Example Of Tubing Size Selection And Refrigerant Charge Amount - Panasonic U-36LE1U6 Installation Instructions Manual

1-13. Example of Tubing Size Selection and Refrigerant Charge Amount

Additional refrigerant charging
Based on the values in Tables 1-2, 1-3, 1-4 and 1-7, use the liquid tubing size and length, and calculate the amount
of additional refrigerant charge using the formula below.
Required additional
= 0.602 × (a) + 0.279 × (b)
refrigerant charge (oz)
(a): Liquid tubing Total length of ø3/8" (ft.)
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Charging procedure
Be sure to charge with R410A refrigerant in liquid form.
1. After performing a vacuum, charge with refrigerant from the liquid tubing side. At this time, all valves must be
in the "fully closed" position.
2. If it was not possible to charge the designated amount, operate the system in Cooling mode while charging
with refrigerant from the gas tubing side. (This is performed at the time of the test run. For this, all valves
must be in the "fully open" position.)
Charge with R410A refrigerant in liquid form.
With R410A refrigerant, charge while adjusting the amount being fed a little at a time in order to prevent
liquid refrigerant from backing up.
●
After charging is completed, turn all valves to the "fully open" position.
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Replace the tubing covers as they were before.
Tightening torque for valve stem cap: 160 – 180 lbs · in.
Tightening torque: 300 – 360 lbs · in.
1. R410A additional charging absolutely must be done through liquid charging.
CAUTION
2. The R410A refrigerant cylinder has a gray base color, and the top part is pink.
3. The R410A refrigerant cylinder includes a siphon tube. Check that the siphon
tube is present. (This is indicated on the label at the top of the cylinder.)
4. Due to differences in the refrigerant, pressure, and refrigerant oil involved in
installation, it is not possible in some cases to use the same tools for R22 and
for R410A.
(b): Liquid tubing Total length of ø1/4" (ft.)
4 1 Tightening torque: 590 – 710 lbs · in.
3
2 Tightening torque for valve stem cap: 240 – 280 lbs · in.
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