15
S
TEP
5. A
DJUST
R
EFRIGERANT
LEVEL
Using service equipment, add or recover refrigerant according to
the calculation in Step 1. Allow system to stabilize for 10 minutes
after adjusting charge level.
S
TEP
6. M
EASURE
S
UBCOOLING
TO
V
ERIFY
P
ROPER
C
HARGE
NOTE:
Charging equipment must use dedicated PVE oil gauges
and hoses.
1. Purge gauge lines.
2. Connect service gauge manifold to base valve service ports.
3. Convert the liquid pressure to temperature using a
temperature/pressure chart.
4. Temporarily install a thermometer on the liquid line at
the liquid line service valve.
a. Ensure the thermometer makes adequate contact
and is insulated for best possible readings.
5. Subtract the liquid line temperature from the converted
liquid pressure to determine subcooling.
6. Before starting the Subcooling adjustment, make sure the
outdoor ambient temperature is in a below range and the
unit is operating at 100% capacity.
SUBCOOLING = (SAT. LIQUID TEMP.) - (LIQUID LINE
TEMP.)
SUPERHEAT = (SUCT. LINE TEMP.) - (SAT. SUCT. TEMP.)
OD Ambient Temp
(degF)
< 65 °F
65°F to 105°F
> 105 °F
Subcooling
(degF)
Weigh in
Charge
7°F to 9°F
Weigh in
Charge
Note: Subcooling information is valid only while the unit is operating
at 100% capacity or 100% of compressor speed in CHARGE MODE.
Compressor speed is displayed under STATUS menu in the thermostat.
Charging Table
7. The system subcooling should be 7 to 9°F. If not in that
range, adjust subcooling and superheat according to the
following procedure.
a. If subcooling and superheat are low, adjust TXV to 7 to
9°F superheat, then check subcooling.
NOTE:
To adjust superheat, turn the valve stem clockwise
to increase and counter clockwise to decrease.
b. If subcooling is low and superheat is 7 to 9°F, add charge
to rise subcooling to 7 to 9°F, then check superheat.
c. If subcooling is low and superheat is high, add charge to
rise subcooling to 7 to 9°F, then check superheat.
d. If subcooling is 7 to 9°F and superheat is high, adjust
the TXV valve to 7 to 9°F superheat, then check
subcooling.
e. If subcooling and superheat are high, adjust the TXV
valve to 7 to 9°F superheat, then check subcooling.
f. If subcooling is high and superheat is 7 to 9°F, remove
charge to lower the subcooling to 7 to 9°F, then check
superheat.
g. If subcooling is high and superheat is low, adjust the
TXV valve to 7 to 9°F superheat and remove charge to
low the subcooling to 7 to 9°F.
h. If subcooling is 7 to 9°F and superheat is low, adjust the
TXV valve to 7 to 9°F superheat and remove charge to
lower the subcooling 7 to 9°F, then check the superheat.
NOTE:
Not more than 0.5 lb. (8 Oz.) of refrigerant must
be added to the system in order to achieve the target
subcooling. It is recommended to add 4 oz. refrigerant
each time and try adjusting the TXV and let the system
stabilize.
C
HECK
THE
S
CHRADER
PORTS
FOR
LEAKS
AND
TIGHTEN
VALVE
CORES
,
IF
NECESSARY
. I
NSTALL
CAPS
FINGER
-
TIGHT
.
NOTICE
D
O
NOT
ADJUST
THE
CHARGE
BASED
ON
SUCTION
PRESSURE
UNLESS
THERE
IS
A
GROSS
UNDERCHARGE
.
NOTICE
Rain
Shield
I
F
THE
RAIN
SHIELD
WAS
REMOVED
DURING
THE
INSTALLATION
PROCESS
,
BE
SURE
TO
RE
-
INSTALL
IT
AFTER
CHARGING
THE
UNIT
.
NOTICE
H
EAT
P
UMP
WITH
O
UTDOOR
T
EMPERATURE
L
OCKOUTS
It is recommended to set the outdoor temperature lockouts
during the initial thermostat set up. This will enable the com-
pressor to be turned off and switch heating source from refrig-
eration to auxiliary/secondary heating under low ambient con-
ditions.
