Lennox EL16XC1 Series Installation And Service Procedure page 30

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)
APPROACH TXV
B
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
C
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.
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 and
BELOW
Figure 18. Using HFC-410A Approach (TXV) Charge Method
ABOVE or
BELOW
64ºF and
BELOW
CARDBOARD OR
PLASTIC SHEETS
Figure 19. Using HFC-410A Subcooling (TXV) Charge Method
1. Connect gauge set as illustrated in figure 14.
65ºF
2. Confirm proper airflow across coil using figure 15.
and
3. Compare unit pressures with charging sticker, Normal
ABOVE
Operating Pressures.
4. Set thermostat to call for heat (must have a cooling
load between 70‐80ºF (21-26ºC).
5. When heat demand is satisfied, set thermostat to call
for cooling.
6. Allow temperatures and pressures to stabilize.
7. Record outdoor ambient temperature:
AMBº =_________
8. Record liquid line temperature:
LIQº = __________
9. Subtract to determine approach (APPº):
LIQº_____ - AMBº _____ = APPº_____
10. Compare results with charging sticker on unit or at the
end of this manual.
1. Connect gauge set as illustrated in figure 14.
65ºF
2. Confirm proper airflow across coil using figure 15.
and
3. Compare unit pressures with charging sticker,
Normal Operating Pressures.
ABOVE
4. Set thermostat to call for heat (must have a cooling
load between 70‐80ºF (21-26ºC)
5. Measure outdoor ambient temperature
6. When heat demand is satisfied, set thermostat to call
for cooling
7. Allow temperatures and pressures to stabilize.
NOTE - If necessary, block outdoor coil to maintain
325 - 375 psig.
8. Record liquid line temperature:
LIQº = ______
9. Measure liquid line pressure and use the value to
determine saturation temperature (see table 3):
SATº = ______
10. Subtract to determine subcooling (SCº):
SATº_____ - LIQº _____ = SCº _____
11. Compare results with applicable charging sticker
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.
Page 30