International comfort products PH4E Series, Installation Instructions Manual, Page: 19 / 24

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FIGURE 17 Typical Heat Pump Operation, Cooling Mode
COMPRESSOR
ACCUMULATOR
OUTDOOR COIL
INDOOR COIL
LCS
LEGEND
HPS – High Pressure Switch
LCS – Loss of Charge Switch
Accurater ® Metering De vice
Arrow indicates direction of flo w
TXV in Metering
Position
Bypass
Position
HP S
FIGURE 18 Typical Heat Pump Operation, Heating Mode
COMPRESSOR
ACCUMULATOR
OUTDOOR COIL INDOOR COIL
LCS
LEGEND
HPS – High Pressure Switch
LCS – Loss of Charge Switch
Accurater ® Metering De vice
Arrow indicates direction of flo w
Position
HP S
TXV in Bypass
Metering
Position
Step 5 — Refrigerant Circuit
Inspect all refrigerant tubing connections and the unit base for oil
accumulation annually. Detecting oil generally indicates a
refrigerant leak.
If oil is detected or if low performance is suspected, leak
− test all
refrigerant tubing using an electronic leak detector, or
liquid − soap solution. If a refrigerant leak is detected, refer to
Check for Refrigerant Leaks section.
If no refrigerant leaks are found and low performance is
suspected, refer to Checking and Adjusting Refrigerant Charge
section.
Step 6 — Indoor Airflow
The heating and/or cooling airflow does not require checking
unless improper performance is suspected. If a problem exists,
be sure that all supply − air and return − air grilles are open and
free from obstructions, and that the air filter is clean. When
necessary, refer to Indoor Airflow and Airflow Adjustments
section to check the system airflow.
Step 7 — Metering Device − Piston
This unit uses a fixed orifice metering device for both cooling and
heating modes.
FIGURE 19 Refrigerant Circuit