Application Guidelines

Another sound that may be heard by customers is the equalization of pressures during
the off-cycle. This unit contains a pressure equalizer valve that is designed to allow
easier starting of the rotary compressor (see Figure 1 below). It will energize in the off-
cycle to equalize pressure across the compressor. A hissing sound may be heard
during this process. This sound is normal, but the customer should be made aware to
avoid nuisance callbacks.
Figure 1. Pressure Equalizer Valve
To avoid sound complaints, the following guidelines should always be followed:
Sound DO’s
1. Explain the sound range to the customer so that they understand the
differences they will hear throughout the year. The higher speeds in heating,
while happening for minimal time periods, help produce comfortable and
efficient heating during times of more extreme cold.
2. Explain the defrost cycle to customers. The ICP inverter heat pump has a
defrost cycle like any heat pump and the sound may be noticeable during
winter months. Explain that this is normal for heat pump and required for
efficient operation
3. Explain the equalization sound described above to customers to avoid
nuisance callbacks.
Sound Don’ts
1. Do not install this heat pump, or any other heat pump, outside bedroom
windows. The defrost cycle will likely be heard through the window during
winter and my cause customer complaints
2. Due to the wide operating range of this unit in heating mode, it is particularly
important to follow published installation guidelines regarding refrigerant lines.
Do not attach refrigerant piping to structural joists or beams in the home. This
can transmit vibration and sound into the home which can cause customer
complaints. If the lineset is hard mounted to structural members, an
accessory vapor line muffler is recommended to minimize transmitted sound.
See Product Data for muffler part number.