Carrier 17/19EX - Manual (Page 262)

Troubleshooting Transducers
When troubleshooting transducers, keep the negative lead of your voltohmmeter on terminal
U4 of the power supply (or terminal 4 on power supplies without the comparator circuit).
voltage VO1 = (VH1-VL1) + .467 ± .1 V
For all PIC transducers:
Measured pressure = (507.97 × (
V
out /
V
in)) -47.33
V
out = transducer output ref. to neg. terminal (4 or U4) i.e., VH1 to U4 or VL1 to U4
V
in = power supply output, i.e., U3 to U4
Transducer Replacement
Since the transducers are mounted on Schrader-type fittings, there is no need to remove
refrigerant from the vessel. Disconnect the transducer wiring by pulling up on the locking tab
while pulling up on the weather-tight connecting plug from the end of the transducer. Do not pull
on the transducer wires . Unscrew the transducer from the Schrader fitting. When installing a
new transducer, do not use pipe sealer, which can plug the sensor. Put the plug connector back
on the sensor and snap into place. Check for refrigerant leaks.
Make sure to use a backup wrench on the Schrader fitting whenever removing a
transducer.
WARNING
!
WARNING