Electric Tankless Water Heater Interfering with Zwave?

Community Playground Getting Started & Initial Setup
1

Hi Everyone:

I just finished installing Veralite and some devices today. Everything went fairly smoothly until I decided to take a shower.

After installing the following:

12 - GE 45612 Dimmers
3 - GE 45614 3 Way Kits
2 - Jasco 1P Switches 45609WB

I went and turned on the water to take a shower. Almost instantly every Zwave based light started to flicker from 100% to 50% and back. I left the water going took voltage readings and saw a stable 121V at the devices. I still have standard switches and dimmers in the house with the same LED bulbs / retro kits and they were not doing this. This house was built to handle the Tankless load on it, and I’ve never had light dims when it turned on. The only thing I can come up with in my head is the three variable elements in the heater are creating harmonics due to their non linear loads and this is interfering with the Zwave devices.

Anyone else have any ideas? It seems to keep the Zwave I may need to ditch the tankless.

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I’m going to be a bit, perhaps excessively, literal for the sake of clarity.

Z-Wave is a communication protocol that utilizes the 908MHz(In U.S.) spectrum. It is not impervious to interference. Interference can cause decreased radio frequency range or even completely inhibit Z-Wave communication. It is very rare(I’ve yet to hear of any real case) and highly unlikely that interference will cause unintended or spurious Z-Wave operation such as changing a dimmer setting. The description of your issue does not sound related to Z-Wave.

It sounds as though you are experiencing flickering AC LED bulbs attached to GE/Jasco dimmers when the water heater is on, probably due to noise on the AC line disturbing the triac dimmer’s pulses. Since you state that the same type LED bulbs do not flicker on “standard” dimmers we can assume that the issue may not not(entirely) be the LED bulbs.

The GE/Jasco dimmers are triac type dimmers. What type of dimmers are your “standard” dimmers, triac or rheostat?

If your standard dimmers are also triac dimmers, the issue might be the GE/Jasco dimmers and you might resolve the issue with a different dimmer like the Evolve LRM-AS Dimmer which are triac type dimmers.

If however, your “standard” dimmers are rheostat type dimmers, the issue may well be related to the bulbs in combination with triac dimmers and simply replacing the GE dimmer with another brand will not resolve the issue. In this case another bulb may solve the issue or a dummy load may be required.

Testing the dummy load theory is very easy if there are multiple bulbs on a single switch. Simply replace one of the bulbs with an incandescent bulb and see if the flickering persists.

3

Thanks for the post Z-Waver, it actually explained a lot to me.

My “Standard” Dimmers are Leviton 6633-P. There discontinued. I did find this cutsheet.

http://assets.twacomm.com/assets/pdf/17800.pdf

That’s a triac I think? Also they cutsheet says “Built-in radio/TV interference filter”. Unsure if that’s what preventing them from doing the same thing?

I also tried what you said about sticking a 60W Incandecent Bulb into one of the circuits. Circuit has 1 - Cree 9.5W retrokit in it and a 65BR30 Incandecent. I turned the hot water on, flicker is gone. How would I go about dummy loading? I found it via search on the fourms.