Technical Data Manual

Design of Mini VRF SYSTEM

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1. Model Selecting and Capacity Calculator

For U-36LE1U6(E) units

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If the maximum tubing length (L1) exceeds 295 ft. (equivalent length), increase the tubing size of the main gas

tube (LM) by one rank.

* The size increase is applied to the gas tube only. In addition, for a 6 HP unit it is not necessary to increase the

tubing size.

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Increasing the tubing size of the gas tubes can reduce the loss of capacity caused by longer tubing lengths.

Refer to Table 2-1 to increase the tubing size. However, the maximum allowable tubing length must not be

exceeded.

* The size increase is applied to the LM gas tube (main tube with the largest diameter) only, and is limited to the

cases shown in Table 2-1. In addition, the amount of additional refrigerant charge is determined from the liquid

tube size only.

* In case of 6

pieces, increasing the size of the gas tube is not possible.

Table 2-1 Correction coefficient for equivalent length when the size of the gas tube (LM) is increased

ø5/8" (ø15.88)

ø3/4" (ø19.05)

0.4

* When increasing the size of the gas tubing (LM), multiply by the correction coefficient from Table 2-1 and calculate the

equivalent length for section LM.

Tubing equivalent length after size increase = Standard tubing equivalent length × Equivalent length correction coefficient

Tube diameter after change (gas tube, in. (mm))

Equivalent length correction coefficient

Standard tube diameter (gas tube, in. (mm))

The upper limit for tubing size is ø3/4” (ø19.05). Tubing above that size cannot be

used.

WARNING

TD831156-00_MINI_VRF_SYS.indb 12TD831156-00_MINI_VRF_SYS.indb 12 2012/01/31 14:38:442012/01/31 14:38:44