Johnson Controls (H,Y)VAHP072B31CW, Installation And Maintenance Manual

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8.4 Additional Refrigerant Charge Calculation
Table 8.1 Additional Refrigerant Charge Calculation
No. Symbol Contents
Additional
Charge
1 W1
1 Additional Refrigerant Charge Calculation for Liquid Piping (W1 lbs)
Pipe Diameter
inch (mm)
Total Piping Length
(ft)
Refrigerant Amount for
1 ft Pipe
Additional Charge
(lbs)
7/8 (22.2) × 0.24 =
3/4 (19.05) × 0.17 =
5/8 (15.88) × 0.11 =
1/2 (12.7) × 0.074 =
3/8 (9.52) × 0.038 =
1/4 (6.35) × 0.016 =
Total Additional Charge For Liquid Piping =
2 Minimum Additional Refrigerant Change for Liquid Piping (lbs)
Outdoor Unit Type (x 1,000 Btu/h) 72 96 144 168 192 288
Minimum Additional Refrigerant Charge 4.4 4.4 8.8 8.8 8.8 13.2
In case the calculated quantity ( 1 ) is less than the minimum quantity ( 2 ) then add 2 as
the additional refrigerant charge quantity for liquid piping (W1).
lbs
2 W2 Depending on connection of indoor unit type, additional refrigerant charge is required.
Select adequate refrigerant amount from the table below.
Additional Refrigerant Charge for Each Indoor Unit Connected (W2 lbs)
Capacity (x 1,000 Btu/h) 6 8 12 15 18 24 30 36 48
Indoor Unit
Type
(H,Y)IDM***B21S 0 0 0.26 0.35 0.55 0.66 1.1 0
(H,Y)IC4***B21S - - 0.55 1.1 -
NOTE:
Maximum additional refrigerant charge must not exceed 4.4 lbs.
lbs
3 W3 Calculation Method for Additional Refrigerant Charge (W3 lbs)
If the capacity of combined Indoor Unit is larger than 072 MBH, the additional refrigerant
charge must be 2.2 lbs/unit.
× 2.2 lbs/unit =
lbs
4 W4 The Ratio of Indoor Unit Connection Capacity (Indoor Unit Total Capacity/Outdoor Unit
Capacity) Additional Charge (W4 lbs)
Determine the ratio of indoor unit connection capacity.
Condition Refrigerant Amount
I.U. Capacity Ratio is less than 100% 0.0 lbs
I.U. Capacity Ratio is 100% or more 1.1 lbs
lbs
5 WT
Calculation of Additional Charge (WT lbs) =
W1 + W2 + W3 + W4 =
NOTE:
When the total capacity of the following indoor unit connected is 50% or more of the outdoor
unit capacity, then add
1.2 times
of the above total additional refrigerant charge (WT).
Ɣ 4-Way Cassette Type: (H,Y)IC4***B21S
Ɣ 1-Way Cassette Type: (H,Y)IC1***B21S
Ɣ Wall Mount Type: TIWM***B21S
lbs
NOTE:
Ensure that the total additional charge WT does not exceed the maximum additional refrigerant charge quantity
as shown in the table on the following page.
Although this unit has been charged with refrigerant, an additional refrigerant charge is required according to
piping length.
Determine what additional quantity of refrigerant according to the following procedures, and charge it into the
system. Record the additional refrigerant quantity to facilitate maintenance and servicing activities thereafter.
(1) Calculating Method of Additional Refrigerant Charge (WT lbs)