Amana VCA Service Instructions Manual page 32

SERVICING
openings within a single heating or cooling cycle, all func-
tions will be locked out. Lockout is reset by cycling off the
thermostat or by removing 24 VAC power to the board.
The Ranco board requires interrupt of 24 VAC to the
board to reset.
11164401 LED Diagnostic Display
LED 1 LED 2
ON ON CONTINOUS
OFF OFF CONTINOUS
ON OFF CONTINOUS
OFF ON CONTINOUS
ALTERNATING
ON/OFF ON/OFF
FLASHES
FLASHING
ON/OFF ON/OFF
TOGETHER
30
60
90 DEFROST
The operation of the integrated defrost control used on the
RHA-B-A & RHE--A2B models is very similar to that of the
solid state control used in the RHA--A2A models. The time
interval is determined by the position of the time select
jumper which is factory set to the specific unit design. The
control will default to 90 minutes if the jumper is missing or
if the jumper is left in the test position for more than 5
minutes. The 20214302 control is physically smaller than
the 11164401 control and does not include the LED diagnos-
tic display.
32 Rev 1
- After 3 pressure switch
FAULT
Board Malfunction
Board Malfunction
or No Power
Pressure Switch
3 Time Lockout
Pressure Switch Open
Anti Short Cycle Lockout
Normal Operation /
Power to Board
FAN
CC
HI-P
LO-P
RV
BOARD
DFS
W C R O Y
The board counts the compressor run time in the heating
mode after the 30/60 control closes. If the 30/60 control
opens, the timer will reset. The board will terminate defrost
when the 30/60 control opens or after 14 minutes compres-
sor run time which ever occurs first. If the thermostat is
satisfied during the defrost cycle, timing is suspended, the
board does not reset.
During the defrost mode, the fan relay on the control board
opens contacts which stop the fan motor. The reversing
valve solenoid is energized to place the unit in the cooling
mode. Also W2 is energized for signaling electric heat
operation.
The defrost mode will be temporarily suspended if the
thermostat cycles off, or a pressure switch opens. Upon
closure of pressure switches or resumption of thermostat
demand, defrost activity will resume, as soon as the 5
minute short cycle time is satisfied.
- Placing the jumper in the test position will
accelerate the timing by a factor of 128. With the 30/60
control closed a 90 minute defrost interval will time out in
approximately 42 seconds, a 14 minute defrost will time out
in approximately 7 seconds. If the jumper is in the test
position at power up of the board, the jumper will be ignored.
To reenter the test mode briefly remove the jumper and
replace in test mode.
Some additional features that are built into this control
are:
includes short cycle protection. A five minute lockout will
occur when the 24 VAC power to the contactor is removed
by the thermostat demand cycling off or by the opening of a
pressure switch.
opens, the contactor is locked out for five minutes. After 5
minutes, if the pressure switch is closed, normal operation
will resume. The 20214302 control will ignore the low
pressure control in the defrost mode to avoid nuisance
tripping of the low pressure switches in this phase of the
defrost function.
Adaptive Defrost Control-RHD/RHE Models
The adaptive defrost board works in much the same way as
the standard solid state timer except that it is not set to a
fixed time between defrosts. Defrosts may be a minimum of
30 minutes apart, to a maximum of 180 or 360 minutes apart
based on ambient conditions.
The optimum defrost time is programmed into the defrost
control (5.5 or 7 minutes). If the defrost takes less than the
optimum defrost time, the defrost board will increase the
time before the next defrost. If the next defrost also is less
than the optimum defrost time, the board will again increase
the time before the next defrost.
As conditions change increasing the frost build up on the
coil, the length of defrost will also increase above the
optimum defrost time, causing the defrost cycles to come
more frequently.
- The integrated defrost control
- When a pressure switch