Variable Rheostat

As an electrician, I was skeptical how well this item would perform but for the price, I gave it a shot. I have to confess that it is still confusing to me how it actually functions but it does. I use it to control a blower on the back of my wood stove that is controlled by a variable speed switch. This item perfectly turns the blower on when the stove is heated to approx. 120 deg. and shuts it down at 90 Deg. I placed it on the back upper corner of the stove and have not had to move it at all to maximize its performance. I also connected it to a 3 point on/off/on toggle switch from Amazon in a box so I can either control it manually or on auto just in case. Still don't completely understand how it works but I highly recommend it!

Worked perfectly. Been three years. Happy with my buy.

Not being an electrician I can't speak to the technicalities on this switch. it doesn't operate like the old rheostat switch did but it still works. (Rheostat meaning variable speeds or voltage applied...like a dimmer switch) it seems to have a much lower end to it where much of the travel of the knob creates very little actual fan speed. That could be relays, circuit boards, warp speed... But it is not an OEM equipment and I don't know if all the electronics are matching or agreeing with purchased switch, but enough matches, the size the fit the 110 AC two wire type splice into the stove controls. Turn it all the way up and I get full fan speed, turn a third down and it's barely turning. So I've got two thirds more knob and nowhere to go with the fan speed. That'll be fine for me. Some of the lower reviews sound like they're using this switch for unintended applications. It's a woodburning stove variable fan switch, designed to control the air blowing off your stove into the room, thus heating your room. Applying this switch to computer fans, and bathroom exhaust fans can only give you extreme unintended consequences, that may lead to poor performance or just dangerous. Use it for a wood burning stove. Use a dimmer switch for your exhaust fan (lutron is the best) and go to geek squad to fix the computer or you're going to end up like "the fly" or traveling back in time or sumptin'...

My search for a heat activated switch needed for my project found this. The pros: + Low price of $7.99 with free Amazon shipping! ◄ This is a very good price! + Pretty good customer product reviews. + Sensor rated - 10 A, 125 VAC, 50°C ◄ See my the first attached picture. + Advertised - magnetic mount thermostat switch for fireplace stove blower. + Advertised - strong magnet, easy and simple to place ◄ Very handy, worked perfectly on my project! + Advertised - temperature switch closes (turn on) at approximately 120°F, opens (shut off) at approximately 90°F (+/- 5°F tolerance). + Advertised - measures 2 1/2-inches in length by 1-3/4-inches in width. + Advertised - 2-year limit warranty. The cons: - The wiring terminals are exposed, which can be a shock hazard when used with 120 VAC line voltage. ◄ I covered the the terminal with shrink tubing, but parts of the terminal still remain exposed. - No documentation or wiring is included! You will only receive a thermostat sensor mounted on a magnetic bracket. - The heat has to transfer... pass thru the metal mounting to reach the sensor. ◄ I removed the sensor, applied computer heat sink compound on the sensor button & reattached it to the mounting bracket with screws. This promotes faster operation, as the heat is transferred to the sensor sooner! See my second attached picture. If you opt to do this, consider using flat head screws & countersinking the bracket, so the bracket will mount flush with the heated surface. This wasn't necessary in my application. - No country of origin. ◄ I'm going to say this is made in China, for those that prefer to buy products made in the USA. The problem - what this device helped to resolve: We have 4 attic storage area exhaust fans installed to keep the garage & attic storage area cool during the summer. 4 fans, each rated at 210 CFM, so 4 fans = 840 CFM of air flow! That much exhaust causes outside air to be drawn down the 4" natural gas water heater flue... B-vent pipe chimney, when it's cold... not in use. When the natural gas water heater starts heating, burner on full, the B-vent pipe chimney is cold, so there's no flue gases draw up the B-vent chimney pipe. The natural draw up the B-vent pipe doesn't occur until the B-vent pipe chimney liner is heated by the hot flue gases. When the attic storage area fans are operating, the outside cold air is drawn down the B-vent pipe chimney into the garage. This prevents the hot flue gases from going up the B-vent pipe chimney to heat it up the pipe to create a natural draw. Instead of going up the B-vent pipe chimney, the hot flue gases are pulled into the garage, which is unsafe! The solution: The solution to this problem is simple. Detect the hot flue gases being sucked into the garage & switch off the attic exhaust fans! Theory of operation: The Thermostat sensor is heated by the natural gas water heater hot flue gases being pulled past the sensor. Refer to the third & forth attached pictures to see how the Thermostat sensor is positioned on the natural gas water heater flue hood. Once the sensor reaches around 120°F, it operates, which in turn operates a 12 VDC relay that turns off the attic storage area exhaust fans. A note on the relay: The attic storage area exhaust fans operate thru the relay NC - normally closed contact, so when the relay operates, the attic storage area fans are turned off. When the relay is off, not operated, the attic area exhaust fans are on. Of course that's assuming they were on... operating via the attic temperature sensor switch or manually turned on. Theory of operation, continued: When the thermostat sensor drops to around 90°F, the thermostat sensor turns off. This opens the 12 VDC relay circuit, which switches the attic storage area fans back on. Once the natural gas water heater B-vent chimney pipe is hot, the draw is strong enough to where it will continue, even with the attic area storage exhaust fans are operating. This review focuses on this thermostat sensor switch, so it doesn't show the exhaust fan side, where the 12 VDC relay & power supply are located. If you're interested, I did do customer product reviews on the 12 VDC relay, the project boxes & even the magnets I used on the project box to attach it to the metal water heater. Closing remarks: ▪ Thus far, this thermostat sensor switch has been working perfectly! If it continues to work as it is now, I'll consider upping the product rating.

This thermo switch was delivered in 2 days & got my fireplace fan working again - another spree of 20 degree nights -- Magnet is quite strong and product has plenty of prior positive reviews Thanks !!!

This was easy to install

This fits from an electronic state to run the fans.. It is opposite on the speed control where the QF unit turned the knob on then it was right at high speed, turn the knob further and the fans slow down. This "Hongso" Rheostat is the opposite where it is slow at the start then turns the knob and fast is on the other end of the twist. The electrical male/female connectors are not the correct plastic housing size to fit directly to the QF wood stove. I snipped them off the Hongso rheostat and added the correct ones to fit the QF unit. The quadrafire rheostat does run a small metal U Bracket for to act as a heat shield around the rheostat but is easily modified with a Dremel tool to fit the new one. For the $10 here and the minor adjustment it was worth the "risk vs reward" to skip paying for the more expensive OEM unit. If these modifications seem more work for you, then look for a 3amp 115v rheostat. That is what the quadrafire unit electrically requires as a replacement.

The thermostat replaced a two year old thermostat that was slow to turn on the fan. I am very happy with the new thermostat! From the time I turned on the gas until the fan came on was 8 minutes. The old thermostat took 20 minutes!!

fonctionne bien

I liked it, used on a pellet stove blower fan

This item is not meant for blower motors!! It says "Dimmer switch Tungsten only" stamped on the housing. Amazon policy states: "The return mailing labels obtained from the Amazon.ca Online Returns Centre are valid only for returns shipped within Canada"; therefore I cannot return this item!