12 Maintenance and Troubleshooting 
 
 
 
Figure 4: Correct polarity of battery 
 
Only use Panasonic make Lithium battery type BR2032 or equivalent with a nominal voltage 
7.  Ensure that the battery is held securely in its socket and that the battery terminals make good 
contact with the socket terminals. 
8.  Replace the front bazel and relay cover. 
9.  After replacing the lithium coin battery, you must reconfigure and reset the system date and 
time.  
2.3  Replacing the Unit 
If your product should develop a fault while in service, depending on the nature of the fault, the error 
codes will be generated which can be viewed on the relay HMI. First step is to take actions as 
suggested in the Troubleshooting section of this manual. In the unlikely event that the problem persist 
or lies with the wiring and/or terminals, then you must replace the complete device, rewire and re-
commission the device. 
Once the unit has been reinstalled, it should be re-commissioned.   
 
Caution:    If the repair is not performed by an approved service centre, the warranty will 
be invalidated. 
 
 
Caution: Before carrying out any work on the equipment, you should be familiar with the 
contents of  the Safety Information section of this guide or the Safety Guide 
Pxxx-SG-4LM-3  as well as the ratings on the equipment’s rating label. This 
should ensure that no damage 
is caused by incorrect handling of the 
electronic components. 
 
 
Warning:    Before working at the rear of the unit, isolate all voltage and current supplying 
it. 
 
Note:  P153 does not support automatic current transformer shorting. Therefore, for safety reasons CT 
terminals to be shorted when the terminal block is removed.