Lennox HP40, Installation Instructions Manual

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Page 10
7 − Recheck the unit voltage while the unit is running.
The power must be within the range shown on the
unit nameplate. Check the amperage draw of the
unit. Refer to the unit nameplate for approximate
running amps.
Charging
Liquid charge the unit with the amount of R407C refriger-
ant that is indicated on the nameplate.
IMPORTANT
If existing refrigerant lines which were previously
charged with R22 are going to be used, they must
first be flushed of existing mineral oil. Take care
to empty all existing traps. Polyol ester (POE) oils
are used in Lennox units charged with R407C re-
frigerant. Mineral oils are not compatible with
polyol ester oils.
This charge is based on a matching indoor coil and out-
door coil with a 4.6 m line set. For varying lengths of line
set, refer to table 2 for refrigerant charge adjustment.
TABLE 2
Liquid Line
Set Diameter
g per 1524 mm adjust
from 4.6 m line set*
8 mm 57 g per 1524 mm
10 mm 85 g per 1524 mm
*If line length is greater than 4.6 m, add this amount.
If line length is less than 4.6 m, subtract this amount.
Charging Using the Subcooling Method
If the outdoor ambient temperature is below 13 C, airflow
over the outdoor coil will need to be reduced to drive up
the liquid line pressure to a range of 1379 to 1724 kPa. To
do this, block off the outdoor coil with cardboard or a plas-
tic sheet.
BLOCKING OUTDOOR COIL
CARDBOARD OR
PLASTIC SHEET
OUTDOOR COIL SHOULD
BE BLOCKED ONE SIDE
AT A TIME WITH CARD−
BOARD OR PLASTIC
SHEET UNTIL PROPER
TESTING PRESSURES
ARE REACHED.
FIGURE 9
1 − Remove the cap from the liquid line service valve
stem and turn the stem clockwise 1/4 to 1/2 turn. This
will open the service port.
2 − With the manifold gauge hose still on the liquid ser-
vice port and the unit operating, read the liquid line
pressure.
3 − If the pressure is too low, block the airflow through
the outdoor coil until the liquid line pressure stabi-
lizes in a range from 1379 to 1724 kPa. At that time,
record the liquid line temperature and the liquid line
pressure reading.
4 − Use a temperature/pressure chart for R407C to de-
termine the saturation temperature for the liquid line
pressure reading.
5 − Subtract the liquid line temperature from the satura-
tion temperature (according to the chart) to determine
subcooling.
(Saturation temperature − Liquid line
temperature = Subcooling.) Subcooling should
be between 4.4−5.5°C.
If subcooling is greater than
4.4 − 5.5°C, recover some refrigerant. If subcooling is
less than 4.4 − 5.5°C, add some refrigerant.