Hongso Fireplace Stove Blower Fan Variable Rheostat Speed On/Off Switch Ctrl with 2 Male Connectors, Fireplace Fan Speed Control

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.

Purchased this product to replace a 20 yr old thermostat that had started to fail on my gas fireplace. Magnetic mount made it simple to attach to underside of firebox instead of the screw-mounted thermostat it replaced. Turns the fan on once the fireplace warms up, and turns off after the fire place has cooled down. only question now is how long it will last.

Works well! Used in a gas fireplace with fan.

With this product I was able to lower the fan speed, and reduce overall noise - It has a wider voltage range than the manufacturer OEM. Happy with product!

I ordered this thermostat control for my fireplace blower as the old one quit. Just wanted to be able to have the blower shut down if the fire went out. Has been working flawlessly for 2 years.

I only gave it 4 stars because the seller has not rated the electrical specs for this switch. It may only be a low voltage switch or it may be made for line voltage. There is a difference. Also, DC ratings are different that AC ratings. Everything else, I like. The price is good and delivery was prompt.I do wish people who don't know the facts wouldn't supply answers. The guy who said the voltage didn't make any difference gave inaccurate and possible dangerous information. I hope the vendor decides to include the electrical specs for this unit in the future.UPDATE: I own one of these devices. I am using it with a heat reclamation device on my exhaust vent of my gas heater. These are sold by various vendors, including this one, and none of them have listed the most important details about this switch! The electrical specifications or ratings.I disassembled mine, and printed on the thermostatic switch itself is the following: 125 VAC 10ASo, it is rated for line voltage (in the US & Japan, not Europe) and will also draw up to 10 amps, resistive load.However, most people will use it with a fan or blower, which is an inductive load. Anything up to 600 watts should be safe and that's probably 10 times more than most fans would ever use. A good product!!!FYI: If you notice an appreciable LAG time before turning on, the magnetic bracket acts as a heat-sink and adds a lot of hysteresis (Lag). I drilled out the rivets and mounted mine (without bracket and magnet) right up against the vent pipe and now it works a lot better. I used nylon cable ties (melting point 428-509 degrees F) and ran it around the vent and thru the space between electrical tabs. Works fine, never gets close to melting. You could use metal, but be very careful that you don't short out the electrical contacts.

The magnet attachment is a clever idea, and the heat from my woodstove did not destroy the magnet. The magnet became unglued, but that was an easy fix with furnace cement. The switch became slow to turn on, so I would power the fan from a direct source of AC until it was really hot. I used it to automatically cut off the fan after the stove cooled down.

Added a heat exchanger to our Fireplace this year to capture more heat before heading up the chimney. Wanted to automate the Fan and found this gem.Got an outdoor electrical box and wired up a power cord to an outlet through this sensor switch and a rheostat (to control speed).It turns on when the exchanger reaches 120 and off around 90. This way I can close the doors and go to sleep with the fan running, it will turn off when the fire dies out and the exchanger cools off (but not before capturing a lot of heat!).

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!