Good/Cheap ZWave Plus Relay?

I need to buy two relays, one is to control a 110V outdoor light (the relay will be in a weatherproof box) and one will be to just be a dry contact on a condensate pump. For the condensate pump I saw people recommending is a nice cheap dry contact relay.

What about for my outdoor light? I had been buying but is there anything cheaper than $40 out there I could use?

There is this one...

Hmm seems like a possibility. Seems weird that their dual relay is much cheaper than the single??

It is a little odd, perhaps this is a temporary promotional price or a pricing error. Could always jump on it (in case it is an error) before it goes up lol.


Did you ever get that wired up to your condensate pump wire terminals and is it working well?
I just had another flood and have been looking at smart alert options...

Yup. It’s working great. You just have to make sure your rules or whatever account for the fact that the relay will open when the pump runs. So I set mine to only alert if it stays open >30s


Pardon me if I’m trying to figure this out as it does my head in a little:

So it’s a window/door sensor with screw terminals on both halves which you wire to the two leads from the condensate pump correct? And you keep these sensors right next to each other the entire time?

So if the overflow/float from the pump rises too much, it would normally break the circuit (one would ordinarily splice the red wire coming from the thermostat to an air handler to shut down equipment in the case of an emergency.) In this case, it would tell the contact sensor that there was a break the signal from the pump?

I was under the impression that the relay only opens/breaks as a fail-safe if the float in the pumps go higher than they are meant to either due to an obstruction, motor issue, or relay issue. I may be wrong, but I don’t think it should break every time it runs on a regular basis as if it was wired to an air handler (a typical application), opening the pump relay would cause a thermostat/air handler to shut down every time. Perhaps this happens to you only because you don’t form a fully closed/complete circuit with those sensors?

And one last thing: is your pump providing continuous power to the contact sensor through the screw terminals or do you still need batteries?

I was thinking of adding additional splices to continue on to the red thermostat to air handler to shut down my equipment still and this would only function as an additional alert.

No. The magnet is just a magnet, there are no terminals on that. You don't need it. Both of the terminals are on the "main side"

I can't speak to how yours works, I can only say that's not how mine works. Whenever the float rises to the point where the pump runs, the relay closes.

I don't know what this means. The relay is an NO relay, meaning the circuit is normally open and closes when the relay is tripped. If there wasn't a closed circuit, It wouldn't work.

No, the device is a battery powered device. It is a dry relay, power does not flow across the relay circuit. The relay circuit is just to detect when the float rises.

I can't speak to this, I do not have this hooked up to an air handler so there is no other equipment to hook up to it.


Thanks for taking the time for a detailed reply. It’s much appreciated.

Usually, the leads for condensation pumps let the current flow freely from a thermostat through the pump and into an air handler. When the float rises to much, the relay in the pump severs the circuit.

I assumed somehow that your sensor’s magnet somehow had a terminal in that too and that’s why I was confused as to how the setup actually worked. Turns out you don’t need it at all.

However now I’m trying to brainstorm why your sensor triggers every time during ordinary pump operation as it probably should only do this when the relay hits a higher level (obstruction or failure.)

Right now I have mine spliced into to the R wire of my thermostat and it only triggers shutoff if I overextend the float too high. It’s a Little Giant condensation pump btw.

Hmm interesting, I have a Little Giant pump as well, this one in fact

I have a slightly cheaper white model from them. One theory I have is that your pump might be hitting the high float limit every time it runs. It could happen if it’s imbalanced. Maybe I’m totally wrong it might be worth checking into.

That's possible, it's mounted on/hanging from a wall so it's possible it's not entirely level. That said, it doesn't cause me any problems (had it for years). It's hooked up to a heat pump water heater so there is nothing to turn off if there is an issue, it's more just to notify me so I can go and replace the pump.

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I had two floods in my basement from the same Mars pump. I thought it was an issue with the PVC line at first because it was working after I had checked and cleaned everything. It ruined a bunch of drywall panels that I was going to use to finish my basement. The second flood happened this past weekend luckily (or unluckily) before I was about to hang up the new drywall.

I discovered that the installers for my HVAC (Mars) and tankless water heater (Little Giant) never bothered to hook up the safety switch on both of them which would’ve prevented these floods altogether. Now that my basement is almost finished, I’m not taking any chances. It would also be nice to have an alert like you have set up instead of just cutting the thermostat or hot water tank.

I have water sensors that communicate with my Dome Water Shutoff Valve but as luck would have it I didn’t have them in those locations which working on finishing the space.

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