Specifications

APPLICATION DATA (cont)
7. System operating conditions
Operating limits:
OUTDOOR HEAT PUMP UNITS
CONDITION
538D
009,
012
538B,
538D018,
024
Maximum Cooling Ambient (F) 125 125
Minimum Cooling Ambient (F)
(without accessory low-ambient kit)
55 55
Minimum Cooling Ambient (F)
(with accessory low-ambient kit)
–20 –20
Minimum Cooling Return-Air
Temperature (F)
55 55
Maximum Cooling Return-Air
Temperature (F)
95 95
Maximum Heating Return-Air
Temperature (F)
80/71* 80/71*
Minimum Heating Return-Air
Temperature (F)
55 55
Minimum Heating Ambient
Temperature (F)
0 −20
Maximum Heating Ambient
Temperature (F)
80 80
Saturated Suction
Temperature Range
Minimum (F) –15 –15
Maximum (F) 55 55
Saturated Condensing
Temperature Range
Minimum (F) 85 80
Maximum (F) 150 150
Maximum Compressor Discharge
Temperature (F)
275 275
Minimum Discharge Superheat (F) 60 60
*Dry bulb/wet bulb.
FAN COIL UNITS
CONDITION 619E 619C 619F
Maximum Room
Temperature (F)
84 84 95
Minimum Room
Temperature (F)
64 64 55
Maximum Return Air (F)
Dry-Bulb 85 85 85
Wet-Bulb 72 72 72
Minimum Return Air (F) 28 28 28
Maximum Saturated
55 55 55
Suction Temperature (F)
Minimum Saturated
27 27 27
Suction Temperature (F)
8. Low-ambient operation
Units can operate in cooling down to 55 F under all condi-
tions without a low-ambient kit.
Units equipped with accessory low-ambient kits should also
be equipped with accessory wind baffle, isolation relay, and
crankcase heater (scroll units). Wind baffle must be field-
fabricated.
a. Freezestat — Freeze-up protection is provided on all
duct-free fan coil units.
b. Crankcase heater — Scroll compressor units with low-
ambient control or scroll compressor units in long-line
applications should be equipped with crankcase heaters
to prevent refrigerant migration during compressor off
cycle.
9. Metering devices
The 538D and 538B units use a piston-type metering
device located in the indoor unit (for cooling) and in the out-
door liquid service valve (for heating). Pistons function as
check valves in addition to being metering devices.
NOTE: All duct-free split systems (except high-wall sys-
tems using 619E009,012) use Type ‘‘B’’ Chatleff style
AccuRaterT pistons. DO NOT mix Type ‘‘A’’ and Type ‘‘B’’
pistons. See Long-Lines Applications section on page 66
for changes in piston sizes due to long lines.
10. Drain connections
Install drains to meet local sanitation codes. If adequate
gravity drainage cannot be provided, unit should be
equipped with accessory condensate pump.
NOTE: The 619F units have a condensate pump installed
as standard from the factory.
High wall fan coil units with accessory condensate pumps
havea1to10ftlift (009 size) or 3 to 25 ft lift (012-
024 sizes). All other fan coil units have a lift capability of
20 in. above the condensate pan level.
See base unit dimensional drawings on pages 18-24 for
drain locations and sizes.
NOTE: High wall fan coil units have internal condensate
traps. All other fan coil units require a field-supplied external
condensate trap.
Drain connections may be routed through alternate loca-
tions on most fan coils. See base unit dimensional drawings
on pages 18-24 for possible alternate locations.
11. Refrigerant lines
a. General refrigerant line sizing:
• All charges, line sizing, and capacities are based on
runs of 25 ft. For runs over 25 ft, consult long-lines
section on page 66 for proper line sizing, charge, and
AccuRater refrigerant metering device sizing.
NOTE: For runs less than 25 ft, some of the charge
may need to be removed to obtain the correct system
superheat. The minimum line length should be 8 ft.
MAXIMUM LINE LENGTHS
UNIT
MAXIMUM
EQUIVALENT
(ft)
MAXIMUM
LIFT —
FAN COIL
BELOW
OUTDOOR
UNIT
MAXIMUM
LIFT —
FAN COIL
ABOVE
OUTDOOR
UNIT
538D009,
012
35 30 16
538B,
538D018,
024
200 150 65
• Refrigerant lines should not be buried in the ground. If
it is necessary to bury the lines, not more than
36 in. should be buried. Provide a minimum 6-in. ver-
tical rise to the service valves to prevent refrigerant
migration.
• The vapor line must be insulated. Use a minimum of
1
⁄ 2 -in. thick insulation. Closed-cell insulation is recom-
mended in all long-line applications.
• Special consideration should be given to isolating
interconnecting tubing from the building structure.
Isolate the tubing so that vibration or noise is not
transmitted into the structure.
65