I am looking to control an immersion heater using my VeraLite / LightwaveRF system.
Total newbie so this would be one of the first things I do. To switch the immersion heater I considered just using a standard Z-Wave Aeon Labs Micro switch. However that is limited to 10A, and my immersion heater is 20A (i think?).
That should work OK - with a couple of provisions:
The solid-state relay will dissipate some heat when turned on. You would need to consult the device’s data-sheet to find out how much but it is likely to be several Watts. You would probably need to mount it on some metal to stop it overheating. Actual electromagnetic relays (contactors) dissipate much less heat so may be easier to house.
If you do use a solid-state relay, you should feed it with a module that has an actual relay output rather than a solid-state one. I don’t know about the Aeon modules but the Fibaro FGS211 (1x3kW) or FGS221 (2x1.5kW) would be fine for this.
Take a look at the Intermatic CA3750. It’s a high current contactor with built in zwave.
I’d just be a little careful about running such a heater unattended. What are the consequences of it running too long? Could a tank explode? Water come to a boil and burn animals mouths?.. Just put some thought to the negative scenarios so you are thinking through fail safe modes… What happens if vera fires up heater and then locks up on a software glitch?
Maybe use an STC-1000 (or a similar local thermostat probe to the water) to control the heater and just disable power to this self controlled loop via Vera.
If I remember correctly, the CA3750 has three layers of PCBs stacked with offsets and relays in between. As I recall, the Z-Wave chip’s location in the stack makes for a somewhat directional signal. The signal is a little weak in some directions and quite normal in others.
If you are in the UK or Ireland with a fairly modern fuseboard, your best bet is to fit a contactor or relay on the board like this one [url=http://www.ebay.ie/itm/GE-CTX-666131-20a-Normally-Open-Contactor-240v-Coil-Used-/141205027610]GE CTX 666131 20a Normally Open Contactor 240v Coil Used | eBay. You can then drive this with a Fibaro relay or similar. Given the high currents involved, the quality of your connections will be very important, so I would strongly recommend that you get a properly certified electrician to do this for you.
I have 2 CA3750 one for each water heater. The one in the rear detached garage is probley 100 feet away with several walls in between. But I have a large z-wave network in both the garage and the house.
So Altho this one device might have a slight shorter range (I never had a problem) if it’s not your only device or located to far away I don’t see any issue.
Both of those options (the Intermatic CA3750) and the normally open contactor look like good options.
I think I will go for the CA3750 because that way I can do a straight swap over for the existing double pole switch that I have installed there. All I need to do now is find someone in the UK that sells it.
Just want to be clear. They wouldn’t work the same way. The immersion heater would be more dangerous.
Turning on and off a wAter heater leaves the thermostat and safety overlimit controls still in tact downstream from the contactor. This is a key point.
Controlling a 1500w heating element without any thermostat loop or over limit safety control could be dangerous.
Just want to be clear. They wouldn’t work the same way. The immersion heater would be more dangerous.
Turning on and off a wAter heater leaves the thermostat and safety overlimit controls still in tact downstream from the contactor. This is a key point.
Controlling a 1500w heating element without any thermostat loop or over limit safety control could be dangerous.
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It’s the same unless he has no thermostat and is using vera as the old means to turn off, but I highly doubt his heater has no thermostat on it.
The relay only opens and closes the circuit. It doesn’t inject power and bypass the rest of the system. So if you wire it in before the thermostat or after the thermostat power still comes threw the thermostat and dependant on that as a main shut off. This relay gives you and option to turn it off.
I would always want temp control and overheat protect outside of the vera. I am assuming the op’s heater is set up this way. Likely trying to save energy by not having in on all day.
And nice to automate it so you can stop trying to remember to do it😀. I would think the away mode would be good for shutting it off, but you would have to have a inbound to pre-warm. Just wondering if anything will grow in there while it is sitting there cool for months. Might want to flush it when you arrive anyway.