Vent Position Sensor (Vps); Upper Vps; Lower Vps; Figure 7.22 Compressor Discharge Temperature Sensor - Carrier Transicold 69NT40-561-001 Operation And Service Manual

1) Sensor
2) Silicon Bead
3. Using the syringe supplied with the replacement sensor, squeeze all of the dielectric compound into the sen-
sor well.
4. Place a bead of the silicone sealer supplied with the replacement sensor around the sensor sealing ring.
Insert sensor into the well with the leads parallel to the suction fitting.
5. Reconnect the sensor (see

7.25 Vent Position Sensor (VPS)

The vent position sensor (VPS) determines the position of the fresh air vent in near real-time via the Cd55.
The fresh air vent position sensor alarm (AL50) will occur if the sensor reading is not stable for four minutes or if the
sensor is outside of its valid range (shorted or open). This can occur if the vent is loose or the panel is defective. To
confirm a defective panel, assure that the wing nut is secure and then power cycle the unit. If the alarm immedi-
ately reappears as active, the panel should be replaced.
The alarm should immediately go inactive, check the 4-minute stability requirement. If the alarm reoccurs after the
four minutes and the panel was known to have been stable, then the sensor should be replaced.
7.25.1

Upper VPS

In order to replace the Upper VPS, the panel must be removed and replaced with another upper fresh air panel
equipped with VPS.
Upon installation, a new VPS assembly requires calibration as follows:
1. Rotate the vent to the 0 CMH / CFM position.
2. Cd45 will automatically display. Press the Enter key and hold for five seconds.
3. After the enter key has been pressed the display will read CAL (for calibration).
4. Press the ALT MODE key and hold for five seconds.
5. After the calibration has been completed, Cd45 will display 0 CMH / CFM.
7.25.2

Lower VPS

Calibration of the Lower VPS is only required when the air makeup slide, motor or sensor has been repaired or serviced.
The VPS is calibrated using the keypad:
1. Remove the two nuts that secure the air makeup panel slide to the unit.

Figure 7.22 Compressor Discharge Temperature Sensor

Figure 7.18) and run Pre-trip P5.
1
2
3) Sensor Well
- - - - -
7–35
3
T-340