Fireplace Restrictor Discs (When You Need One)

If you have been looking for a direct vent fireplace or are wondering how to get the most out of the gas fireplace you already bought, a restrictor disc is an important component to make sure your unit operates properly.

Because of their closed fire box, direct vent fireplaces are very efficient and maintain good air quality in whatever room they are housed in. Though, sometimes they don't heat a room as well as they should. This may lead you to question if you bought a faulty model or a bad brand.

Before you consider returning, or purchasing, a direct vent fireplace, you need to read the manufacturer's instructions and find out if that model requires a restrictor disc for maximum efficiency.

A restrictor disc is a small steel plate that attaches to the exhaust vent to restrict heat from escaping through the fireplace flue. Chimneys with long vent runs or without elbows allow strong drafts to suck heated air out of the fire box.

When the heated air escapes, it doesn't allow enough time for thermal heat to transfer into the room through the glass cover on the fireplace. So, you could have a well-made unit, that seems to not put off much heat, only because it is missing a restrictor disc.

direct vent fireplace

It's important to read the manufacturer's instructions to find out if your fireplace actually needs a restrictor disc based on the length and setup of your venting system. If you have a direct vent fireplace that is designed to use one, and it doesn't have one installed, it will underperform.

However, if you have a unit with elbows or short vent runs that can contain the heated air on its own, and you add a restrictor disc, this could cause the fireplace to overheat.

Installation of a restrictor disc typically looks like attaching the piece to the flue collar. Many of them come with spring action tabs that allow you to easily push it into place within the appliance. This quick step will make a huge difference in the heat output of your direct vent fireplace.

restrictor disc

You don't have to worry if the disc was not set up during the original installation. Typically, you can install it after the fact, without opening up the wall or damaging anything inside the chimney.

So, find your instruction manual and check for the manufacturer's directions if your unit isn't operating at its full potential.

If you have any questions about installing a restrictor disc or determining if you need one, please reach out to our NFI certified techs here.