HPS Rotary Screw Compressor Units
070.700-IOM (MAR 21)
Page 38
Maintenance
Temperature sensor
Troubleshooting
Confirm the setup of the channel on the calibration or
analog board #1 setup screen. If the temperature probe
reading bottom end is -459°F (272.8°C) or top end is
+463°F (239.4°C), see the following troubleshooting.
Are you read-
ing the bottom
end?
The probe or wires to the probe
are open or the probe is shorted to
ground pulling down the power/exci
-
tation.
Check the power at the analog board
between the + and – of the channel
for that probe. For example, discharge
temperature would be Channel 2 on
the P4A terminal strip of the analog
board.
Is there a sig
-
nal of 12 VDC
to 15 VDC?
If yes, the probe is not shorted to
ground but is most likely open.
Do continuity tests to determine if it is
the wiring or the sensor that is open.
Correct as necessary.
Are you read-
ing the top
end?
The sensor is being shunted and full
signal is coming back to the board.
Check the wiring by unplugging the
connector at the sensor, disconnecting
from the analog board, and doing a
continuity test across the wires re-
moved from the board. If this is open,
the shunt is in the sensor. It is always
a good idea to physically inspect the
wiring of the DIN Plug.
Figure 39: Temperature transmitter
Warning
Be extremely careful not to loosen thermowell while
attempting to remove the temperature sensor.
The use of two wrenches is necessary to ensure the
thermowell remains stationary. Loss of oil and/or re-
frigerant could occur. Exposure to refrigerant fumes
and/or hot oil can cause injury or death.
Replacement
1. Shut off control power.
2. Remove
DIN connector plug from transmitter.
3.
Unscrew knurled ring and remove
transmitter unit.
4. Apply thermal compound to new sensor assembly,
insert into
thermal well, and tighten knurled ring.
5.
Apply DIN connector plug to transmitter.
6. Turn on control power.
Notice
The temperature sensor is factory set. If calibration
is required, refer to
Calibration Instructions
in pub-
lication
090.040-O, Quantum HD Control Panel
for
service technicians.
Oil level switch
Caution
This device is static sensitive. Follow the correct ESD
procedures when handling.
Troubleshooting
Question
Probable cause and
correction
Are the red or
green indicator
lights illuminated
on the switch?
If yes, check that 2CR or OLCR is
energized and that module 13 of
digital board #1 is energized as
well as the status of module 13 is
ON at the service screen for digi
-
tal board #1. Correct as necessary.
If the red or green
indicator lights are
not illuminated on
the switch, is there
oil present in the
lower sight glass
of the separator?
If not, add oil to the separator.
If yes, confirm that a 24 VDC sig
-
nal is being sent to the sensor for
correct operation.
Is a 24 VDC signal
being sent to the
sensor for correct
operation?
If yes, replace the oil level sensor.
If not, check the fuse of wire
1001.
If blown, check for shorts of wire
1001 and correct and replace the
fuse.
If the fuse is good, check for 24
VDC immediately upstream of the
fuse back to the power supply.
Correct as necessary.
Are there red
flashing lights?
This indicates power but no con-
tact between the electronic head
and the sensor well.
Are there green
flashing lights?
This indicates power but no con-
tact between the electronic head
and the sensor well.
Are there solid red
lights?
This indicates the presence of oil.
