Toshiba HFC R-410A manual System restrictions, Allowable value, Piping section

3. Allowable length/height difference of refrigerant piping

Height difference between outdoor units H3 ≤ 5 m

Height difference betweeen outdoor units H1 ≤ 50 m

D slave

Example 1

Example 2

unit 3

Master

Slave

Slave

Master

Slave

Slave

A master

B slave

C slave

unit

unit 1

unit 2

unit

unit 1

unit 2

unit

unit 1

unit 2

Connecting

Outdoor unit

piping of

outdoor unit

T-shape branching

La

LA

Lb

LB

Lc

Ld

joint

Main connecting piping between outdoor units

Note: In case of connecting method in Example 2, a large amount of

Length corresponding to farthest piping

Main

between outdoor units LO ≤ 25 m

refrigerant and refrigerant oil may return to the master unit. Therefore,

set the T-shape joint so that oil does not enter directly.

piping

			Branching
L1	Branching piping	L2	header
	Connecting piping of indoor unit
	1st branching
	section
	L3		Indoor unit
	Equivalent length corresponding to farthest piping L ≤ 175 m

	Equivalent length corresponding to farthest piping after 1st branching Li ≤ 65 m				Height difference
					between indoor
			L5	L6
		L4			units H2 ≤ 30 m
Y-joint

							Indoor unit
System restrictions					Note 1:
						Combination of outdoor units: Master unit (1 unit) + slave units (0 to 3 units).
						Master unit is the outdoor unit nearest to the connected indoor units.
					Note 2:	Install the outdoor units in order of capacity.
Max. No. of combined outdoor units				4 units	Note 3:	(Master unit ≥ slave unit 1 ≥ slave unit 2 ≥ slave unit 3)
Max. capacity of combined outdoor units				48 hp		Refer to outdoor unit combination table on page 7.
Max. No. of connected indoor units				48 units	Note 4:	Piping to indoor units shall be perpendicular to piping to the master outdoor unit as in
Max. capacity of combined		H2	≤ 15	135%		Example 1. Do not connect piping to indoor uints in the same direction as the master
indoor units		H2	> 15	105%		outdoor unit in Example 2.
Allowable length and height difference of refrigerant piping
							Allowable value	Piping section
Piping length	Total extension of pipe (liquid pipe, actual length)						300 m	LA + LB + La + Lb + Lc + Ld + L1 + L2 + L3 + L4+
								L5 + L6 + L7 + a + b + c + d + e + f + g + h + i + j
	Farthest piping length L (*)			Actual length			150 m	LA + LB + Ld + L1 + L3 + L4 + L5 + L6 + j
				Equivalent length			175 m
	Equivalent length of farthest piping from 1st branching Li (*)						65 m	L3 + L4 + L5 + L6 + j
	Equivalent length of farthest piping between outdoor units LO (*)						25 m	LA + LB + Ld, (LA + Lb, LA + LB + Lc)
	Max. equivalent length of main piping (***)						85 m	L1
	Max. equivalent length of outdoor unit connection piping						10 m	Ld, (La, Lb, Lc)
	Max. actual length of indoor unit connection piping						30 m	a, b, c, d, e, f, g, h, i, j
Height difference	Height between indoor			Upper outdoor unit			50 m	——
	and outdoor units H1			Lower outdoor unit			40 m (**)	——
	Height between indoor units H2						30 m	——
	Height between outdoor units H3						5 m	——

*(D) is outdoor unit farthest from 1st branching, and ( j ) is indoor unit farthest from 1st branching.

** If the height difference (H2) between indoor units exceeds 3 m, set below 30 m.

*** If the maximum combination capacity of the outdoor units is 46 hp or more, the maximum equivalent length is restricted up to 70 m.

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