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22 - Solid State Starter/CM-2 MUX output Channel 7
23 - Refrigerant Level Position
24 - Proximity Probe High Speed DrainTemperature
(except "P" Compressors)
(Not applicable to chillers equipped with Program ver sion
C.MLM.01.03 or higher)
25 - Not Used
26 - Not Used
27 - Remote Leaving Chilled Liquid Temperature
Setpoint (0-20mA or 4-20mA)
28 - Remote Current Limit Setpoint (0-20mA or
4-20mA)
29 - Condenser Flow Sensor (style F and later chillers)
(Flash Memory Card version C.MLM.01.07.xxx and
later).
30 - Evaporator Flow Sensor (style F and later chillers)
(Flash Memory Card version C.MLM.01.07.xxx and
later)
Procedure:
1. From the chart above, select the analog input that
is malfunctioning. All inputs except channel 0, 15
through 22, 27 and 28 are sensors that connect di-
rect ly to the Microboard via shielded cable. Chan nel
0 is a ref er ence voltage for the Analog circuits on
the Microboard. Channels 15 through 22 are mul-
tiplexed outputs from the Solid State Starter (Solid
Sate Starter applications) or CM-2 Current Module
(Electro-Mechanical Starter applications). Chan nels
27 and 28 are Remote Setpoint inputs used in Analog
Remote mode.
2. Refer to Wiring Diagrams listed in front of this Sec tion
to identify the device that performs this func tion and
the jack and pin connection to the Microboard.
3. • Channel 0:
Using a Voltmeter, measure the voltage be tween
Microboard TP6 (+2.5VDC) and TP1 (Gnd).
Compare this measured value to the displayed
val ue. If the value is not within +10%, replace the
Microboard.
• All channels except 0, 1, 15-22:
Using a Voltmeter, measure the analog input to the
Microboard. Make the measurement between the
device output and Ground connection to the de vice.
For example, measure the output of the Evap o ra tor
Transducer at Microboard J8-18 (sig nal) to J8-9
(Gnd).
• Channels 15-22:
YORK INTERNATIONAL
Select the desired channel by pressing the SE LECT
CHANNEL key and using the
place the arrow head next to the de sired chan nel.
Then, freeze the address of that channel to the Solid
State Starter or CM-2 MUX. Then mea sure MUX
output at Microboard J10-6 (signal) to J10-5 (Gnd).
When com plet ed, press CANCEL FREEZE key.
• Channels 27, 28:
IMPORTANT! This procedure only applies to
4-20mA in puts. It does not apply to 0-10VDC in-
puts. Using a Voltmeter, measure the Remote Cur-
rent Limit setpoint input at J22-2 (signal) or Re mote
Leaving Chilled Liquid Temperature setpoint input
at J22-4 (signal) to J22-5 (Gnd).
4. Compare the measured value in the previous step
with the value displayed on the Analog Inputs
Screen for that value.
5. If the measured value is not within +15% of the dis-
played value, replace the Microboard. Oth er wise,
proceed to the troubleshooting procedure below to
fi nd the cause of the problem.
6. When all desired tests have been performed, press
DIAGNOSTICS key to return the MAIN DI AG -
NOS TICS Screen.
Troubleshooting :
• All Channels except 0, 1, 15-22, 27, 28:
1. Disconnect both ends of the cable of the An a log
in put that is malfunctioning. Using an Ohm me ter,
per form a continuity test on all conductors in the
cable. An open circuit would indicate the cable is
defective.
2. Using a Voltmeter, measure the +12VDC supply
volt age input at the Microboard J1-3 (+12VDC) to
J1-2 (Gnd). If voltage is < 11.5VDC, check wir ing
to Power Supply. If wiring is OK, the Pow er sup ply
is most like ly defective.
3. Using a Voltmeter, measure the supply voltage
(+5VDC, +1 2VDC or +24VDC) to the sensor. If
volt age is not within +10% of specifi ed voltage,
dis connect J7, J8 and J9 from the Microboard.
This disconnects all analog devices from the
Microboard. If the voltage increases to the cor-
rect level, a Ther mistor or Trans duc er is shorted.
Lo cate the short ed device and re place. If, after
dis connecting the con nec tors the supply volt age
is still not with in 10% of the specifi ed value, the
voltage supply source (Microboard or Power Sup-
ply) is most like ly de fec tive.
FORM 160.54-M1(503)
and
keys to
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24
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