Carrier R-410A manual Refrigerant and Chilled Water Piping Access Holes

Unit Isolation — Where extremely quiet operation is essential, install isolators between floor and base of unit, or between ceiling and top section of unit.

Be sure that unit is level and adequately supported. Use channels at front and sides of unit for reference points when leveling.

Refrigerant and Chilled Water Piping Access — The 40RU Series units come with standard knockouts for refrigerant and chilled water piping. These knockouts are located on both sides of the unit for installation flexibility. The standard knockouts provide sufficient access to the unit’s coils for all 40RUA*25, 28, and 30 units. RUS*25, 28, and 30 units require additional holes which must be field- fabracated to accomodiate the piping. See Fig. 7 for the positions and dimensions of the additional access holes required for the RUS units. Recommended access hole use is also listed for all units. Note that Fig. 7 shows the access holes on the control-box side of the unit; this is the side of the unit with the coil headers, so it is used most often for piping access.

IMPORTANT: Do not bury refrigerant piping underground.

Refrigerant Piping — See Tables 1A–1D for refrigerant pipe connection sizes. For ease in brazing, it is recommended that all internal solder joints be made before unit is placed in final position.

The 40RU direct-expansion units have internal factory-installed thermostatic expansion valves (TXVs), distributors, and nozzles for use with R-410A. See Table 2 for part numbers. Knockouts are provided in the unit corner posts for 40RU refrigerant piping. See Fig. 7, which also lists recommended knockouts and access holes to use for each 40RU unit size. Recommended fittings are listed in Table 3.

The sensor bulb capillary tubes must be routed from the TXVs inside the unit through one of the piping access holes. Clamp the TXV sensor bulb on a vertical portion of the suction line, outside the unit. See Fig. 8.

NOTE: Be sure to remove the styrofoam shipping pad from the TXV. Verify that it has been removed. See Fig. 1.

IMPORTANT: Never attach the sensor to the suction manifold. Do NOT mount the sensor on a trapped portion of the suction line.

The 40RU Series evaporator coils have a face-split design. Ensure that lower circuit of coil is first on/last off when connected to the condensing unit and/or system controls. See Fig. 9.

External TXV equalizer connections are provided and factory-brazed into the coil suction manifolds.

If suction line must be horizontal, clamp bulb to suction line at least 45 degrees above bottom, at approximately the 4 o’clock or 8 o’clock position. See Fig.10.

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7

6

5

4

3

2

1

A

B

C

D

	USE HOLE	FIELD-FABRICATED HOLE DIAMETERS					FIELD-FABRICATED HOLE POSITION
UNIT			in. (mm)					DIMENSIONS, in. (mm)
	NUMBERS
		No. 5	No. 6	No. 7	No.8		A	B		C		D
40RUA*25, 28, 30	1, 2, 3, 4	—	—	—	—		—	—		—		—
40RUS*25	4, 5, 6, 7	13/4 (44.5)	13/4 (44.5)	13/4 (44.5)	—	3.0	(76.2)	6.0 (152.5)	10.5	(266.7)
40RUS*28, 30	5, 6, 7, 8	21/2 (63.5)	21/2 (63.5)	21/2 (63.5)	21/2 (63.5)	6.0	(152.5)	9.625 244.5)	13.38	(339.9)	17.0	(431.8)

Fig. 7 — Refrigerant and Chilled Water Piping Access Holes

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