Lennox ML14XC1 Series Manual page 29

START: Measure outdoor ambient temperature
USE WEIGH IN METHOD DO NOT CHARGE UNIT
(Results of charging at low
ant based upon line length temperatures not reliable)
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
FIGURE 21. HFC-410A Approach TXV Charge
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
FIGURE 22. HFC-410A Subcooling TXV Charge
1. Confirm proper airflow across coil using figure
65ºF
(18.3ºC) and
2. Compare unit pressures with normal operating
Above
3. Set thermostat to call for heat (must have a
4. Connect gauge set.
5. When heat demand is satisfied, set thermostat
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 applicable charging
1. Confirm proper airflow across coil using figure
65ºF
2. Compare unit pressures with normal operating
(18.3ºC) and
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 applicable charging sticker
Page 29
19.
pressures provided on applicable charging
sticker as reference in table 1.
cooling load between 70 80ºF (21-26ºC).
to call for cooling.
AMBº =_________
LIQº = __________
LIQº_____ - AMBº _____ = APPº_____
sticker located on unit access panel or copy
located at the end of this manual. See table 2 for
to determine applicable charging information for
specific model.
19.
pressures provided on applicable charging
sticker as reference in table 1.
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 4):
SATº = ______
SATº_____ - LIQº _____ = SCº _____
located on unit access panel or copy located at
the end of this manual. See table 3 for to
determine applicable charging information for
specific model.