Check Charge - Carrier Infinity 25VNA8 Service Manual

CHECK CHARGE

Charge in CHARGING mode (communicating only)
Unit is factory charged for 15ft (4.57 m) of lineset. If any
refrigerant charge adjustment is required due to the user inputted
line set length, the UI will calculate and display the target
subcooling and the amount of additional charge to be added.
Therefore, the UI is your source of information for charging the
system correctly. Refrigerant charge adjustment amount for adding
or removing 0.6 oz/ft (17.74 g/m) of 3/8 liquid line above or below
15ft (4.57 m) respectively. Perform a final charge check only when
in cooling and OD is between 65_F (18_C) and 100_F (38_C).
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.
Charging using the subcooling method optimizes charge volume
and is preferred if possible. If the outdoor temperature is between
65_F - - 100_F (18.3_C - - 37.8_C) and indoor temperature is 70_F
- - 80_F (21.1_C - - 26.7_C), the option to further adjust charge
using "service valve subcool" will be available in the "charging
mode selection" screen. If temperatures are outside of range, this
option will be greyed out and not selectable. Inaccurate charging
may result in nuisance fault codes.
Initial start- -up can be performed using calculated charge only and
once conditions are within range, the "Service Valve Subcool"
option will become selectable.
Once start is selected the system will operate in a preset mode until
"done" is selected. Wait for required stabilization time then check
subcooling at service valve.
Adjust charge as required to meet target service valve subcooling
shown on screen - -3/+0 degree. If any adjustment is necessary, add
or remove the charge slowly (no greater than .5 lb per minute) and
allow system to operate for 25 minutes to stabilize, before
declaring a properly charged system.
Fig. 9 – Adjusting Charge Using Service Valve Subcool
Fig. 10 – Service Valve Subcool Target Value
Charging Non- - Communicating Systems
Charging Procedure:
cooling by creating a large differential between room temperature
and set point on thermostat. Use multi- -meter to verify that 24
VAC is present between C, Y1 /Y2 terminals at outdoor unit.
Factory charge amount is shown on unit rating plate for high stage.
Target subcooling chart is provided on back of control box door
see Fig. 12 - - 26 for example. To properly check or adjust charge,
condition must be favorable for subcooling charging. Favorable
conditions exists when outdoor temperature is between 65_F
(18_C) and 100_F (38_C), and the indoor temperature is between
70_F (21_C) and 80_F (27_C). Follow the procedure below:
Unit is factory charged for 15ft (4.57 m) of lineset. Adjust charge
by adding or removing 0.6 oz/ft (17.7 g/m) of 3/8 liquid line above
or below 15ft (4.57 m) respectively.
For standard refrigerant line lengths (80ft/24.4 m or less), allow
system to operate in cooling mode at least 25 minutes. If conditions
are favorable, check system charge by subcooling method. If any
adjustment is necessary, adjust charge slowly and allow system to
operate for 25 minutes to stabilize before declaring a properly
charged system.
If the indoor temperature is below 70°F (21.11°C), or the outdoor
temperature is not in the favorable range, adjust charge for line set
length above or below 15ft (4.57 m) and indoor fan coil /furnace
coil per Table 1 and 2. Charge level should then be appropriate for
the system to achieve rated capacity. The charge level should then
be checked at another time when the both indoor and outdoor
temperatures are in a more favorable range.
NOTE: If the line length is beyond 80ft (24.38 m) or greater than
20ft (6.10 m) vertical separation see Long line guideline for special
charging requirement.
A14573
A14574
9
Fig. 11 – Stabilization Time
Force system to operate in high stage
A14575