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Defrost
This user interface (UI) offers 5 possible defrost interval times: 30,
60 and 90 minutes, or AUTO. The default is AUTO.
Defrost interval times: 30, 60, and 90 minutes or AUTO are
selected by the Evolution Connex Control User Interface if using
UI. The 90 and 120 minute selection will default to 60 minutes at
ambient below 37 degrees. The 120 minute selection will default
to 90 minutes at ambient above 37 degrees.
If using non- -communicating thermostat, defrost intervals are set
using dip switches on outdoor control board (see Fig. 15). AUTO
defrosts adjusts the defrost interval time based on the last defrost
time as follows:
S When defrost time <5 minutes, the next defrost interval=90
minutes. (outdoor temperature above 37_F)
S When defrost time 5- -7 minutes, the next defrost interval=60
minutes.
S When defrost time >7 minutes, the next defrost interval=30
minutes.
Fig. 15 - - AOC Control Board
The control board accumulates compressor run time. As the
accumulated run time approaches the selected defrost interval time,
the control board monitors the coil temperature sensor for a defrost
demand. If a defrost demand exists, a defrost cycle will be initiated
at the end of the selected time interval. A defrost demand exists
when the coil temperature is at or below 32_F (0_C) for 4 minutes
during the interval. If the coil temperature does not reach 32_F
(0_C) within the interval, the interval timer will be reset and start
over.
S Upon initial power up the first defrost interval is defaulted to 30
minutes. Remaining intervals are at selected times.
S Defrost is only allowed to occur below 50_F (10_C) outdoor
ambient temperature.
The defrost cycle is terminated as described below.
S When OAT is > 25_F (+3.89_C), defrost terminates if outdoor
coil temperature (OCT) > 60_F (+15.6_C). And a minimum of 2
minutes defrost length.
S When OAT
25_F (+3.89_C), defrost will terminate if OCT is
±
>45_F (+4.4_C) and a minimum of 2 minutes defrost length.
S Or 10 minutes has passed.
At the defrost termination, the outdoor fan will turn on 10 seconds
before the reversing valve switching.
NOTE: Compressor speed during defrost will go to defrost speed.
Step 12 — 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 or indoor coil, 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 +0/- -3 degrees for tolerance. 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.
A14021
Fig. 16 - - Adjusting Charge Using Service Valve Subcool
Fig. 17 - - Service Valve Subcool Target Value
11
A14573
A14574
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