Alarm transformer causes site fault light & constant clicking

[Anonymous user]

I have a couple of 350ES UPS units that I retired from using on my computer. They are still good and the batteries are holding a charge. Rather than toss or recycle them, I decided to plug one unit into the den and connect my DirecTV DVR & Television just as a battery backup if we have a short power outage.

All seemed fine for a couple of weeks and then the unit started constant clicking and the site ground fault light is lit solidly. I thought that maybe the UPS unit had gone bad, but plugged a new unit into the same circuit with the same problem.

Now, I did a little troubleshooting and tracked it down to the A/C transformer for my alarm system. It's an Ademco 16.5V 25MA A/C adapter for a hard-wired Ademco alarm system. The transformer is 25 years old and has been working OK. But, when I unplug the transformer from the outlet, all of the outlets on the same circuit are working fine - no more clicking or Site Fault light on the UPS unit.

My question is: could the transformer be going bad and causing a problem? I just find it odd that everything was quiet for several weeks and then this problem arose. This transformer has only 2 prongs, so there is no ground prong. Everything was professionally installed, so I assume that this is OK.

Before I plunk down $65.00 for a new transformer I need to determine if there may be something else wrong on this circuit.

Thanks in advance for any suggestions.

SD

[BillP · Accepted solution]

[here is some information on what causes a site wiring fault|http://nam-en.apc.com/cgi-bin/nam_en.cfg/php/enduser/std_adp.php?p_faqid=183]

the clicking to me is indicating the unit is constantly transferring back and forth to battery because it doesnt like whats going on with the circuit. i personally am not sure HOW the transformer could cause this but maybe someone else here may be able to.