Determining The Total System Charge - LG Multi IV Engineering Manual

Figure 26: LATS Tree Diagram for Multi V IV Heat Recovery System Test Update System No: 1/1 Example.
Determining the Total System Charge (Refer to Table 49)
1. Using the LATS Tree diagram, document the linear feet of straight liquid piping and the quantity and type of each fitting by pipe diameter
into System Refrigerant Charge Calculator.
2. Calculate the total linear feet of liquid line piping in the system. It is imperative to know the "as-built" physical length of each segment of
liquid line to calculate the total refrigerant charge required. An accurate "as built" field-verified piping diagram is required to verify within
LATS that piping is within limits, proper pipe sizing, and refrigerant charge. Record the values on lines 1–7.
3. Count the number of indoor units. Group them by model type and nominal capacity as indicated in the description field on lines 8–38.
Record the quantity of units in each group, multiply each by their specific correction factor, and add the sum in the Total (lbs.) column.
4. Count the number of heat recovery units, record the quantity, multiply by the specific correction factor, and record the sum in the Total
(lbs.) column on line 39.
5. Sum the total values on lines 1-39 and place in the field labeled "Additional Refrigerant Charge Required" on line 40.
6. Record the quantity of each outdoor unit frame, multiple total of each by their specific correction factor on lines 41a-g, and enter the total
on line 42 (Total Factory Refrigerant Charge).
7. Add the Additional Refrigerant Charge Required to the Total Factory Refrigerant Charge. This is the Total System Charge. Record on line
43.
REFRIGERANT PIPING DESIGN
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