Application Guidelines

For dual fuel systems, the furnace must have a suitable blower size. Indoor coils
built in 2006 or newer may be straight matched to the outdoor unit tonnage or
one size larger*. An R410A refrigerant TXV is required on the indoor coil. Indoor
coils built between 2005 and 1992 must be one or two tonnage sizes larger than
the outdoor unit tonnage*. An R410A TXV must be added to the indoor coil.
Existing 2-stage indoor equipment
The ICP inverter is capable of operating with a standard 2-stage thermostat and
non-communicating 2-stage indoor equipment. In this case, the outdoor unit will
be wired as a 2-stage system, and will operate as a 2-stage system. Combination
ratings will be available with FVM4 fan coils and some furnace/coil combinations.
These ratings will apply to both new and existing equipment of like model
numbers.
NOTE: In replacement situations, the 24, 25, and 36 size ICP inverter models
are NOT compatible with the FEM4X60, or FVM4X60.
For existing dual fuel systems, the furnace must have a suitable blower size and
staging capability. Indoor coils built in 2006 or newer may be straight matched to
the outdoor unit tonnage or one size larger*. A R410A TXV is required on the
indoor coil. Furnace coils built between 2005 and 1992 must be one or two
tonnage sizes larger than the outdoor unit tonnage*, and a R410A TXV must be
added to the suitable indoor coil.
Set furnace high stage airflow at 350-400 cfm/ton
Set furnace low stage airflow at 70-80% of high stage
* Examples
 Straight matched to outdoor unit tonnage- 3-ton ICP inverter unit with 3-ton furnace or fan coil
 One size larger indoor – 3-ton ICP inverter with 3.5 ton furnace or fan coil
 2 sizes larger indoor – 3-ton ICP inverter with older 4 ton furnace coil