Resistance C heck
Turn off the control po wer and disconnect the terminal plug of the sensor in question f rom the
module. Measure sensor resista nce between re ceptacles desig nated by the wiring diagram with
a digital ohmmeter. The resistance and corre sponding tempera tu re is listed in Table 9 A or
Table 9B. Check the r es is t ance of both wires to gro und. This resista nc e s ho uld be infinite.
Voltage Drop
Using a digital voltmete r, the voltage drop ac r os s any en ergized sensor can be measured
while the control is ene r giz e d. Table 9A or Table 9B lis t s the relationship be tween temperature
and sensor voltag e drop (volts d c measured acro ss the energi zed sensor). E xercise care wh en
measuring voltage to pre vent damage to the sens o r leads, connector pl ugs, and modules.
Sensor wire should also be checked at the sensor plu g connection. Chec k th e sensor wire by
removing the condens er at the sensor and me asure for 5 vdc back to th e module if the contro l is
powered.
CAUTION CAUTION
!
Relieve all refriger an t pressure or drain the w ater prior to replac in g the tempera-
ture sensors.