Bryant 541A Refrigerant Specialties Part Numbers, F. Provide Safety Relief, Minimum Outdoor Air

Table 4 — Refrigerant Specialties Part Numbers

UNIT	LIQUID LINE	LIQUID LINE	LLSV COIL	SIGHT GLASS	FILTER DRIER
	SIZE	SOLENOID VALVE (LLSV)
575B072	1/2″	200RB GS-1928 5T4	AMG-24/50-60	AMI1TT4	*
	5/8″	200RB GS-1929 5T5	AMG-24/50-60	AMI1TT5	*
575C090	3/8″	200RB GS-1928 5T4†	AMG-24/50-60	AMI1TT3	P504-8083S
	1/2″	200RB GS-1928 5T4	AMG-24/50-60	AMI1TT4	P504-8084S
575C120	1/2″	200RB GS-1928 5T4	AMG-24/50-60	AMI1TT4	P504-8164S
541A180	5/8″	**	**	AMI1TT5	P504-8085S Qty 2
	3/4″	**	**	AMI1TT5	P504-8085S Qty 2

*A filter drier is shipped loose with the 575B072 units. †Bushings required.

**Factory Installed.

F. Provide Safety Relief

A fusible plug is located on the compressor crankcase or in the liquid line. See Fig. 6. Do not cap this plug. If local code requires additional safety devices, install them as directed.

Head Pressure Control (541A180 only)

Fan cycling for head pressure control is a standard offering but is functional on the cooling cycle only. Number 2 fan cycles as a function of liquid pressure. Fan cycling pressure switch cycles the fan off at 160 ± 10 psig as pressure decreases and cycles back on at 255 ± 10 psig. Switch is auto- matically bypassed in heating cycle. Table 5 shows minimum outdoor air temperature for full cooling capacity.

G. Vapor Line Piping Procedure

Connect system vapor line to the vapor line stub on the out- door unit and the vapor stubs on the indoor unit. At the indoor unit, construct vapor piping branches as shown in Fig. 7 for good mixing of the refrigerant leaving the indoor coil during cooling. This will ensure proper TXV (thermo- static expansion valve) bulb sensing.

Where vapor line is exposed to outdoor air, line must be insu- lated. See Table 6 for insulation requirements.

Table 5 — Minimum Outdoor Air

Operating Temperature

		%	MINIMUM OUTDOOR TEMP — F*
UNIT		COMPRESSOR	Standard	Head Pressure
		CAPACITY	Unit	Control†
575B	072		0	0
575C	090	100	35	–20
	120		35	–20
541A	180	100	23	–20
		67	36	–20

*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 6 — Insulation for Vapor Line Exposed

to Outdoor Conditions

LENGTH OF EXPOSED	INSULATION THICKNESS†
VAPOR LINE*
ft	in.
10	3/8
25	1/2
35	3/4
50	3/4

Fig. 6 — Location of Fusible Plug —

541A180 Unit

LEGEND

TXV — Thermostatic Expansion Valve

Fig. 7 — Vapor Line Branch Piping Details

*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 pre- vent condensation on cooling cycle. Heating capacity should be reduced 1000 Btuh if over 35 ft of vapor line with 3/4 in. insulation is exposed to outdoor conditions.

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

• in./ft2 • h • °F.

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