Bryant 180CNV024, Installation Instructions Manual

Page: 7 / 16

7
CAUTION
!
ENVIRONMENTAL HAZARD
Failure to follow this caution may result in environmental
damage.
Federal regulations require that you do not vent
refrigerant to the atmosphere. Recover during system
repair or final unit disposal.
Follow these steps to properly start up the system:
1. After system is evacuated, close the disconnects to energize
the ID and OD units to assess the user interface (UI), Keep
system in off mode . Under the Advanced function menu,
assess the REQUIRED CHARGE CALCULATION screen.
Enter the lineset length and vapor tube diameter. The wall
control will now display the required charge adjustment
(see Fig. 7) for the lineset and an adjustment for a large in-
door coil if recognized as such by the wall control.
2. Add or remove the required charge adjustment for lineset
length to liquid service valve.
Note:
If lineset is less than 15 feet (--9.4
_
C), charge re-
moval may be necessary.
3. Fully open liquid and vapor service valves.
A170295
Fig. 7 -- Required Charge Adjustment
Calculated in wall control
4. Set wall control to operate cooling in CHARGING mode
(see Fig.7). Charging mode operates system compressor
speed and fan speeds to proper conditions to check the re-
frigerant charge.
NOTE : Do not check charge in a mode other than CHARGING.
5. Select service valve subcool.
6. Wait for the specified stabilization time, depending on line-
set length. Then Compare measured subcooling at liquid
line service valve to target service valve subcool as shown
on CHARGING screens (see Fig. 8).
A170296
Fig. 8 -- Liquid Line Subcooling Target
Step 11 — System Functions And Sequence Of
Operation
The 180CNV models utilize an Evolution communicating wall
control. With a call for cooling, the outdoor fan and compressor are
energized to run at lowest cooling demand. If this does not satisfy
cooling demand, the system will ramp up in stages until it satisfies
the demand. After coping with the higher demand, the unit returns
to lower capacity operation until the demand is satisfied or until an
increase in demand.
When all demand is satisfied, the compressor will shut off. As the
unit operates at lower capacity, system vapor (suction) pressure will
be higher than it is during a standard single--stage system operation
or during a higher capacity operation.
When the outdoor ambient is more the 100
_
F (37.8
_
C), the
outdoor fan will continue to run for one minute after compressor
shuts off. This reduces pressure differential for easier starting in
the next cycle.
The conventional thermostat input is designed to work for
emergency operation only. Connections are Y, and C. The system
will only operate at maximum capacity.
The wall control displays the operation mode and fault codes as
specified in the troubleshooting section. See Table 7 for codes and
definitions.
NOTE: Only one code will be displayed on the outdoor unit
control board (the most recent, with the highest priority). The
latest codes are stored and can be access via the wall control.
Crankcase Heater Operation
This unit has an internal crankcase heater that will be energized
during the off cycle and is intelligently demanded by the system to
prevent the compressor from being the coldest part of the system
thus enhancing the reliability. The crankcase heater will function
as needed any time the outdoor unit is powered. The indoor unit
and UI do not need to be installed for the crankcase heater to
operate properly.
NOTE : Contactor may close intermittently without the unit
starting. This is done to determine whether the control needs to
energize the crankcase heater. Closing the contactor powers the
inverter and allows the system to check compressor temperature.