Lennox 13ACX Installation And Service Procedure page 31

START: Measure outdoor ambient temperature
USE WEIGH‐IN METHOD DO NOT CHARGE UNIT
(Results of charging at low
Weigh‐in or remove refriger­
temperatures not reliable)
ant based upon line length
APPROACH TXV
If refrigerant is added
or removed, retest to
confirm that unit is
properly charged.
If value is greater than
shown (high approach),
add refrigerant; if less
than shown (liquid
temperature too close to
ambient temperature,
low approach), remove
refrigerant.
START: Measure outdoor ambient temperature
USE WEIGH‐IN METHOD
DO NOT CHARGE UNIT
Weigh‐in or remove refrigerant
(Results of charging at low
based upon line length
temperatures not reliable)
SUBCOOLING TXV
If refrigerant is
If value is
added or removed,
MORE than
verify charge using
shown, remove
the Approach
refrigerant.
Method.
If value is LESS
MORE or
than shown, add
LESS
refrigerant.
ABOVE or
BELOW
64ºF
(17.7ºC) and
Below
See Table 4 on page 33 to determine
which charging sticker to use.
Figure 20. HFC-410A Approach TXV Charge
(18.3ºC) and
ABOVE or
BELOW
64ºF
(17.7ºC) and
Below
BLOCK OUTDOOR COIL: [sometimes necessary with
lower temperatures] Use cardboard or plastic sheet to
restrict the airflow through the outdoor coil to achieve
pressures from 325-375 psig (2240-2585 kPa). Higher
pressures are needed to check charge. Block equal
sections of air intake panels and move coverings sideways
until the liquid pressure is in the above noted ranges.
CARDBOARD OR PLASTIC SHEET
See Table 4 on page 33 to determine
Figure 21. HFC-410A Subcooling TXV Charge
1. Confirm proper airflow across coil using figure 17.
65ºF
2. Compare unit pressures with normal operating
(18.3ºC) and
Above
3. Set thermostat to call for heat (must have a cooling
4. Connect gauge set.
5. When heat demand is satisfied, set thermostat to
6. Allow temperatures and pressures to stabilize.
7. Record outdoor ambient temperature:
8. Record liquid line temperature:
9. Subtract to determine approach (APPº):
10. Compare results with table below.
1. Confirm proper airflow across coil using figure
65ºF
2. Compare unit pressures with normal operating
Above
3. Set thermostat to call for heat (must have a
4. Connect gauge set
5. Measure outdoor ambient temperature
6. When heat demand is satisfied, set thermostat to
7. Allow temperatures and pressures to stabilize.
8. Record liquid line temperature:
9. Measure liquid line pressure and use the value to
10. Subtract to determine subcooling (SCº):
11. Compare results with table below.
which charging sticker to use.
Page 31
pressures provided on applicable charging sticker
as reference in table 4..
load between 70‐80ºF (21-26ºC).
call for cooling.
AMBº =_________
LIQº = __________
LIQº_____ - AMBº _____ = APPº_____
17.
pressures provided on applicable charging
sticker as reference in table 4.
cooling load between 70‐80ºF (21-26ºC)
call for cooling
NOTE - If necessary, block outdoor coil to
maintain 325 - 375 psig.
LIQº = ______
determine saturation temperature (see table 3):
SATº = ______
SATº_____ - LIQº _____ = SCº _____
13ACX
SERIES