Charging - Lennox HPXA15-024 Installation Instructions Manual

Charging

This system is charged with R410A refrigerant which oper-
ates at much higher pressures than R22. The check/ex-
pansion valve provided with the unit is approved for use
with R410A. Do not replace it with a valve designed for use
with R22. This unit is NOT approved for use with coils which
include metering orifices or capillary tubes.
Processing Procedure
The unit is factory−charged with the amount of R410A re-
frigerant indicated on the unit rating plate. This charge is
based on a matching indoor coil and outdoor coil with a 15
foot (4.6 m) line set. For varying lengths of line set, refer to
table 2 for refrigerant charge adjustment.
Table 2
Liquid Line Set Oz. per 5 ft. (grams per 1.5 m) adjust
Diameter
3/8 in.
(10 mm)
*If line length is greater than 15 ft. (4.6 m), add this amount.
If line length is less than 15 ft. (4.6 m), subtract this amount.
IMPORTANT
Mineral oils are not compatible with R410A. If oil
must be added, it must be a polyol ester oil.
The compressor is charged with sufficient polyol ester
oil for line set lengths up to 50 feet (15.2 m). Do not add
any more than 7 oz. of oil.If oil must be added to the
compressor in the field, Copeland has approved Mobil
EALt Arctic 22CC and ICI EMKARATEt RL32CF.
The outdoor unit should be charged during warm weather.
However, applications arise in which charging must occur
in the colder months. The method of charging is deter-
mined by the unit's refrigerant metering device and the out-
door ambient temperature.
Measure the liquid line temperature and the outdoor ambi-
ent temperature as outlined below:
1 − Close manifold gauge set valves. Connect manifold
gauge set to service valves as shown in figure 16:
low pressure gauge to vapor valve service port
D
high pressure gauge to liquid valve service port
D
Connect the center manifold hose to an upright cylin-
der of R410A .
2 − Set the room thermostat to call for heat. This will create
the necessary load for properly charging the system in
the cooling cycle.
3 − Use a digital thermometer to record the outdoor ambi-
ent temperature.
4 − When the heating demand has been satisfied, switch
the thermostat to cooling mode with a set point of 68_F
(20_C). When pressures have stabilized, use a digital
thermometer to record the liquid line temperature.
from 15 ft. (4.6 m) line set*
3 ounces per 5 feet
(85g per 1.5 m)
5 − The outdoor temperature will determine which charg-
ing method to use. Proceed with the appropriate charg-
ing procedure.
Weighing in the Charge TXV Systems –
Outdoor Temp < 65_F (18_C)
If the system is void of refrigerant, or if the outdoor ambient
temperature is cool, the refrigerant charge should be
weighed into the unit. Do this after any leaks have been re-
paired.
1 − Recover the refrigerant from the unit.
2 − Conduct a leak check, then evacuate as previously
outlined.
3 − Weigh in the unit nameplate charge.
If weighing facilities are not available or if you are charging
the unit during warm weather, follow one of the other proce-
dures outlined below.
Subcooling Method
Outdoor Temp. < 65°F (18°C)
When the outdoor ambient temperature is below 65°F
(18°C), use the subcooling method to charge the unit. It
may be necessary to restrict the air flow through the out-
door coil to achieve pressures in the 325−375 psig
(2240−2585 kPa) range. These higher pressures are nec-
essary for checking the charge. Block equal sections of air
intake panels and move obstructions sideways until the liq-
uid pressure is in the 325−375 psig (2240−2585 kPa) range.
See figure 15.
1 − With the manifold gauge hose still on the liquid service
port and the unit operating stably, use a digital ther-
mometer to record the liquid line temperature.
2 − At the same time, record the liquid line pressure reading.
3 − Use a temperature/pressure chart for R410A to deter-
mine the saturation temperature for the liquid line pres-
sure reading. See table 6.
4 − Subtract the liquid line temperature from the saturation
temperature (according to the chart) to determine sub-
cooling. (Saturation temperature − Liquid line tem-
perature = Subcooling)
5 − Compare the subcooling value with those in table 3. If
subcooling is greater than shown, recover some refrig-
erant. If subcooling is less than shown, add some re-
frigerant. Be aware of the R410A refrigerant cylinder. It
Page 15
Blocking Outdoor Coil
Outdoor coil should be
blocked one side
at a time with cardboard
or plastic sheet until proper
testing pressures
are reached.
cardboard or
plastic sheet
Figure 15