Wood Furnace Maintenance | Furnacecompare®

Wood Furnace Maintenance

The advantages of using wood heat include price, ambiance, and the quality of radiant heat the unit provides. But there are some key concerns to a wood-burning furnace, too. Sourcing, stacking and manually feeding wood blocks into the unit causes some inconvenience, but many homeowners worry most about the fire risk involved.

The truth is a well-maintained wood stove can be every bit as safe as other fuel methods. With a little help, homeowners can learn to deal with common repair and maintenance issues, and learn troubleshooting tips for any problems that arise. Local HVAC professionals can also help with anything that can’t be handled in-house. Properly maintained, a wood furnace can be a reliable method of using a renewable resource for home heating and comfort.

Common wood furnace problems

The first step in fixing any issues you’re having with wood heat is, of course, to diagnose the problem. After that, you can decide if you can deal with the problem yourself or if you need to get a pro to help you out.

Smoke coming back into the home

The most common issue wood furnace owners experience is smoke coming back down the chimney instead of out the top. Many causes for this can be solved through some general outdoor wood furnace troubleshooting. 

A potential cause is that the chimney temperature is close to the temperature outside. If it’s just not very cold outside or your chimney is exposed to the elements, you could have trouble establishing a good draft. Try pre-heating your flue by holding a heat source next to the flue opening.

Homes that are extremely air-tight can also cause problems for indoor wood-burning furnaces. As warm air from the fire draws up and out the chimney, cooler air needs to come in to replace it. If it can’t, the hot air (and smoke accompanying it) can’t rush out the top. This can make for a sluggish fire and smoke coming out of the furnace doors. If you suspect this is your issue, you can crack a window in your home for a short-term solution to provide fresh air for the fire (and the house’s inhabitants), but you’ll need to ask a pro for help to establish airflow.

Wood not burning

The next easily-diagnosed problem is wood quality. If the wood you’re using is too wet or not well-seasoned, it will be tougher to burn, and wetter when it does burn. Properly seasoned wood has been stacked to allow airflow and left to dry until it’s at 20-25 percent moisture, usually over the course of several months.

Airflow obstructions

If neither of these is your issue, you need to check the airflow through your chimney. If it’s been a while since your last chimney cleaning (more than a year, for instance) then you could have soot build-up in your chimney, which is restricting airflow up and out of your home.

Birds and other wildlife could also cause air obstruction by building a nest or otherwise inhabiting the chimney during the warmer seasons when the chimney wasn’t in use. A quality chimney cap should be placed at the top of the chimney to keep animals and other obstructions out of the chimney. If they’re already there, you can likely get tips from local animal control on how to get them out.

Air obstructions could be caused by objects that are stuck, even on top of a chimney cap, so regular inspections are necessary to make sure leaves, sticks and other trash aren’t blocking airflow.

If you think you may have an airflow issue, but aren’t sure why, you should contact a local HVAC professional to check out your system. Maintaining your wood furnace is important for the performance of your system and for the safety of your home.

General maintenance tips for wood furnaces

There are a few things you’ll have to do on a regular basis to make sure your wood furnace is running at tip-top shape.

Clean your furnace and chimney

First, you’ll have to clean the system and the chimney regularly. This includes clearing out and properly disposing of ash from inside the firebox. Too much ash will cause problems with your burn and allow less room for the wood itself, and it can build up enough to block vents (causing more airflow troubles). You should clean out the ash every two or three days of full-time heating as part of your outdoor wood furnace maintenance.

Chimney cleaning is necessary to get rid of creosote, the black, tarry substance that builds up inside the chimney. It can ignite and cause chimney fires if it’s not cleaned out regularly. So you’ll need to sweep out the chimney or hire a sweep to get the job done. This should be done at least once a year, but checking on buildup every month or two is a good idea.

The heat exchanger on a wood furnace also needs to be cleaned at the end of each heating season to remove build-up to keep the furnace from premature corrosion.

Look for discoloration or warping

You’ll have to check the integrity of the chimney on a regular basis, which you (or your professional) can do during cleaning. Any discoloration or warping could be your first clue that the materials are not as strong as they once were. If you’re not sure if your discolored or warped system is still safe, call a pro to make sure.

Check your seals and air filter

In order for your furnace to burn effectively, the furnace door needs to form a seal when it’s closed. Check the gasket regularly (when the furnace is cool) to make sure it’s in good condition and the door seals completely. If the seal is off, you may have to remove the gasket and install a new one. Check with your local HVAC dealer if you need assistance.

If you have an air filter in your system, it should be checked regularly and replaced when it’s dirty. Replacing every month or two is a typically a good idea.

Take care of your wood furnace and it will take care of you

With proper maintenance and use, wood heat can be a cost-effective, enjoyable way to heat your home using renewable resources. Of course, as with any furnace system, malfunctions can be dangerous, so if you’re ever in doubt, contact a local HVAC professional to talk through your concerns and schedule an inspection.

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