Application Guidelines

Existing 1-stage indoor equipment
The ICP inverter will work with a 1-stage thermostat as a 1-stage system with suitable
indoor coil and fan until the indoor components can be upgraded to provide full variable
speed functionality.
If the indoor furnace coil was built in 2006 or after, it may be straight matched or one
size larger than the outdoor unit tonnage*. If the furnace coil was built between 2005
and 1992, the furnace coil may be straight matched, one or two sizes larger than the
outdoor unit tonnage*. An R410A TXV is required on the indoor coil.
In existing fan coil applications, if the unit was built in 2006 or after, it may be straight
matched or one size larger than the outdoor unit tonnage*. If the fan coil was built
between 2005 and 1992, it may be straight matched, or one size larger tonnage than
the outdoor unit tonnage*. An R410A refrigerant TXV is required on the indoor coil.
Line set limitations
The ICP Inverter unit is qualified for line sets up to 100ft. equivalent length
Lift limitations:
Outdoor above indoor: 100 ft.
Outdoor below indoor:
2 ton
3 ton
4 ton
5 ton
80ft
80ft
70ft
60ft
See Product Specifications for line set diameter requirements
Sound
The ICP inverter unit uses a pressure equalizer valve (see Figure 1). It is designed to
equalize pressures across the rotary compressor in the off-cycle to ensure easier
starting. During the equalization process, a hissing sound may be heard by customers.
This sound is normal, but the customer should be made aware to avoid nuisance
callbacks.
Figure 1. Pressure Equalizer Valve
*Examples
• Straight matched to outdoor unit tonnage – 3-ton AC unit with 3-ton furnace or fan coil
• One size larger indoor – 3-ton AC with 3.5 ton furnace or fan coil
• 2 sizes larger indoor – 3-ton AC with older 4 ton furnace coil