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4-3-2. Correcting Capacity for Changes in the Length of Refrigerant Piping
(1) During cooling, to obtain the ratio (and the equivalent piping length) of the outdoor units rated capacity and the total
in-use indoor capacity, first find the capacity ratio corresponding to the standard piping length (5m) from figures 5 and 6
at first, and then multiply by the cooling capacity from Figure 1 to obtain the actual capacity.
(2) During heating, to find the equivalent piping length, first find the capacity ratio corresponding to standard piping length
(5m) from Figure 7, and then multiply by the heating capacity from Figure 2 to obtain the actual capacity.
(1) Cooling capacity correction factor
Figure 5. PUMY-71VM, PUMY-71VM
1
, PUMY-71VM
2
Cooling capacity correction curve
(2) Heating capacity correction factor
Figure 7. PUMY Series Heating capacity correction curve
1.0
0.9
0.8
0.7
0
10
20
30
40
50
60
70
35 (50%)
53 (75%)
71 (100%)
93 (130%)
Total capacity of indoor unit
Cooling
Capacity
(ratio)
piping length (m)
(3) Method for Obtaining the Equivalent Piping Length
Equivalent length for type 125 = (length of piping to farthest indoor unit) + (0.35
o
number of bends in the piping) (m)
Length of piping to farthest indoor unit: type 125.....70m
4-3-3. Correction of Heating Capacity for Frost and Defrosting
If heating capacity has been reduced due to frost formation or defrosting, multiply the capacity by the appropriate correction
factor from the following table to obtain the actual heating capacity.
Correction factor diagram
6
1.0
-10
0.95
-8
0.95
-6
0.95
-4
0.9
-2
0.89
0
0.88
2
0.89
4
0.98
Outdoor Intake temperature (°CWB)
Correction factor
Figure 6. PUMY-125VM, PUMY-125VM
1
, PUMY-125VM
2
, PUMY-125YM, PUMY-125YM
1
, PUMY-125VMA, PUMY-125VMA
1
PUMY-125YMA
Cooling capacity correction curve
1.0
0.95
0.9
5 10
20
30
40
50
60
70 75
Heating
Capacity
(ratio)
1.0
0.9
0.9
0.7
63 (50%)
94 (75%)
125 (100%)
163 (130%)
5 10
70
20
30
40
50
60
75
Cooling
Capacity
(ratio)
Total capacity for indoor unit
piping equivalent length (m)
piping equivalent length (m)
OC183E--2.qxp 10.5.6 0:46 PM Page 33
