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(open) at 25 + 5 psi. The switch automatically resets when
suction line pressure rises above 40 + 5 psi. Under certain
conditions the low pressure switch is ignored. See Pres-
sure Switch Circuit in the Defrost Control description.
G − Drier
A filter drier designed for all 13HPX 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 compressor 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
R−410A 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. To safeguard against moisture entering the
system follow the steps in section III − sub section
C − "Evacuating the System" when replacing the drier.
H − Crankcase Heater HR1 & Thermostat
S40 (options)
Crankcase heater HR1 is an option for all size units, while
thermostat S40 is an option for 5 ton units only. HR1 is a 40
watt heater that prevents liquid from accumulating in the
compressor. In the 13HPX−060 (5 ton unit) HR1 is con-
trolled by thermostat S40 located in the liquid line. When
liquid line temperature drops below 50° F, S40 closes ener-
gizing HR1. S40 will open once liquid line temperature
reaches 70°, de−energizing HR1.
TABLE 2
KIT CONTENTS
TUBE SHELF
LIFE
10N46 − Refrig-
erant Analysis
Checkmate−RT700
10N45 − Acid
Test Tubes
Checkmate−RT750A (three
pack)
2 − 3 years @
room tempera-
ture. 3+ years re-
frigerated
10N44 − Mois-
ture Test Tubes
Checkmate − RT751 Tubes
(three pack)
6 − 12 months @
room tempera-
ture. 2 years re-
frigerated
74N40 − Easy
Oil Test Tubes
Checkmate − RT752C Tubes
(three pack)
2 − 3 years @
room tempera-
ture. 3+ years re-
frigerated
74N39 − Acid
Test Kit
Sporian One Shot − TA−1
II − REFRIGERANT SYSTEM
FIGURE 10
13HPX COOLING CYCLE (SHOWING MANIFOLD GAUGE CONNECTIONS)
OUTDOOR
COIL
DEFROST THERMOSTAT
EXPANSION/CHECK
VALVE
BIFLOW
FILTER / DRIER
TO
R−410A
DRUM
LOW
PRESSURE
HIGH
PRESSURE
COMPRESSOR
REVERSING VALVE
VAPOR
LINE
VALVE
MUFFLER
NOTE − ARROWS INDICATE DIRECTION OF REFRIGERANT FLOW
SERVICE
PORT
SUCTION
EXPANSION/CHECK
VALVE
INDOOR UNIT
OUTDOOR UNIT
LIQUID LINE
SERVICE
PORT
GAUGE MANIFOLD
DISTRIBUTOR
INDOOR
COIL
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