Application Data; Metering Devices; Refrigerant Lines - Carrier 40MBD Product Data

APPLICATION DATA

UNIT SELECTION
Select equipment to either match or be slightly less than anticipated
peak load. This provides better humidity control, fewer unit cycles,
and less part- load operation.
For units used in spaces with high sensible loads, base equipment
selection on unit sensible load, not on total anticipated load. Adjust
for anticipated room wet bulb temperature to avoid undersizing
equipment.
UNIT MOUNTING (INDOOR)
Refer to unit Installation Instructions for further details.
Unit leveling - For reliable operation, units should be level in all
planes.
Clearance - Provide adequate clearance for airflow as shown in
Fig. 3.
Unit location - Select a location which will provide the best air
circulation for the room.
These units should be positioned as accessible as possible above
the ceiling. The unit return and discharge should not be obstructed
by furniture, curtains, or anything which may cause unit short
cycling or air recirculation. Duct the unit in the middle of the
selected wall (if possible). Duct towards an outside wall, if
available, to make piping easier, and place the unit so it faces the
normal location of room occupants.
UNIT MOUNTING (OUTDOOR)
Refer to unit Installation Instructions for further details.
Unit leveling - For reliable operation, units should be level in all
planes.
Clearance - Minimum clearance, as shown in Fig. 5, 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.
A location which can bear the weight of outdoor unit and where
the outdoor unit can be mounted in a level position.
Do not install the indoor or outdoor units in a location with special
environmental conditions. For those applications, contact your
Carrier representative.
MOUNTING
Refer to unit Installation Instructions for further details.
SUPPORT
Adequate support must be provided to support the weight of all fan
coils. Refer to the Physical Data section for fan coil weights, and
the base unit dimensional drawings for the location of mounting
brackets.
SYSTEM OPERATING CONDITIONS
Operating Range
Min / Max °F (°C)
Cooling
Outdoor DB 4 / 122 (-20 / 50)
Indoor DB 63 / 90 (17 / 32)
Indoor WB 59 / 84 (15 / 29)
Non-Operating Temperature Range
Min / Max °F (°C)
Indoor/Outdoor DB
NOTE: Reference the Product Installation Instructions for more
information.

METERING DEVICES

The outdoor unit (Sizes 09, 12, 18, 36 & 48) has an electronic
expansion valve to manage the refrigerant flow of the fan coil
connected. Size 24 has capillary tube metering devices in the
outdoor unit.
DRAIN CONNECTIONS
Install drains to meet local sanitation codes. Standard ducted fan
coil unit condensate pumps have a maximum lift of 29.5in
(750mm).

REFRIGERANT LINES

General refrigerant line sizing:
1. The 38MAQ & 38MBQ units are shipped with a full
charge of R410A refrigerant. All charges, line sizing, and
capacities are based on runs of 25 ft (7.6 m). For runs over
25 ft (7.6 m), consult long- line section on this page for
proper charge adjustments.
2. 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.
3. 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.
4. 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.
Long Line Applications, 38MAQ & 38MBQ Units:
1. No change in line sizing is required.
2. Add refrigerant per table below.
ADDITIONAL CHARGE TABLE
Total Line
Additional Charge, oz/ft. Ft (m)
Length ft
Unit
Size 10-25
Min Max
(3-8)
9
82
12
18
10 98 None
24
36
213
48
12
Heating
4 / 86 (-20 / 30)
32 / 86 (0 / 30)
32 / 86 (0 / 30)
>25-82 >82-98
>98-213
(30-65)
(8-25) (25-30)
0.27
0.43 0.43
0.43