it is completely out of range it shuts the unit down on temperature failure. While
investigating, remember to open the electrical disconnect and lock and tag.
The next step is to press the display-select button twice and check the value of
the shutdown temperature.
If the temperature range is acceptable, check the resistance of the temperature
sensor. Do this by disconnecting the cable wires from terminals 20 and 21.
Attach an OHM meter to the leads of the thermister.
Remember the temperature must be held constant on the sensor in order to
measure a constant OHM value. The use of a therometer may be an advantage.
Use the following chart as a guide and match the OHM value to a sensor
temperature. This will verify if the temperature sensor is good or bad.
The next step is to check the continuity of the interface boards. Remember to
remove all electrical power, lock and tag. Remove the 5 volt DC ribbon cable
and check for continuity between terminal 20 and the top left most pin, and
continuity between 21 and the top right most pin. Check continuity of pin 22 to
ground, terminal 27. Also, check continuity of 22 to either of the bottom most
pins which are ground connections. If all continuity checks are good, replace
the Intellisys controller.
Remember, intermittent contact associated with the interface board may be
detected with slight flexing or elevated room ambient conditions.
Degree F° OHMS
50 20244
60 15475
70 11934
80 9282
90 7277
100 5748
110 4573
120 3663
130 2955
140 2400
150 1962
160 1614
170 1335
180 1110
190 928
200 780
210 658
220 558
230 476
240 407
MESSAGE -06- PRESSURE SENSOR FAILURE
When the-06-fault exists the Intellisys determines pressure sensor failure by
taking the reading of the sensor and checking it against some logical range. If
it is out of range, it considers the sensor to be failed.
-9-
-10-
Press display select to obtain a discharge air pressure reading in the display
window. This is the shutdown pressure.
The controller can be set for 100-125-150 or 175 psig. The controller will shut
down if the discharge pressure exceeds 15 psig over any of the preset discharge
pressures programmed into the controller by the factory.
SYMPTOMS
1. The Intellisys controller does not power up, even though power is present
at the primary and secondary contacts of the transformer and interface
board or intermittent contact will give various error codes.
The cause of this is the electrical signal in the pressure transducer and can
ground itself fully or intermittently when the 4 prong adapter is installed in the
cable housing.
The spade connection at the end of the wire may contact the inner metal wire
sheath of the cable connector.
There are four wires inside the cable (red, green, black and white). Therefore,
several combinations of ground contact are possible.
TO CORRECT THE PROBLEM:
1. Loosen the nut, pull slightly on cable.
If you have a unit that is showing symptoms as described, it may be necessary
to repair or replace the existing cable.
This problem has been corrected on new units with the addition of a heat shrink
shield at the end of the transducer cable to prevent contact.
Re-assemble the connector and plug it back in.
The pressure transducer should be calibrated at start up and anytime a
component associated with the transducer or Intellisys system is replaced.
Calibration of the transducer is accomplished as follows:
1. All pressure must be removed from the pressure transducer. Be sure to
remove the tubing attached to the line sump solenoid valve.
2. The controller must be in the ready to start mode. (“O” in the display
window).
3. Press the step up/down arrows at the same time, (ONCE). When the
arrows are pressed, the green LED light on the display-select will shift to
SUMP and then return to discharge air pressure.
4. This procedure can be done anytime you suspect an error in the pressure
transducer circuit.
IT IS VERY IMPORTANT TO HAVE THE AIR PRESSURE REMOVED FROM
THE TRANSDUCER PRIOR TO CALIBRATION.
MESSAGE -05- TEMPERATURE SENSOR FAILURE
If this fault shows-05-temperature sensor failure, the Intellisys looks at the value
from the temperature sensor and checks to see if it is within a proper range. If
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