Strange Connection Issues

I am having difficulty automating relay switches during adverse weather conditions.

However when I walk up to the switches and use the smartthings app on my phone I can control the switch. My phone seems to be acting like a repeater. If I try and control the swich using the app from anywhere other than next to the switch it doesn’t work.

This only happens during adverse weather conditions and only with the relay switches.
I have 6 CT100 thermostats that work flawlessly.

The Hub is located at the center of a 120’x100’ commercial building, thermostats dispersed throughout. The Relay switches are bunched together on the outside edge of the building (for security lights) near the main circuit breaker.

Anyone have similar experience or ideas on why this is happening?


Are your CT100’s running on batteries only? If so, they may not be Z-Wave repeaters. Are your “relay switches” Z-Wave as well? A mesh network works best when devices are spread somewhat uniformly across the area of coverage.

Need a lot more info on what the switches are.
Phone can not work as a relay.

Brand and model of the relays and the thermostats? And where is the hub physically located relative to the relays?

The phone itself can’t act as a repeater, but there can certainly be other things going on.

The other question I would have is whether in adverse conditions you can do anything else with the SmartThings mobile app? At the physical point where you say the phone can’t control relays, can you, for example, do anything else with any other devices? And can you reach other websites using the phone when you were standing in that same position?

In other words, one of the questions we have to determine is whether the issue is the phone getting signal out to the Internet at different locations. If This is a commercial building with a lot of metal inside, it may just be that going out near the relays is improving the communication of the phone to the Internet, not of the devices to the hub.

The switches are Evolve LFM-20
we use 3 of them.

Evolve LFM-20 relay switches
2Gig CT100 thermostats

Rough layout of building
The building is divided into 4 suites roughly 30’x100’ with drywall between suites - lets call them A, B, C and D
each suite is split in half with cinder block - front for office, back for warehouse/work area

Rough locations for hub/internet/devices
6 thermostats, 1 in front and back of suites A, B, C
Internet router is located in front A suite
SmartThings hub in back suite B approx. 10’ from cinder wall and 10’ off the ground
Relay Switches are in back suite D

During the adverse weather, I can control the thermostats and access the internet from my phone…

While weather can effect radio signals, I think it is more a range issue.


Supported Networks:

  • Z-Wave – Signal (Frequency) 908.42 MHz

    Range: Up to 100 feet line of sight between the Wireless Controller and/or the closest Evolve
    Receiver Module

Remember that even a drywall wall can cut signal by 1/3rd. Concrete by 1/2-2/3rds. So with 2-3 concrete walls between the relays and hub, chances are they are barely holding on during best weather condition. The simple added humidity , water in the air during bad weather is enough to bounce the signal around enough to break the bond.
Moving the hub to a more central location, like suite C might be enough to fix, that would only have 1 wall in between the hub and the relays in D . Get some Z-wave repeaters, in Suites C & D to give the relay something to hop off of.

1 Like

The relays are inside the wall and the thermostats are surface mount, so it’s not surprising if the relays have a harder time getting signal through. Also if the relays are on an exterior wall there may be additional insulation, and all that.

So I certainly wouldn’t be surprised if the relays had a harder time.

During adverse conditions, it’s likely that there’s much more humidity in the air, and humidity itself can disperse signal so again, I’m not surprised if it’s not working as well when the weather changes.

But none of that should be affected by the location of the phone. It’s not impossible that signal is bouncing off the phone just because it’s a metal object and thereby somehow hitting the crack or weak spot in the wall that it doesn’t usually, but “not impossible” would still be “really unlikely.”

All of which is to say I’m not surprised that the relays are having a problem, but I am surprised that moving around with the phone is affecting it in anyway.

If it was me as a field tech The first thing I would do is get A zwave plus pocket socket and plug it in on the interior wall near the relays, run a zwave repair, and see if that makes any difference.

There are some other things I’d probably do to isolate the phone’s impact, but that would just be for my own satisfaction because the phone as a factor would drive me crazy. I don’t think it would be worth your time if you just want to solve the problem. :wink:

The CT100s use the C wire for power and they are spread out, however the
LFM20 relay switches are bunched together. Do you think that might be the


I think I’ll try that zwave plus pocket socket.

Thanks everyone for responding.