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Rain shield location is critical on the condenser fan assem-
bly. Installing the shields to close to the bearing hub will
create noise and may affect operation. Installing too far
away will allow moisture to enter the bearing resulting in
motor failure. See figure 16 .
FIGURE 16
plastic
shield
fiber
shield
RAIN SHIELD LOCATION
(−038 only)
3"
Critical
Dimension
Troubleshooting
If first or second stage thermostat call for cool is present
and the variable speed condenser fan motor does not ener-
gize, check voltage at the breaker box. If voltage is present
do the following and reference figure 17.
1− Check for 240 volts between the compressor RED wi-
res.
2− Initiate a first stage call for cool. Check for 24 volts be-
tween the fan motor YELLOW wire and fan motor
BLACK wire.
3− Initiate a second stage call for cool. Check for 24 volts
between the fan motor YELLOW wire and fan motor
BLACK wire, then check for 24 volts between the fan
motor BLUE wire and fan motor BLACK.
4− Repeat steps 1 through 3 with a HEAT call.
FIGURE 17
RED
RED
240V
YELLOW
BLUE
BLACK
common
1st Stage (low capacity − 700 rpm)
2nd Stage (High capacity − 820 rpm)
B4
24V
Y1
Y2
RED
RED
YELLOW
BLUE
BLACK
B4
240V
24V
common
Y2
Y1
24V
0V
24V
24V
240V
240V
S−Filter Drier
A filter drier designed for all HPXA19 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 4 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 replaced.
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.
T−Accumulator (HPXA19−060 only)
ALL 5 ton HPXA19 units are equipped with an accumulator.
The purpose of the accumulator is to trap and evaporate all
liquid refrigerant returning to the compressor.
U−Charge Compensator
HPXA19−038 and −048 series units are equipped with a
charge compensator located in the vapor line between the
reversing valve and outdoor coil manifold. The compensa-
tor is used to collect and store excess refrigerant in the
heating mode. Figure 18 shows operation of the charge
compensator.
In heating mode, the vapor line passing through the charge
compensator tank is cooler than the liquid line. Excess re-
frigerant (condensed liquid) from the indoor coil is trapped
by the compensator. The vapor line is cooler than the liquid
line so liquid migrates from the liquid line to the compensa-
tor tank where it is stored. In cooling mode, the vapor line
passing through the charge compensator tank is hotter
than the liquid line. Stored liquid is boiled and forced back
into the liquid line for circulation.
