SYNOPSIS: I have one circuit in my house that has killed three Z-Wave 600 Watt dimmers (two Honeywell, one GE, all made by Jasco) in quick succession and I don’t know why. The Z-wave dimmer is on a two-way circuit that controls a pair of outdoor porch lights.
GORY DETAIL: I installed the first Honeywell (Jasco) Z-Wave Plus Smart Light Dimmer Switch (Model 39351) in August 2018. It worked reliably for about four months. Then, when were away in December, I saw “Not available” for that light in the Samsung Connect (Classic) app.
When I returned home, the blue LED light on the switch was out and the switch would not operate the light manually. I killed the breaker and left it off for a while. After restoring power, the switch didn’t come back on. The air gap switch doesn’t restore the dimmer.
I replaced the bad dimmer with an identical spare Honeywell dimmer. The blue LED came on, the switch was visible in the Connect app, the porch light came on, the switch operated manually as it should. After about two minutes of normal operation, the problem recurred: the outdoor light went out, the blue LED went off, it stopped responding to manual control, and it is not discoverable on the network. It just died quietly without any flash, noise or smoke. There was steady 121.6 VAC at the switch; no voltage spikes or reductions were visible in the house; none of the house lights were flickering. Power seems to have stable and well regulated.
Thinking that maybe I got a bad batch of Honeywell dimmers, I bought and installed a GE dimmer (also made by Jasco and identical to the Honeywell dimmers) at Lowe’s. Upon power-up, the porch light went on and the manual switch worked correctly. I was able to rename it in the Connect (Classic) app and save the name change. Three minutes after powering the switch, I went to the “Things” location in the app and saw it was “Not available" – the dimmer had died quietly just like the second Honeywell switch. The blue LED was out, the porch light was out again and switch was dead. Power was steady and there were no storms that might have caused spikes.
I have about 15 other Z-Wave devices in the house and all are working correctly and none have failed. Seven are wired-in switches and dimmers; four are plug-in switches; two are outdoor plug-in switches; and two are battery operated. I don’t think any of these other devices are on the same circuit as the failing dimmer switch, but I’m not 100% positive about that. Unfortunately, I don’t have my house circuit diagram with me at the moment, so I don’t know what else is on the circuit.
The circuit breaker providing power to the circuit is a tandem, so I suspect some circuit modification or addition has been done in the past (we’ve owned the house for 9 months). The breaker does not blow when the dimmer fails.
The switch is wired correctly to hot, neutral, load, and ground. The switch is in a three-gang junction box and there are three different circuits in the box. I’m quite certain that the correct neutral is wired to the switch, but not 100% positive about that. It could be I’m using a neutral from another circuit (bad practice for safety / backfeed reasons), but I don’t think that is the case. I don’t believe that should affect the dimmer as all neutrals are joined on the ground bus bar in the panel.
When we bought the house, this porch light was controlled by a Lutron dimmer/timer switch which I believe operated correctly there for years using the same neutral.
An electrician who has done work for me before has seen something similar with other electronic devices caused by water ingress into a circuit. I haven’t yet checked the porch lights for water. We DID have a huge problem with Christmas lights tripping off a GFCI this past season due to water ingress during rain storms.
Any idea what is going on here? This is really odd and frustrating behavior and I’m at a complete loss here. Anybody have an idea?
Jasco requested one that I send them one of the failed switches for inspection and that is underway.