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70
60
50
40
30
20
10
0
-20
Step 6—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 7—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- - and return- -air grilles are open and free from
obstructions, and that the air filter is clean.
Step 8—Metering Devices- -TXV & Accurater Piston
This unit uses 2 types of metering devices. The outdoor metering
device is a fixed orifice and is contained in the brass- -hex body in the
liquid line feeding the outdoor coils. The indoor metering device is
a TXV- -type device.
Step 9—Pressure Switches
Pressure switches are protective devices wired into control circuit
(low voltage). They shut off compressor if abnormally high or low
pressures are present in the refrigeration circuit. These pressure
switches are specifically designed to operate with Puron (R- -410A)
systems. R- -22 pressure switches must not be used as replacements
for the Puron (R- -410A) system.
Balance Point Worksheet
Based on Entering Indoor Air of 70 Deg. F and Rated CFM
-10
0
10
Outdoor Air Temp (Deg F)
Fig. 25 - - 50CR Balance Point Worksheet
20
30
40
50
Fig. 26 - - Refrigerant Circuit
Step 10—Loss- -of- -Charge Switch
This switch is located on the liquid line and protects against low
suction pressures caused by such events as loss of charge, low
26
060
048
042
036
030
024
60
C03008
C99097
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