24VNA6: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
9
5. If the outdoor ambient temperature is between 65°F and 105°F and
the  indoor  temperature  is  between  65°F  and  80°F  then  select
"subcool" (See Fig. 13).
6. The  next  screen  will  show  the  target  subcooling  that  should  be
attained  while  charging  (see  Fig. 14).    Before  selecting  "Start"
verify that the service valves are open. 
7. Upon  selecting  "Start"  the  system  will  enter  into  charging  mode.
The outdoor compressor and fan will operate at a fixed speed and
the  UI  will  display  a  stabilization  time  (see  Fig. 15).    Once  this
clock  reaches  zero  the  charge  can  be  adjusted  to  meet  the  target
subcooling.
8. Compare  the  subcooling  taken  at  the  liquid  service  valve  to  the
subcooling target listed on the charging screen.  Add refrigerant if
the  subcooling  is  low  and  remove  charge  if  subcooling  is  high.
Tolerance should be +0 and -2°F.  
9. If any adjustment is necessary, add or remove the charge slowly (no
greater than 0.5 lb per minute) and allow system to operate for 15
minutes to stabilize before declaring a properly charged system. 
The use of a commercial charge metering device (restrictor) such as
Imperial  liquid  low  side  charger  model  535-C  or  Watsco
ChargeFaster  model  CH200  is  recommended  when  adding
refrigerant to an operating system.  This prevents potential damage
of liquid slugging of the compressor and allows the subcooling to
stabilize quicker.
10. If  the  outdoor  ambient  is  below  65°F  or  above  105°F  then  the
refrigerant must be weighed in.  Press the "weigh-in" option in the
"refrigerant charge" screen (see Fig. 16).  
11. Press the text "line set" and "vapor line" to  choose line set length
and vapor line diameter (see Fig. 17 and Fig. 18). After complete,
press "next" to advance to next screen.  
12. If this is a new install, i.e. the ODU is factory charged, then select
"new install" in the "charging mode selection" screen (see Fig. 19)
.
13. The "new install charge weigh-in" screen will show the additional
charge that needs to be added to the system to account for the ID
coil and line set (see Fig. 20).
14. If this is a complete re-charge then select "complete recharge" in the
"charging mode selection" screen.  This screen will show the total
amount of charge to add for the indoor coil, line set, and outdoor
unit  (see  Fig. 21).    The  "charge  breakdown"  screen  shows  the
charge required for each component of the system.
15. Add additional required charge for line set and indoor coil size then
fully open liquid and vapor service valves. 
Charge  level should then be appropriate for the system to achieve
rated capacity. The charge level could then be checked at another
time when both the indoor and outdoor temperatures are in a more
favorable range.  This ensures maximum efficiency and reliability. 
If lineset is less than 15 feet (4.57 m) in length, charge removal may
be necessary and will be shown as a negative number on UI screen.
UI screen displays charge in lb and oz, while unit rating plate is in
decimal format.
A200031
Fig. 13 – Select Refrigerant Subcooling
A200032
Fig. 14 – Liquid Service Valve Subcooling Target
A200033
Fig. 15 – Charging Mode Information Screen
A200034
Fig. 16 – Weigh-in Option for charging below 65°F OAT and above 
105°F OAT
CAUTION
!
UNIT OPERATION HAZARD
Failure to follow this caution may result in improper unit operation.
For  new  installations  only: Add  additional  refrigerant  due to  indoor
coil, line set and vapor line settings. Outdoor unit is pre-charged with
weight of refrigerant shown on rating plate.