Re: Water Heater Thermometer
Reply #2 –
Since we're talking about thermostats, I want to mention a unit that I recently bought that does an outstanding job at a very low price. Two products, actually. One's a thermostat and one's a thermometer.
First, the thermostat. Fair warning: to make this work with your water heater, you'd have to do some wiring. I haven't tried, although I might someday when I have nothing better to do. Same goes for your fridge, although that is the application I bought it for. But with my Vitrifrigo fridge, it was easy to disconnect the two wires from its mechanical thermostat and substitute two wires from this electronic one. Dometics? I dunno.
With that said, the Inkbird (yeah, I know, goofy name) is a general-purpose electronic thermostat that can control heating or cooling devices, or both, and it's both cheap ($15) and very accurate. It's a compact little box that's easy to wire in and program. It has two relays--one for heating and one for cooling--that can handle up to ten amps each. You can set both the temperature and the amount of variation allowed (hysteresis, for you engineers) in one-degree increments. It comes with a small waterproof temperature probe.
They apparently sell a lot of these to people who are brewing beer, hatching chicken eggs, or things like that. I could see using it to control a yogurt maker, a fridge, or anywhere you need precise control. In my case, I found that the temperature in my fridge was fluctuating more than I'd like, so I wired in an Inkbird instead of the built-in thermostat. I set it for 38° F and a 2° variation. The attached graph shows the result over a week of time. As you can see, it stayed very close to 39° (it can be calibrated, but I havenât bothered), the only exception being when I loaded a bunch of groceries and it briefly spiked up to 43.7°. I donât have a comparable graph from the fridgeâs original thermostat, but believe me, the fluctuation was MUCH greater!
Two things that the Inkbird instructions donât make clear: 1) It needs 12 V power to run, and terminal 1 must be positive. 2) It doesnât supply power to your heating and cooling devices; itâs just a switch (well, two switches). Keep that in mind, and wiring it up will be straighforward.
So how did I get that neat temperature graph? I used a
Govee wireless thermometer. This is another $15 item, and this one you might actually find handy. Iâve tried many different wireless thermometers in the past twenty years, and none of them worked very well or kept on working for very long. This one does. It talks to your phone or tablet via Bluetooth, and the free Govee app does a great job of summarizing and graphing the temperature and humidity (it measures both).
I have four of these now, used to monitor and record the temperatures in my fridges (Airstream, Trillium, and car) and in my small climate-controlled storage room. They work flawlessly. If you have a need to monitor temperature and/or humidity, especially over time, this little gadget will do it.
One caveat: that Govee model is not weatherproof, so it shouldn't be used outdoors. I believe they make a model that is weatherproof, but I don't have that information handy.
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