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Thermal Fireplace Blowers (What You Need To Know)

Thermal Fireplace Blowers (What You Need To Know)

Thermally activated blowers are a super helpful accessory for any fireplace or stove. A fireplace blower speeds up the process of heating your home, though it can not extend the area the heat is able to cover. The use of this tool will move stagnant air from the appliance to other chilled places in the room so the heat is evenly distributed.

A thermal blower consists of four main parts. There is a rotary fan/motor, rheostat on and off switch, thermal switch and wiring harness. While each part may bring a different level of confusion for untrained eyes, many people lose faith in the effectiveness of a thermal blower because of a misunderstanding of how the rotary fan works.

The rotary fan has several angled strips of metal, called louvers, that spin inside a circular drum when powered up. Once moving, they move air up and out of the fireplace or stove they are installed into. Seems simple enough right?

Well, the problem comes when the fan doesn't immediately spin when the rheostat switch is flipped on. This leads people to believe the motor is defective or the fan has stopped working altogether. So, it is important to understand that the thermal switch is the key component of the fan that determines when the fan will turn on.

Thermal Fireplace Blowers (What You Need To Know)
thermal switch

The thermal switch contains a bimetallic strip that has to be heated to around 120 degrees before it closes and allows voltage to flow to the fan motor and begin operating. That barrier is there so the fan doesn't rush into action as soon as it is turned on and blow cold air around the room.

While pushing cold air into an already chilly room is bad enough if the fan didn't wait until properly heated to begin operating it could also cause poor heating inside the unit. For gas models, this would look like awkward flame patterns. With wood-burning models, they may never get to burn as efficiently as they should because too much heat is pulled away from the unit.

Thermal Fireplace Blowers (What You Need To Know)
thermal blower

So, if you have a thermal blower that doesn't turn on immediately, don't worry! It is doing its job. We recommend that you leave the rheostat power switch on at all times. When the thermal switch is warm enough it will power the rest of the unit on its own. If you don't want to use the blower at any point you can always turn it off and easily shut down operation.

Well, that is it for the quick Tech Tuesday article. We hope you learned a little and feel more at ease operating a thermal blower. If you have any questions, contact our NFI techs anytime between 8:30a - 5:30p CT.

About the Author

Collin Champagne

With over 13 years in the industry, Collin is a National Fireplace Institute (NFI) certified technician and managed content for the eFireplacestore and eCanopy brands. He has achieved the highest NFI certification possible as a Master Hearth Professional and is certified in all three hearth appliance fields: wood, gas, and pellet. With experience with sales and in-field installations, his expertise shines through his technical knowledge and way with words.

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