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F − Drier
A filter drier designed for all HPXA12 model units is factory
installed in the liquid line. The filter drier is designed to re-
move moisture and foreign matter, which can lead to com-
pressor failure.
Moisture and / or Acid Check
Because POE oils absorb moisture, the dryness of the
system must be verified any time the refrigerant sys-
tem is exposed to open air.
A
c
ompressor oil sample must
be taken to determine if excessive moisture has been
introduced to the oil. Table 2 lists kits available from Lennox
to check POE oils.
If oil sample taken from a system that has been exposed to
open air does not test in the dry color range, the filter drier
MUST be replace.
IMPORTANT
Replacement filter drier MUST be approved for
R410A refrigerant and POE application.
Foreign Matter Check
It is recommended that a liquid line filter drier be replaced
when the pressure drop across the filter drier is greater than
4 psig.
G − High/Low Pressure Switch
IMPORTANT
Pressure switch settings for R410A refrigerant will
be significantly higher than units with R22.
An auto-reset, single-pole/single-throw high pressure switch
is located in the liquid line. This switch shuts off the compres-
sor when liquid line pressure rises above the factory setting.
The switch is normally closed and is permanently adjusted to
trip (open) at 640 + 10 psi.
An auto-reset, single-pole/single-throw low pressure
switch is located in the suction line. This switch shuts off the
compressor when suction pressure drops below the factory
setting. The switch is closed during normal operating pres-
sure conditions and is permanently adjusted to trip (open)
at 25 + 5 psi. The switch automatically resets when suction
line pressure rises above 60 + 5 psi.
TABLE 2
KIT
CONTENTS
TUBE SHELF LIFE
10N46 − Refrigerant Analysis
Checkmate−RT700
10N45 − Acid Test Tubes
Checkmate−RT750A (three pack)
2 − 3 years @ room temperature. 3+
years refrigerated
10N44 − Moisture Test Tubes
Checkmate − RT751 Tubes (three
pack)
6 − 12 months @ room temperature. 2
years refrigerated
74N40 − Easy Oil Test Tubes
Checkmate − RT752C Tubes (three
pack)
2 − 3 years @ room temperature. 3+
years refrigerated
74N39 − Acid Test Kit
Sporian One Shot − TA−1
