Temperature Sensors

All sensors should be properly installed as follows:

• Supply air sensors must be inserted to the bottom of the sensor tube and completely sealed by the grommet connection.

• Return air sensor installs in a grommet between the evaporator fans.

• Evaporator coil (defrost) sensor must be placed in the middle of the coil and 75 mm deep between the fins.

• Ambient sensor must be placed on the bottom plate of the right forklift pocket.

• Compressor discharge pressure transducer is attached to compressor head by adhesive. Refer to (Pressure Transducer (Sensor)).

The controller constantly monitors the left hand and right hand supply sensors, return sensor and defrost (evaporator coil) sensor to determine when to initiate a demand defrost. If a demand defrost is requested and defrost has occurred within the last 90 minutes, the controller initiates a probe test to check for a defective sensor.

During a Probe test, the VGA display shows [PROBE TEST PLEASE WAIT]. The controller operates the unit on high speed evaporator fans only for five minutes. All sensor temperatures are then compared.

• Sensors with large temperature differences are discarded from the control algorithm. The controller then activates the appropriate Alarm codes to identify the defective sensor(s).

Sensor errors recorded during a probe test are cleared when the next Defrost is initiated or Unit On/Off switch is turned Off.

Evaporator Coil (Defrost) Sensor Location Open
		A	Coil Support Bracket
		B	Front of Unit
		C	Insert sensor at least 75 mm into coil between tube rows 2 and 3.

Sensors are permanently calibrated and can be checked using an ohmmeter. Ohm readings should agree with the data shown in the following sensor resistance tables.