What's the most difficult problem you've ever had to troubleshoot and fix?

What’s the most difficult problem you’ve ever had to troubleshoot and fix?

For me, considering none of my wires are labeled and there are too many color codes, just putting wires out of screw terminals can be difficult. I don’t have supervised NACs and I once had an open circuit somewhere and I had to find it. I didn’t know which conductor was open. I had to check + and - behind each device and under each raceway until I found it, all without a multimeter (I misplaced it). The best part is - there was no open circuit - the NAC power supply was unplugged. Wasted a whole 45 minutes on that, but at least I tidied up my wiring.

Currently, I have everything figured out as long as I don’t take wires out of screw terminals. I have yet to label my wiring in my panel (I should, considering I have 16.8vac, 12vdc, and 24vdc going in and out)

The most confusing issue I’ve run into was when, during filming of a System Test video, the zone for the Waterflow switch on my demonstration board refused to register an alarm.

The way it is configured, the waterflow switch is connected to a Radionics D9127U POPIT Module on an older Radionics D8125 POPIT Loop. The D8125 is connected to a DMP 736P Interface Module, which reports the POPIT statuses to the LX-Bus on my DMP XR500. After all is said and done, the Waterflow reports an alarm condition to Zone 505. This zone is configured with a short retard delay, after which it will trip a “Fire” zone type alarm condition on the XR500. 505 is mapped to the #6 Open Collector Output, which activates the #4 relay on a Model 860 Relay Board. The #4 relay is wired into Zone 4 on my Siemens SXL-EX, which will, at long last, activate a fire alarm condition on the panel.

As you can see, there is a crap load of places where something could go wrong. In all seriousness though, in reality this set-up is a lot simpler than it sounds typed out in detail.

I eventually narrowed down the problem to the POPIT loop itself. The issue ended up being the presence of an “extra” POPIT Module on the loop, which was not registered with the programming. The extra POPIT, a Radionics D8126T on Zone Address 502, was installed to monitor the trouble contacts in my Ansul AutoPulse 2000. However, since I do not have stand-by batteries for it, that panel is in a state of perpetual trouble. For the time being, I decided to remove the Zone from the programming to avoid a constant Supervisory alarm on the DMP system. This worked for about a year, however I believe that the presence of this module eventually caused the system to become “confused” in a way that prevented the chain of modules from properly reporting the alarm condition. I added 502 back into the programming as an Aux 2 zone type, and set the zone to Alarm on an Open condition. Since the AutoPulse trouble contacts are always closed, this effectively prevents the Supervisory from appearing until I can obtain stand-by batteries. After adding the Zone Address for the “extra” module back to the programming, the POPIT loop has performed flawlessly ever since.

Not every time but, Map Faults… Any EST guru here will feel my pain…