory may cause overload of Comfort Alert Diagnostic Module (CADM) and compressor alarm lock out.

CAPACITY CONTROL LIQUID LINE SOLENOID VALVE Evaporator capacity control via liquid solenoid valve is not rec- ommended for use with 38AUQ models.

	TXV		EQUALIZER LINE
INDOOR
	SENSING		SIGHT GLASS
COIL CKT	BULB
			A LOCATION
			FILTER DRIER
			A LOCATION
AIRFLOW	15 DIAMS		TXV
		10
	MIN
		DIAMS
		8 DIAMS	FLOW
		MIN
			LIQUID
			LINE
			SOLENOID
			VALVE

LEGEND

TXV — Thermostatic Expansion Valve

Fig.5 — Location of Sight Glass(es) and Filter Driers

(typical 38AUQ/40RUQ size 07 & 08 systems)

	TXV		EQUALIZER LINE
INDOOR
	SENSING
COIL CKT 2	BULB
				SIGHT GLASS
			TXV	LOCATION
AIRFLOW	15 DIAMS			FILTER DRIER
		10	CKT 2	LOCATION
	MIN
		DIAMS	8 DIAMS
			MIN
	TXV			FLOW
INDOOR	SENSING			LIQUID
COIL CKT 1	BULB			LINE
				SOLENOID
				VALVE
AIRFLOW	15 DIAMS		TXV
		10	CKT 1
	MIN
		DIAMS

8DIAMS

MIN

LEGEND

TXV — Thermostatic Expansion Valve

Fig.6 — Location of Sight Glass(es) and Filter Driers

(typical 38AUQ/40RUQ size 12 system)

Table 6 — Minimum Outdoor Air Operating Temperature

	%	MINIMUM OUTDOOR
		TEMP — F (C)*
UNIT	COMPRESSOR
	CAPACITY	Standard Unit	Head Pressure
			Control†
38AUQ07		35 (1.7)	–20 (–28.9)
38AUQ08	100	35 (1.7)	–20 (–28.9)
38AUQ12		35 (1.7)	–20 (–28.9)

*Applies to Cooling mode of operation only.

†Wind baffles (field-supplied and field-installed) are recommended for all units with low ambient head pressure control. Refer to Low Ambient Control Installation Instructions (shipped with accessory) for details.

Table 7 — Insulation for Vapor Line Exposed

to Outdoor Conditions

LENGTH OF EXPOSED		INSULATION THICKNESS†
VAPOR LINE*
ft	m	in.	mm
10	3	3/8	10
25	8	1/2	13
35	11	3/4	19
50	15	3/4	19

*Recommended vapor line insulation for piping exposed to outdoor conditions to prevent loss of heating during heating cycle. When vapor line goes through interior spaces, insulation should be selected to prevent condensation on cooling cycle. Heating capac- ity should be reduced 1000 Btuh (295 W) if over 35 ft (11 m) of vapor line with 3/4 in. (19 mm) insulation is exposed to outdoor con- ditions.

†Closed cell foam insulation with a thermal conductivity of: 0.28 Btu

• in./ft2 • h • °F (0.04 W/m • °C).

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