# MV Short Weatherline PL4800



## jtmis31 (6 mo ago)

I am very much a DIYer and have some experience troubleshooting electrical wiring

I am getting an MV Short error on my Weatherline PL4800.

Here is the background. The unit controls 28 zones. Of the 28 zones, there are three common wires. 1st common wire is wired to zones 1-11, 2nd common is wired to zone 12-22 and the 3rd common is wired to zone 23-28.

Troubleshooting steps: All steps below are done at the control panel. Getting errors when running manual zone programs.

disconnected all three grounds at control panel - no error (short isn't at the control panel, maybe)
connected only common #1 at control panel - MV Short
connected only common #2 at control panel - no error, zones working properly
connected only common #3 at control panel - no error, zones working properly

so the issue is common #1. 
disconnected all live wire at control panel and connected one zone wire at a time at control panel - all MV short error
disconnected all live wire at control panel and connected ONLY common - MV Short

I am not sure how I am getting a short when none of the live wires are connected. There isn't a complete circuit. 
Also, I don't think I have a main valve as I would get a MV short when zones 12-28 are ran. Unless each common wire has its own main valve, so I would have 3 main valves?

Any ideas?


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