10
The outdoor fan output (ODF) will remain off for 20 seconds after
termination. This delay will allow time for the system to capture
the heat from the outdoor coil and reduce the “steam cloud” effect
that may occur on transition from defrost to the heating cycle. The
outdoor fan output OFF delay of 20 seconds may be defeated to
enable the fan to energize immediately at the time of termination
and 12 seconds prior to the reversing valve de--energizing, through
the User Interface setup screen available with SYSTXBBUID01--C
UI, or forced defrost pins as follows:
S
The ODF fan delay defeat can be toggled by shorting the
forced defrost pins for >15 seconds while in the standby
mode (status LED on solid). The LED will start to flash when
the toggle has taken place.
S
Status code 4 shows the fan delay defeat is active (no delay)
S
Status code 3 shows that it is not active (20 second delay)
The code will continue to be displayed until after the short is
removed. Once the short is removed, there is a 5 second wait
before the code is cancelled. The code that is flashing will finish
before going back to sold LED. the control is shipped with the
ODF fan delay defeat NOT active.
the change in status is
remembered until toggled to a new status. A power down / power
up sequence will not reset the status. It may be necessary to do the
toggle twice to cycle to the desired state of defeat.
Defrost Hold
In a non--communicating system, if the thermostat becomes
satisfied (Y1 or Y1 and Y2) before the defrost cycle is terminated,
the control will “hold” in defrost mode and finish the defrost cycle
on the next call for heat.
On 286A and 288A models, with communicating Evolution
Control, defrost hold is not needed in a communicating system
because the User Interface will complete the defrost cycle before
shutting down the system.
Forced Defrost
With non--communicating (non--Evolution) control, forced defrost
can be initiated by manually shorting the 2--pin header labeled
FORCED DEFROST (see Fig 6) on the control board for 5
seconds then releasing.
On 286A and 288A with communicating (Evolution) control,
forced defrost is initiated with the User Interface.
On all models, during a Forced Defrost:
S
If coil temperature is at defrost temperature of 32
_
F (0
_
C),
and outdoor air temperature is below 50
_
F (10
_
C), a full
defrost sequence will occur.
S
If coil temperature or outdoor air temperature does not meet
the above requirements, an abbreviated 30 second defrost will
occur.
Quiet Shift
Quiet Shift is a field--selectable defrost mode which may eliminate
occasional noise that could be heard at the start of the defrost cycle
and restarting of the heating cycle. With a non--communicating
system, this feature must be enabled by selecting the 3rd position
of the 3--position dip switch. For 286A and 288A models with
communicating (Evolution) systems, it must be enabled at the User
Interface. When activated, the following sequence of operation
will occur. Reversing valve will energize and compressor will turn
off for 30 seconds, then turn back on to complete defrost. At the
end of the defrost cycle, the reversing valve de--energizes,
compressor will turn off for another 30 seconds, and the fan will
turn off for 40 seconds, before starting in the heating mode.
Liquid--Line Solenoid Accessory
In heat pump long--line applications, a liquid--line solenoid is
required to control refrigerant migration in the heating mode. The
solenoid should be installed near the outdoor unit with the arrow
facing the outdoor unit. This is the direction of flow control. See
application manual for long--line application details.
Accessory Liquid Solenoid with Evolution Communicating
Control:
When using the Evolution Control, the liquid--line
solenoid output is provided at the Y1 connection. Connect the
solenoid as shown in the wiring label diagram. This is a 24vac
output that is energized whenever the compressor is energized. It
closes, in the compressor off mode, to prevent refrigerant migration
into the unit through the liquid--line.
On Models with Accessory Liquid Solenoid Using a
Non--Communicating Thermostat:
The liquid solenoid is
connect to the Y1 and C terminal connections. The liquid solenoid
closes, in the compressor off mode, to prevent refrigerant migration
into the unit through the liquid--line.
Check Charge
All 286A units must be charged in high stage only.
Factory charge amount and desired subcooling are shown on unit
rating plate. Charging method is shown on information plate inside
unit. To properly check or adjust charge, conditions must be
favorable for subcooling charging. Favorable conditions exist
when the outdoor temperature is between 70
_
F and 100
_
F
(21.11
_
C and 37.78
_
C), and the indoor temperature is between
70
_
F and 80
_
F (21.11
_
C and 26.67
_
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 of 3/8 liquid line above or below
15ft (4.57 m) respectively.
For standard refrigerant line lengths (80 ft/24.38 m or less), allow
system to operate in cooling mode at least 15 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 15 minutes to stabilize before declaring a properly
charged system.
If the indoor temperature is above 80
_
F (26.67
_
C), and the
outdoor temperature is in the favorable range, adjust system charge
by weight based on line length and allow the indoor temperature to
drop to 80
_
F (26.67
_
C) before attempting to check system charge
by subcooling method as described above.
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) only. Charge level should then
be appropriate for the system to achieve rated capacity. The charge
level could then be checked at another time when the both indoor
and outdoor temperatures are in a more favorable range.
NOTE
: If line length is beyond 80 ft (24.38 m) or greater than 20
ft (6.10 m) vertical separation, See Long Line Guideline for
special charging requirements.
Heating Check Chart Procedure
To check system operation during heating cycle, refer to the Heat
Pump Charging Instructions label on outdoor unit. This chart
indicates whether a correct relationship exists between system
operating pressure and air temperature entering indoor and outdoor
units. If pressure and temperature do not match on chart, system
refrigerant charge may not be correct. Do not use chart to adjust
refrigerant charge.
NOTE
: In heating mode, check refrigerant charge only when
pressures are stable. If in doubt, remove charge and weigh in
correct refrigerant charge.
NOTE
: When charging is necessary during heating season, charge
must be weighed in accordance with unit rating plate,
±
0.6 oz./ft.
of 3/8--in. liquid--line above or below 15 ft., respectively.
EXAMPLE
:
To calculate additional charge required for a 25--ft. line set:
25 ft. -- 15 ft. = 10 ft. X 0.6 oz./ft. = 6 oz. of additional charge.
286A
/288A
