Carrier 38AU appendix Prepare Unit Mounting Support, Rig and Mount the Unit, Slab Mount

Step 3 — Prepare Unit Mounting Support

Slab Mount —

Provide a level concrete slab that extends a minimum of 6 in. (150 mm) beyond unit cabinet. Install a gravel apron in front of condenser coil air inlet to prevent grass and foliage from obstructing airflow.

Step 4 — Rig and Mount the Unit

!CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage.

Table 4 – Equivalent Lengths for Common Fittings (ft)

Nominal			Elbows
Tube OD	°	°	°	°	°
	90 Std	90 Lrad	90 Street	45 Std	45 Street
3/8	1.3	0.8	2.2	0.6	1
1/2	1.4	0.9	2.3	0.7	1.1
5/8	1.6	1	2.5	0.8	1.3
3/4	1.8	1.2	2.9	0.9	1.5
7/8	2	1.4	3.2	0.9	1.6
11/8	2.6	1.7	4.1	1.3	2.1
13/8	3.3	2.3	5.6	1.7	3
15/8	4	2.6	6.3	2.1	3.4
21/8	5	3.3	8.2	2.6	4.5

38AU

All panels must be in place when rigging. Unit is not designed for handling by fork truck.

Rigging: These units are designed for overhead rigging. Refer to the rigging label for preferred rigging method. Spreader bars are not required if top crating is left on the unit. All panels must be in place when rigging. As further protection for coil faces, plywood sheets may be placed against the sides of the unit, behind cables. Run cables to a central suspension point so that the angle from the horizontal is not less than 45 degrees. Raise and set the unit down carefully.

If it is necessary to roll the unit into position, mount the unit on longitudinal rails, using a minimum of 3 rollers. Apply force to the rails, not the unit. If the unit is to be

Nominal Tube OD

3/8

1/2

5/8

3/4

7/8

11/8

13/8

15/8

21/8

Branch

Flow

2.6

2.7

3

3.5

4

5

7

8

10

Tees

Straight-Thru

No Reduct	Reduce 25%	Reduce 50%
0.8	1.1	1.3
0.9	1.2	1.4
1	1.4	1.6
1.2	1.7	1.8
1.4	1.9	2
1.7	2.3	2.6
2.3	3.1	3.3
2.6	3.7	4
3.3	4.7	5

skidded into position, place it on a large pad and drag it by the pad. Do not apply any force to the unit.

Raise from above to lift the unit from the rails or pad when unit is in its final position.

After the unit is in position, remove all shipping materials and top crating.

Step 5 — Complete Refrigerant Piping Connections

IMPORTANT: Do not bury refrigerant piping underground.

IMPORTANT: A refrigerant receiver is not provided with the unit. Do not install a receiver.

Provide Safety Relief —

If local codes dictate an additional safety relief device, purchase locally and install locally. Installation will require the recovery of the factory shipping charge before the factory tubing can be cut and the supplemental relief device is installed.

Model 38AUD has two separate refrigeration systems. If required, each circuit will require a field-supplied/installed supplemental relief device.

Check 38AU Model with Evaporator Coil Connections —

Confirm before installation of unit that the evaporator coil connections are consistent with this 38AU model. See Table 3 on page 11.

Determine Refrigerant Line Sizes —

Select the recommended line sizes for 38AUZ and 38AUD unit from the appropriate tables.

Determine the linear length of interconnecting piping required between the outdoor unit and indoor unit (evaporator). Consider and identify also the arrangement of the tubing path (quantity and type of elbows in both lines), liquid line solenoid size, filter drier and any other refrigeration specialties located in the liquid line. Refer to the indoor unit installation instructions for additional details on refrigeration specialties devices.

Determine equivalent line length adjustments for path and components and add to linear line lengths. See Table 4, Equivalent Lengths for Common Fittings, for usual fitting types. Also identify adjustments for refrigeration specialties. Refer to Part 3 of the Carrier System Design Manual for additional data and information on equivalent lengths.

NOTE: Equivalent line lengths will vary based on tube diameter. Calculate equivalent line length for each pipe by adding equivalent length adjustments to linear lengths for each pipe.

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