Rumford Technical Discussion

Buckley Rumford Fireplaces
A Guide to Curing Smoking Fireplaces
by Bob Harper

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Today's homes are being built more weather tight and energy conscious than ever before. In response to current trends, architects are designing fireplaces that may suit the homeowner's wishes but may in fact make it susceptible to venting failure or smoking. We now have scientific data that explains the relationship between a fireplace and house. All fireplaces are to a degree susceptible to smoking . This guide was prepared to assist homeowners with mitigating the forces that cause fireplaces to smoke.
The location, type and design of the fireplace are part of the house and therefore a component of a system. They all must work together. As you will see, there are many factors about your house and how you use it that affect the fireplace and vice versa. Keep in mind a few key concepts: 1) Proper user education can overcome most smoking fireplaces.2) A hot flue is a happy flue.3) Externally situated chimneys are colder and therefore more prone to smoking. 4) Most homes don't have enough fresh outdoor air infiltration to balance the warm air rising in the home (The Stack Effect). 5) Aside from all else, the proper installation and use of glass doors is the cheapest and single most effective measure to take against smoking.

List of Do's:
do open the damper fully and leave it so until the next day.
do use only hardwoods cut shorter and seasoned for 12-8 months
do keep ashes to a minimum so air can circulate under the grate and shape them into a ramp.
do keep the fire pushed towards the rear of the firebox.
do start with lots of balled up paper and kindling laid "tipi" fashion to build a bed of coals.
do open the combustion air damper if so supplied.
do open a door or window on the windward side on the first floor before lighting.
do prime the flue with a paper torch prior to lighting the main fire. May have to repeat.
do install and use glass doors per manufacturer.
do keep the fire burning hot.
do open all heating registers and doors to all rooms including the basement.
do turn off all competing fans, vents, or sources of crossdrafts.
do have a Certified Chimney Sweep clean and inspect your system annually.
List of Don'ts:
don't use manufactured wax logs alone. They don't produce enough heat for good draft.
don't use firewood recently purchased unless it has been tested to < 20% moisture content.
don't use any type of lumber, plywood, softwoods, rotten wood, or treated lumber.
don't use any type of chemicals unless you have written permission from your dealer.
don't install or use grates, glass doors, or other accessories unless approved by your dealer.
don't try to burn on very windy days.
don't use large un-split logs with the bark on.
don't add larger logs to the fire until a hot bed of coals is established.
don't "bank" the fire for the night . Stir the remaining fuel up in a hot fire til it is consumed.
don't operate exhaust fans including dryer vents, bathroom vents, kitchen exhausts, heat recovery ventilators, central vacuums, or the main furnace.

If you still experience problems with smoking we recommend you have a blower door test done to identify problems with warm air exfiltration and determine the amount of fresh air intake needed to balance the home. While a professional blower door test is the recognized standard for house pressure diagnostics, a simple test can be performed by your fireplace dealer to get a rough idea of the profile of your home.
Other options at your dealers disposal include extending the chimney height, installing powered and passive air supply ventilators, and installing a powered ventilation fan connected to the two major exhaust fans in the home, usually the clothes dryer and kitchen exhaust vent. When they are turned on the fresh air vent is activated to keep the house balanced.
Understand that depressurized houses are susceptible to backdrafting exhaust fumes from water heaters, boilers, kitchen stoves, clothes dryers, fireplaces, and furnaces. This is all the more reason to test the house pressure profile. Because backdrafting can be a source of carbon monoxide poisoning (CO) we strongly recommend that every home be equipped with a CO alarm as well as smoke alarms.
If a house is experiencing smoking,"roll out", or backdrafting, stop using that offending appliance until it is corrected. You could be exposed to CO and soot up your house. This guide is not intended to be all inclusive. There are others factors that may need to be addressed with any particular house as each house has its own characteristics and users. We make no warranty of the measures herein nor of the omission of others. If you are experiencing problems, contact your dealer for support.
Bob Harper
Pre-Fab Fireplaces, Inc.
Havertown,PA
610 853 4850 (fax 610 853 4857)
rmharper@gateway.net
20Sept. 1999