Application Data; Refrigerant Lines - Carrier 40KMC Product Data

APPLICATION DATA

UNIT SELECTION
The in- -ceiling cassette units are available as cooling only, cooling
only with electric heat, or heat pumps with electric heat. For most
applications, the cooling load dictates the size selection. Select
equipment to either match or be slightly less than anticipated peak
load. This provides better humidity control, fewer unit cycles, and
better low load performance.
For units used in spaces with high sensible loads, base equipment
selection on unit sensible load, not on total anticipated load to
avoid oversizing the equipment.
UNIT MOUNTING (INDOOR)
Unit leveling - - For reliable operation, units should be level in all
planes. Align and level the unit by adjusting the nuts and
lock- -nuts on the threaded hangers.
Clearance - - A minimum of 12 inches (304.8 mm) of clearance is
required in the false ceiling.
Unit location - - Placing the unit in the center of the room will
provide the best air circulation and comfort.
The unit return and discharge should not be obstructed by anything
which may cause unit short cycling or air recirculation.
Support - - Threaded hangers should be used to install the unit and
the structure should provide adequate support for the weight of the
unit.
Installation Template - - Fan coil units are supplied with a
cardboard template to help match the position of the hangers,
refrigerant lines, condensate drain pipe and power supply cable.
UNIT MOUNTING (OUTDOOR)
Unit leveling - - For reliable operation, units should be level in all
planes.
Clearance - - Minimum clearance, as shown in Fig. 7, must be
provided for airflow. The condensing units are designed for
free- -blow application. Air inlets and outlets should not be
restricted.
Unit location - - A location which is convenient to installation and
not exposed to strong wind. If unit is exposed to strong winds it is
recommended that a wind baffle accessory be used.
A location which can bear the weight of outdoor unit and where
the outdoor unit can be mounted in a level position.
Mounting Pad - - The minimum mounting pad dimensions are
listed in the following table:
MAXIMUM MOUNTING PAD DIMENSIONS
UNIT MODEL
38HDF018, 024, 030
38QRF018, 024
38HDF036
38QRF030, 036
SYSTEMS OPERATING CONDITIONS
Cooling Operating Range
Maximum
DB ° F (° C) WB ° F (° C)
Outdoor
125 (51.7) --- ---
Unit
Indoor
90 (32.2) 74 (23.3)
Unit
ft--- in. (mm)
1'---11" X 3'---6"
(584.2 X 1066.8)
2'---0" X 4'---2"
(609.6 X 1270)
Minimum
DB ° F (° C) WB ° F (° C)
55 (12.8) --- ---
62 (17.0) 56 (13)
Heating Operating Range
Maximum
DB ° F (° C) WB ° F (° C)
Outdoor
75 (23.9) 67 (19.4)
Unit
Indoor
81 (27.2)
Unit
Low Ambient Operation
Both cooling only and heat pumps will operate in cooling down to
55_F (12.8_C).
When equipped with a Low Ambient Controller, the unit will
operate down to - -20_F (- -28.9_C).
For proper operation of cooling only units, a Winter Start Kit
(bypasses the Low Pressure Switch), a Crankcase Heater (prevents
refrigerant migration during compressor- -off cycle), and a Wind
Baffle should also be installed.
On heat pumps, a Winter Start Kit will not be required. An
Isolation Relay to bypass the Low Ambient Controller when unit is
in heating mode will be required.
Metering Devices
An Accurator installed at the outdoor unit is used as a metering
device. This requires that both refrigerant lines be insulated. (A
heat pump unit has 2 AccuRater.)
Drain Connections
The in- -ceiling cassette is supplied with a pump that is capable of
lifting the water 7.8" (200 mm) above the top of the unit. A
downward sloped condensate drain pipe can be used to dispose of
water.

REFRIGERANT LINES

General refrigerant line sizing:
1. Refrigerant lines should not be buried in the ground. If it is
necessary to bury the lines, not more than 36- -in (914 mm)
should be buried. Provide a minimum 6- -in (152 mm)
vertical rise to the service valves to prevent refrigerant
migration.
2. Both lines must be insulated. Use a minimum of 1/2- -in.
(12.7 mm) thick insulation. Closed- -cell insulation is
recommended in all long- -line applications.
3. 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.
NOTE: Since the same outdoor unit can be matched with
different types of indoor units, it may not have enough
refrigerant charge. Refer to the Physical Data tables to
determine if additional charge is required.
Long Line Applications
The following table indicates the maximum line lengths that can be
used with the high wall systems.
ITEM
Total Piping
Max Lift (Fan Coil above)
Max Drop (Fan Coil below)
For line lengths over 25 ft (7.6 m), .3 oz (.009 kg) of charge should
be added for each additional foot up to the maximum allowed.
For line lengths over 80 ft (24.4 m), certain accessories and
adjustments to the piston sizes are also required.
Refer to the Duct- -Free Split Systems Long Line Guide for
additional information.
28
Minimum
DB ° F (° C) WB ° F (° C)
17 ( ---8.3) --- ---
--- --- 62 (17.0) --- ---
MAX LENGTH ALLOWED
ft (m)
200 (61)
65 (20)
200 (61)