108
YORK INTERNATIONAL
perature, as sensed by thermistor RT7, has increased
to 260°F (126.7°C). It will be allowed to restart when
temperature decreases to 259°F (126.1°C). To restart
unit, press UNIT switch to STOP/RESET position, then
to START position.
(EPROM version A.02F.01 or later)
The unit has shutdown because the hot water supply
temperature, as sensed by thermistor RT7, has in-
creased to the shutdown threshold. The actual shutdown
threshold is determined by the position of Micro Board
program jumper JP5. The unit design determines the
appropriate position of this jumper: Standard tempera-
ture units require the jumper to be in, high temperature
units (equipped with additional tube supports) require
the jumper be removed. This jumper must never be
changed by anyone but a qualified service technician.
The unit can be restarted when the temperature de-
creases to the reset threshold. To restart the unit, press
UNIT switch to STOP/RESET position, then to START
position. The thresholds are as follows:
JP5 – IN – Standard units,
Shutdown threshold = 255.0°F (123.9°C)
Reset threshold
= 254.0°F (123.3°C)
OUT – High temperature units,
Shutdown threshold = 270.0°F (132.2°C)
Reset threshold
= 269.0°F (131.7°C)
SUN 12:00 AM MOTOR COOLANT LEVEL FLOAT SW
(Applicable only to units equipped with Franklin pumps;
Micro Board program jumper JP2 OUT)
The unit has shut down because the refrigerant and so-
lution* pumps motor coolant level float switch (2F) has
opened indicating a low coolant level. The unit can be
restarted when the float switch has closed. To restart
unit, press the UNIT switch to STOP/RESET position,
then to START position.
*On 50 Hz Models YIA-10E3 – YIA-14F3, the solution
pump is replaced by two pumps; an absorber pump and
a generator pump.
SUN 12:00 AM REFRIGERANT PUMP FLOAT SW FAILURE
(EPROM version A.02F.02 or later; applicable only to
units equipped with Buffalo pumps, Micro Board program
jumper JP2 IN)
The unit has shut down because the REFRIGERANT
FLOAT SWITCH SHUTDOWN setpoint timer elapsed
before:
a.
the refrigerant pump was started at unit start or,
b.
restarted after the pump was shutdown due to
low refrigerant level.
The “Refrigerant Float Switch Shutdown” timer (20 to 60
minutes) is a setpoint that determines the number of
minutes the unit is permitted to run without the refriger-
ant pump running. The timer is started when the unit
enters SYSTEM RUN and at the instant the refrigerant
pump is shut down due to low refrigerant level. Since
the refrigerant pump is started only after float switches
1F and 3F close, indicating sufficient refrigerant level at
the pump input, and the pump was shutdown for an ex-
cessive amount of time, this shutdown indicates the pos-
sibility that either 1F or 3F has failed to close.
The “Refrigerant Float Switch Shutdown” setpoint timer
can only be programmed by a qualified service techni-
cian using procedure in MicroComputer Control Center
“Service” manual, Form 155.16-M3.
To restart unit, press UNIT switch to STOP/RESET po-
sition, then to START position.
SUN 12:00 AM REF PUMP FLOAT SW CONFLICT
(EPROM version A.02F.02 or later; applicable only to
units equipped with Buffalo pumps, Micro Board program
jumper JP2 IN)
The unit has shut down because float switches 1F and
3F are in conflicting positions. Since float switches 1F
and 3F are used to detect if there is sufficient refrigerant
level at the refrigerant pump input, it is important that a
failed or stuck float switch is detected. Therefore, to as-
sure both float switches are operational, the program
compares the state of 1F to 3F. To illustrate, as the re-
frigerant level rises against the float, it causes the switch
to close. When the level decreases below the float, the
switch opens. Since 1F is at a higher level than 3F, it is
not possible 3F would be open if 1F is closed; unless
one of the switches is stuck in one position.
NOTE: The state of each float switch is not recognized
as being valid until it has been in the same state
for the duration of the respective float switch timer.
1F is determined by REFRIGERANT PUMP
START-UP DELAY setpoint timer. 3F is deter-
mined by REFRIGERANT PUMP SHUTDOWN
DELAY setpoint timer. Therefore, the float switch
conflict will be allowed to exist for the duration of
the respective timer, depending upon which float
switch is causing the conflict.
The unit will be allowed to restart after the float switch
conflict has been resolved. To restart unit, press UNIT
switch to STOP/RESET position, then to START posi-
tion.
