Multizone Outdoor Unit Installation Manual

Revised 5/14/2020
Line length
(feet)
Subtract
pre-charge
Length minus
pre-charge
Calculate addition-
al refrigerant
Add this much re-
frigerant to your
system
BM18M 2 zone
Zone B
Zone A
Total -50 x 0.16
ozs
BM27M 3 zone
Zone C
Zone B
Zone A
Total -75 x 0.16
ozs
BM36M 4 zone
Zone D
Zone C
Zone B
Zone A *if 24k, x2
Total -100 x 0.16
ozs
BM48M 5 zone
Zone E
Zone D
Zone C
Zone B *if 24k, x2
Zone A *if 24k, x2
Total -125 x 0.16
ozs
*Note: For 24k air handlers using 3/8" - 5/8" lineset, double the length.
Example: if the 24k line length is 15', enter 30'.
Note On Adding Refrigerant
Air Evacuation
CAUTION
• Refrigerant charging must be performed after wiring, leak testing and vacuuming.
• DO NOT exceed the maximum allowable quantity of refrigerant or overcharge the system.
Doing so can damage the unit or impact it’s functioning.
• Charging with unsuitable substances may cause explosions or accidents. Ensure that the
appropriate refrigerant is used.
• Refrigerant containers must be opened slowly. Always use protective gear when charging
the system.
• DO NOT mix refrigerants types.
 Page 22 
Table 9.1 Refrigerant Chart
Directions:
1. Find your condenser model below.
2. Enter lineset length for each connected zone - calculate total.
3. Subtract your unit's pre-charge from the total.
4. If the result is negative, system is fully charged, do nothing.
5. If result is positive. multiply by 0.16.
6 This is how much to add.