🌡 WH8040 1%~99% RH HM-40 Type Digital Air Humidity Control Controller 110V Review

Although it is not obvious from the pictures, you need to connect the power source yourself. Another review has a detailed diagram of how to do this. Once the device is connected, the settings are pretty easy to set up and the product works like a charm.

The relay that is supposed to control the on/off function of the humidifier connected to this unit has failed. During troubleshooting, the relay stayed closed whenever the humidity exceeded the maximum value. Even though my old-fashioned humidity sensor read 95% humidity, the reading began to drop until it was about 7% lower than the other sensor, and continued to drop as this device's reading neared that level HS. And it could be the result of a faulty sensor. So two hits and you're out of…

This little device seems to work very well. It's smaller than I imagined. It does exactly what it says on the tin and can be set to allow you to set a specific relative humidity level as well as the range it can fall (or rise) to before the relay kicks in. This will prevent the relay from tripping every few seconds. It also has a delay feature that does the same thing I suspect, but I haven't tried it. It seems accurate, maybe 3 or 4% below my cheap digital hygrometer, but it can be calibrated…

This controller works as described. Upper and lower limits for humidity and temperature can be easily set. However, the wiring diagrams included in the product documentation do not show the correct "line and load” connection for all applications. With my average electrical knowledge, I was able to figure out the 110 volt AC appliance model controller I bought. I also checked my solution with an electronics expert before making the connections. The humidity sensor lamp has three color coded…

I am always amazed at what modern global manufacturing can do and this is one example. I made a lot of electronic circuits out of circuits as a kid (thanks Forrest Mims III!) and now I find I don't need to do that anymore because even Revain has circuits ready made for very little money. . Considering that this unit probably has some sort of microprocessor in it, is well made, has good screw terminals, does its job perfectly and is easily calibrated, I'm very impressed with its price…

I use this humidistat in the fresh air system in my wine cellar. It is wired in series with two thermal switches that measure the inside and outside temperature to turn on the fans that bring in cold air from the outside. This works great in my San Francisco Bay Area climate, which has cool summer nights. Of course, you don't want to bring in air that is too humid, otherwise you'll get mold, so I limit the humidity in the basement with this controller. This controller works in either humidifier

I never cease to be amazed at what modern global manufacturing is capable of and this is one example. I made a lot of electronic circuits from schematics as a kid (thanks Forrest Mims III!), and now I find I don't have to because even Revain has ready-made circuits for very little money. . Considering there is probably some sort of microprocessor in this unit, it is well made, has good screw terminals, does its job perfectly and is easily calibrated, I am very impressed with its price…

My Rating: This humidistat works well for me. I track them with the La Crosse monitoring system, which saves humidity readings to the remote readout app every 15 minutes, so I know the humidity is being kept at a good level even when I'm away. The reading appears to be within +-3% of the actual value and since the reading can be adjusted to +-5% this is ideal. Changing the settings is also very easy, just press and hold the "Set” button for 3-4 seconds and you will enter the settings menu. From