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Fireplace Dampers – Throat Dampers vs Top-Mount Dampers

Fireplace dampers are an important component of your fireplace system and are often overlooked. Dampers serve the critical purpose of closing off the chimney when the fireplace is not in use. It’s an energy efficiency device, saving you money by preventing the loss of heat during the winter and preventing the loss of air conditioning during the summer. An open or a missing damper is like having an open window all the time.

What is a Fireplace Damper?

In simple terms, a damper is a metal plate that closes the chimney flue. Homeowners often get the terms “damper” and “flue” mixed up. They’re very different but they work together. The damper is a metal plate; the flue is the pipe.

What is a Throat Damper?

Dampers come in different types and styles. Most dampers that are part of original construction are called “throat dampers” because they’re located in the throat of the fireplace, above the firebox (where you make the fire) and below the smoke chamber and flue pipe. These throat dampers come in various styles–pivot hatchets, poker, rotary, spiral, vestal, Allied/Donley, and Majestic.

Different regions of the country have different kinds of dampers. Another interesting point is that many dampers on the East Coast are removable and replaceable. This makes it much easier for chimney sweeps to be able to do a thorough cleaning of the system, especially into the smoke shelf behind the damper, because they don’t have to fight around the damper plate.

Here in San Diego and most of the West Coast, dampers are not removable and replaceable. That means that once the damper is damaged beyond repair, the damper cannot be replaced in the throat of the chimney without tearing open the facade which would be cost-prohibitive. In that case, there’s another solution–a top-mount damper.

What is a Top-Mount Damper?

If a throat damper becomes damaged beyond repair and cannot be replaced, our industry has created a solution called a Top-Mount Damper, also known as a Top-Sealing Damper.

This damper is placed at the top of the chimney stack. Most of these types of dampers are operated by a cable that runs all the way down the flue pipe and into a bracket inside the firebox. To close the damper, you simply pull the chain down and lock it in the bracket. To open the damper, you unhook the cable from the bracket and it pops open at the top because it’s spring-activated.

Top-mount dampers come in different styles. Some of the top-mount dampers are referred to as “Ice breakers,” to be used in colder regions.

Four advantages to Top-Mount Dampers:

* Top-Mount Dampers seal better which will save you money on utility bills. When the cable is pulled down, the damper plate seals against a rubber, silicone or rope gasket which gives it a tight seal. Throat dampers, on the other hand, never provide a complete seal, especially as they get older and the damper plate warps. Without the seal, there are gaps that allow heat loss during the winter. Top-mount dampers will increase energy efficiency in your home and save you money in heating during the winter and air conditioning during the summer.

* For cold climate areas, the top-mount dampers keep the warm air inside the flue, helping the draft and reducing the likelihood of smoke coming into the room.

* If you don’t have a chimney cap, rodents and birds can come down the chimney and enter the house. The top-mount damper closes the chimney at the top, making it impossible for critters to get in.

* Here in San Diego and other parts of Southern California, we have a serious problem with aggressive Africanized Bees. Bees like to build their hives in chimneys. With a typical throat damper, the bees have free access to build their hive in the flue. A chimney cap isn’t enough to prevent the bees from entering the flue. With a top-mount damper, the flue is completely closed off at the top, making it almost impossible for bees to enter the flue.

One caveat…

Top-mount dampers can only be installed on masonry chimneys with open fireplaces. They cannot be installed in prefab fireplaces, free-standing stoves or Rampart General Pre-Cast systems due to the U.L. listing. The top-mount dampers also cannot be installed with windcaps.

In addition, top-mount dampers cannot be installed for a fireplace that has artificial gas logs or a log lighter because the damper must be locked fully open.

If you need your existing throat damper repaired or you’re in the market for a top-mount damper, contact a CSIA Certified Chimney Sweep.

Gas key inside gas valve for fireplace serving artificial gas logs

How Do I Turn On Artificial Gas Logs?

Artificial gas logs on fire with glowing emberss below the grate. Enjoying a beautiful fire from your artificial gas logs is one of life’s simple pleasures. Not only do gas logs provide warmth but they also provide instant ambiance, coziness and even romance. Another benefit is that you can enjoy your artificial gas logs for just ten minutes in the morning as you savor a cup of coffee before starting off your day or a glass of wine in the evening when you return home from work.

Here in San Diego, the majority of homeowners who have artificial gas logs use a lighter and a key to start the fire. It’s referred to as “Match Lit.” Unfortunately many people are intimidated by the process of starting their gas logs. If you do it wrong, it can be a terrifying experience and even dangerous. But it doesn’t have to be a frightening process to start an artificial gas log fire, if you know a few simple tips.

There’s a right way and a wrong way to light the gas for gas logs to avoid a mini gas explosion in your fireplace.

Five Steps To Turning On Gas Logs The Right Way

Step 1: The fireplace gas valve will usually be located on either the right side or left side of the fireplace. In some rare cases, the valve may be in front of the fireplace in the hearth extension or in the floor in front of the fireplace. This valve, by code, must be readily accessible and visible. The valve cannot be hidden inside a cabinet. It should be within six feet of the fireplace opening. The gas valve should never be located inside the firebox! 

Examples of gas keys to turn on artificial gas logs in a fireplace
Examples of gas keys

In one hand, hold a long-stem lighter or a long match. In the other hand, place the gas key into the hole of the gas valve. You may have to wiggle the gas key around until you feel it “grab.”

Step 2: With your other hand, place the lit match or lighter near the gas tray/burner pan located underneath the grate.

Step 3: At the same time, very slightly turn the gas valve counter-clockwise.

Step 4: The gas will slowly enter into the burner tray and the flames will appear in the gas tray/burner pan under the artificial gas logs.

Step 5: Then, and only then, turn the gas valve counter-clockwise to whatever level you want the flames.

This is the same process used if you have a log lighter for starting a wood fire or for lighting your outdoor propane BBQ grill.

The Wrong Way To Start Your Artificial Gas Logs

Following the previous steps above is a full-proof way to safely start your gas logs. However, here’s an example of what happens if you do it the wrong way.

The WRONG WAY: You turn the gas valve all the way on. Then you take your time, going around the house, looking for a lighter or match. You finally find one. In the meantime, the fireplace is full of gas. You light the match or lighter under the grate and then POOF! You may experience a little mini explosion in your face with perhaps even some singed hair or eye brows.

My point is…slightly turn on the gas valve only AFTER placing the lit match or lit lighter to the burner tray.

A Few More Important Tips with Artificial Gas Logs

If you have children, don’t leave the key perched inside the valve. Kids Gas key inside gas valve for fireplace serving artificial gas logslove to play with the key. If your child turns the key, the gas will be turned on which would be extremely dangerous. In addition, for whatever reason, children love to poke small toys and crayons into the hole for the gas valve which may ruin the gas valve. We advise homeowners to cover the hole for the gas valve to prevent children from accessing the valve.

If you have glass doors in front of your fireplace, those glass doors must be fully open when the artificial gas logs are on. Closing the glass doors during an active fire creates a vacuum which may cause the glass in the glass doors to implode or explode. Here’s a video of Kelly Rippa, celebrity morning talk show host, who experienced this frightening event.  When you’re not using the fireplace, close the glass doors so you don’t have the heat loss from your home.

When a fireplace is plumbed for gas, the damper must be locked in a fully-open position.  This is like having an open window all the time and you will lose heat from your home during the winter. Glass doors will prevent the heat loss from the home.

Never have the artificial gas logs on at the same time as your central heater/furnace. Depending on how tight your house is, or how close the air intake is from your furnace to the fireplace may make your fireplace lose its draw so instead of the gases going up the pipe, those dangerous gases may be drawn into the room where you’re sitting in the living area.

In Conclusion….

Following these five very simple steps will give you an ABSOLUTELY FOOL-PROOF method to enjoy your artificial gas logs.


Photo credits: Rick Pocock