OK, winging it, I removed the unit and took it to the shop. I opened it up and started testing components (after removing the dead roaches and grease, all tested good. I plugged her in she worked great, wish I would have tryed power on 1st at shop instead of diving in. Never could get it to malfunction trying different setting and various times a day for 3 days (Weekend). Reassembled unit and test again, good. Loaded unit in van and haul it back to customers home and reinstalled it. Turned it on zap E21. The only way to reset the unit is to unplug it, so I unplugged it and pluged it into the other recepticle on the duplex,it worked fine.
I examined the recepticle to find it was ungrounded and the unit plug was not making good contact on the neutral side of the plug. Haven't heard any complaints from the old gal for a week so, maybe I found the problem.