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AIR CONDITIONING & HEAT PUMP SYSTEMS
BACKDRAFTING HEATING EQUIPMENT
BACKUP HEAT for HEAT PUMPS
BANGING HEATING PIPES RADIATORS
BLOWER FAN OPERATION & TESTING
BOOKSTORE - InspectAPedia
BTU USAGE MONITORS
CARBON MONOXIDE - CO
CIRCULATOR PUMPS & RELAYS
DIAGNOSTIC GUIDES A/C / HEAT PUMP
DIAGNOSE & FIX HEATING PROBLEMS-BOILER
DIAGNOSE & FIX HEATING PROBLEMS-FURNACE
DIRECT VENTS / SIDE WALL VENTS
DRAFT REGULATORS, DAMPERS, BOOSTERS
DUCT SYSTEM & DUCT DEFECTS
ELECTRIC MOTOR DIAGNOSTIC GUIDE
FAN, AIR HANDLER BLOWER UNIT
FLOODED HEATING EQUIPMENT REPAIR
FLUE SIZE SPECIFICATIONS
GAS BURNER Flame & Noise Defects
GAS PIPING, VALVES, CONTROLS
GEOTHERMAL HEATING SYSTEMS
HEAT PUMPS, DIAGNOSIS, REPAIR
HEATING COST SAVINGS METHODS
HEATING OIL PIPING TROUBLES
HEATING OIL TANKS
HEATING SYSTEM NOISES
HEATING SYSTEM TYPES
GAS LP & NATURAL GAS SAFETY HAZARDS
MANUALS & PARTS GUIDES - HVAC
MIXING / ANTI-SCALD VALVES
MOTOR OVERLOAD RESET SWITCH
NOISE, HEATING SYSTEMS
ODORS FROM HEATING SYSTEMS
OIL FILTERS on HEATING EQUIPMENT
OIL FILL PIPE LEAKS
OIL SPILL CLEANUP / PREVENTION
PLASTIC Plexvent / Ultravent RECALL
PUFFBACKS, OIL BURNER
RELIEF VALVE LEAKS
Reset Switch - Heater Primary Control
RESET SWITCH - ELECTRIC MOTOR
Reset Switch - Stack Relays
SAFETY, HEATING INSPECTION
SAFETY RECALLS CHIMNEYS VENTS HEATERS
SOLAR HEATING SYSTEM DESIGNS
SOOT on OIL FIRED HEATING EQUIPMENT
STEAM HEATING SYSTEMS
THERMOSTATS, HEATING / COOLING
VIDEO GUIDES: Heating System Videos
WINTERIZE A BUILDING
WOOD, COAL STOVES & FIREPLACES
WOOD STOVE SAFETY
ZONE VALVES, HEATING
This article explains the procedure for opening and inspecting heating flues through the barometric damper or draft regulator, with particular emphasis on problems of soot & debris accumulation. Inspecting inside the boiler flue by the draft regulator opening gives very important information about the operating condition of oil fired heating equipment.
A comprehensive list of draft regulator defects are described in detail at Draft Regulator Inspection Points, Defects & Signs of trouble and elaborated further at Questions & Answers about inspecting and adjusting the barometric damper found in our our separate article DRAFT REGULATORS, DAMPERS, BOOSTERS
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In addition to this detailed damper inspection procedure, readers should be sure to review Barometric Damper Defect List. This article series answers most questions about central heating system troubleshooting, inspection, diagnosis, and repairs. We describe how to inspect, troubleshoot and repair heating and air conditioning systems to inform home owners, buyers, and home inspectors of common heating system defects.
Details about draft control on oil fired heating systems (such as the oil fired heater shown in the photo above), including furnaces or boilers, are discussed at DRAFT REGULATORS, DAMPERS, BOOSTERS on oil fired equipment.
At Measure Draft we also discuss how and where to actually measure the heating equipment draft in the course of checking on (or adjusting) the draft regulator.
The barometric damper or draft regulating device we are discussing here is normally used only on oil-fired heating equipment, not on gas-fired equipment. Details about draft control for gas fired heating systems, including furnaces or boilers, are discussed at Furnace Draft Hood on gas fired equipment.
Barometric dampers are devices used to regulate the draft on oil-fired heating equipment such as furnaces, boilers, or water heaters.
On oil fired equipment the barometric damper, or draft regulator is typically a round Tee inserted in the flue vent connector between the heating appliance and the chimney. The face of the tee contains a round "door" with an adjustable weight.
In our photo you may not be able to open this barometric damper - it is improperly installed (out of level), and has been improperly modified, indicating a draft problem with this heating system or its chimney. The implications of sealed barometric dampers are explained at Draft Regulators for oil fired equipment.
How & Why Should You Open & Inspect the Barometric Damper:
When I, the author (DF) first owned a home with a heating boiler I was so terrified of this rumbling flickering box in my basement that I didn't even walk near it. That was a mistake. And we wasted lots of money on oil before we learned that just a few simple visual checks can tell a lot about how well our heating equipment is running.
So don't worry: it's easy to perform this step - anyone can do it if a barometric damper is actually installed where it should be. Just gently push the hinged door open with a finger, and shine a good flashlight inside to see what you can see.
Warning: of course if your oil fired appliance has been running recently, these parts are HOT and you could get burned. If the damper door itself is hot you can still look inside - just use a screwdriver or wire to push the door open rather than your finger as shown in our photo at left.
A barometric damper installed on a horizontal flue pipe will give a good view of the cleanliness of the flue interior as well as clues about rust and damage in the flue.
A barometric damper installed on a vertical flue pipe may still give a good view of the top of the heating boiler, furnace, or water heater, where you may see accumulated soot or debris, rust stains, or perhaps better news.
Guide to Interpreting Debris Visible in the Chimney Through the Cleanout or Draft Regulator
Debris visible in the flue vent connector (stack pipe) visible through the barometric damper draft control opening. If you see soot, rust flakes, and debris in the flue vent connector this means that the heating system needs to be cleaned and serviced.
If the heating system has "just been serviced" this debris means that service was incomplete.
A flue vent connector ((also called the "stack pipe" or "flue pipe") is the metal pipe that connects the oil fired heating appliance to a chimney in order to safely vent combustion gases outdoors.
A proper service procedure for oil fired heating equipment includes removal of the flue vent connector and thorough cleaning of all debris from these components as well as a visual inspection of the condition of the chimney to which the flue vent connector joins to send combustion products outside.
Our photo shows what was probably several years of accumulated soot, rust flakes, and debris in the flue vent connector of an oil-fired horizontal furnace in a wet moldy crawlspace. The owner thought that his system, which was almost impossible to access, had "just been cleaned".
Opening this damper and looking inside meant we literally "hit pay dirt". The dirt meant that the system needed to be cleaned, that the owner was paying for heat, but the heat was going up the chimney, not into the home -- as we explain a bit more below.
A hard to access heating system in a cramped nasty area rarely receives thorough cleaning and service. That was the case for this system.
Question: What is the significance of those "rusty flakes" in the photo of crud visible at the chimney base or through the barometric damper
When I cleaned our flue exhaust, I found 'chips' in the soot like the ones in the image. What are those? I thought they might be from the flue lining chipping off. Are they? - Jessica
The "chips" such as those in our photo are typically soot-coated rust if the flue is metal, or soot-coated flakes of the glazing that was protecting the interior of a clay tile lined chimney flue.
The implications of the chips are that the hard glazed coating is being lost and thus the flue is deteriorating. Just how deteriorated the flue is we can't say from a photo like this one, but it is an indication that a more expert chimney inspection is in order. Use a professional chimney sweep and ask for a complete inspection of the chimney flue interior.
Loss of the chimney tile surface exposes the chimney flue liner to an ever increasing rate of deterioration, especially in climates of harsh or freezing weather. When the chimney liner deteriorates that means that eventually it can become unsafe, risking flue gas leaks, carbon monoxide poisoning, or even sparks and a building fire.
See CHIMNEY CLEANOUT DOORS for more examples of things you may find at the bottom of a chimney when inspecting through the cleanout door, or if it's a "dead end flue" you may find these inspecting through the flue vent connector or, if the flue is without bends and elbows, you may be able to inspect right through the barometric damper such as in our photo above.
When & Why is soot or crud in the oil fired boiler or furnace flue a problem?
When we look in to the flue close to the heating boiler or furnace, such as at the barometric damper shown at the top of this page, it's normal to see a thin coating of soot on the interior of the metal flue pipe (photo at left and photo at page top). .
But thick soot in the flue, the chimney, or inside of the boiler or furnace heat exchanger is a problem (photo below).
Our photo of a soot problem indicator (left) shows soot accumulating in the oil burner flue of the heating boiler connected to the "too short" chimney discussed at Chimney Height & Clearance.
This boiler has a history of blowing soot out of the boiler room and through the garage of the home it serves. This same soot is, of course, accumulating inside the heating boiler itself.
Because soot acts like an insulating coating, too much soot in a heating system causes both system operating problems problems and increased heating cost for the building.
These soot problems on oil fired heating equipment are discussed in detail at SOOT on OIL FIRED HEATING EQUIPMENT.
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Frequently Asked Questions (FAQs) about draft regulator & barometric damper inspection & troubleshooting
Questions & answers or comments about the importance of accumulated soot & debris in the heating flue vent connector viewed through the draft regulator opening or by other means. .
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