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 Mobile ViewAIR CONDITIONING SYSTEMS HEATING SYSTEMS ANTI SCALD VALVES BACKFLOW PREVENTERS BAROMETRIC DAMPERS BLUERAY Recall BOILERS, HEATING BOILER LEAKS CORROSION STAINS BOILER NOISE SMOKE ODORS BOILER OPERATING PROBLEMS BOILER OPERATION DETAILS BOILER PARTS LIST CARBON MONOXIDE/DIOXIDE CARBON MONOXIDE WARNING CHIMNEY INSPECTION DIAGNOSIS REPAIR CHIMNEYS & Flues - Asbestos Transite Pipe COOL OFF HEAT Thermostat Switch DRAFT REGULATORS - barometric dampers DUCT SYSTEMS DUCT SYSTEM DEFECTS DUCT INSULATION - Asbestos Paper DUCTS - Asbestos Transite Pipe DUST FROM HVAC? ELECTRIC HEAT ELECTRICAL POWER SWITCH FOR HEAT FLUE VENT CONNECTORS FREEZE-PROOF A BUILDING FURNACES, HEATING FURNACE CONTROLS & SWITCHES CAD CELL RELAYS DRAFT HOODS DRAFT REGULATORS FAN AUTO ON CONTROLS FAN LIMIT SWITCH What is a Fan & Limit Switch? Sensing Furnace Temperatures How to Set the Fan & Limit Control How to Test the Fan & Limit Control How to Install the Fan & Limit Control How to Wire the Fan & Limit Control SPILL SWITCHES STACK RELAYS THERMOSTATS ZONE DAMPER CONTROLS FURNACE OPERATION DETAILS GAS PIPING, VALVES, CONTROLS HEAT EXCHANGER LEAKS HEAT LOSS INDICATORS HEATING COST SAVINGS METHODS HEATING LOSS DIAGNOSIS-BOILERS HEATING LOSS DIAGNOSIS-FURNACES HEATING OIL CLOUD WAX GEL POINT HEATING OIL SLUDGE HEATING SYSTEM INSPECTION GUIDE HIGH EFFICIENCY BOILERS/FURNACES INSULATION MOTOR OVERLOAD RESET SWITCH NO HEAT - BOILER / FURNACE DIAGNOSIS ODORS FROM HEATING SYSTEMS OIL BURNERS OIL BURNER NOISE SMOKE ODORS OIL FUEL TYPES & CHARACTERISTICS Oil Odors: Leaky Oil Tank Piping OIL TANKS Oil Tank Leaks and Smells OIL TANK PIPING DEFECTS OIL TANK SLUDGE OIL TANKS, BURIED PLASTIC HEATER VENT PULSE COMBUSTION HEATERS RADIANT HEAT Floor Mistakes to Avoid SAFETY DURING HEATING INSPECTION Safety Recalls BLUERAY Recall CHIMNEYS & Flues - Asbestos Transite Goodman HTPV RECALL Heat Recovery Ventilator RECALL Lennox WARNING Weil McLain RECALL SPILL SWITCHES STACK RELAY SWITCHES STEAM HEATING SYSTEMS TANKLESS COILS THERMAL TRACKING THERMOSTATS Transite Pipe Chimneys & Flues WINTERIZE A BUILDING More Information InspectAPedia ® Home & Site Map Air Conditioning InspectAPedia Bookstore Electrical Environment Exteriors Heating Home Inspection Insulate Ventilate Interiors Mold Inspect/Test Plumbing Water Septic Roofing Structure Accuracy & Bias Pledge Contact Us |
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Because it can be tough for a new owner of an older home to even imagine, much less find where these duct air flow balancing controls are located, we include more photographs of what a manual duct air flow damper control lever might look like. A manual zone damper or heating duct damper or cooling duct damper is particularly valuable in balancing air flow in buildings whose HVAC system includes long duct runs to some areas and short duct runs to other areas. If we take no steps to balance the air flow among building areas, when the blower fan is running, the rooms closest to the blower will receive the most air flow and more distant rooms can be difficult to heat or cool. |
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In general, the handle of the duct airflow control lever or damper is parallel to the damper itself, so if the zone airflow control handle is across the duct it is closing off air flow. If the duct damper handle is parallel to the direction of the ductwork the damper is (probably) open. But if airflow control doesn't seem to work as predicted, some further checking is in order, since it's possible to mount the duct damper handle improperly. The photo at left shows the duct damper handle turned parallel to the direction in which this old (asbestos-paper covered) heating duct runs, so this airflow damper is in the "open" position. |
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As we show here, an alternative to manual heating or cooling air zone dampers is the use of mechanical louvers that can be opened or closed at individual supply air registers. But when an air duct serves multiple rooms in a building, and when we wish that entire area to receive more or less air flow compared with other building areas, it is simpler and more reliable to use a duct damper or zone damper to control the each heated or cooled area at once.
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Photos of automatic zone damper controls wanted - Contact Us
Automatic heating or air conditioning zone dampers are mechanical doors that open or shut under thermostatic control to provide individual area or heating or cooling zone control in buildings served by a single warm air heater or central air conditioner. In response to individual room thermostats the damper opens to permit conditioned air to flow into that room or building area when needed.
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The duct damper is located in an air duct and blocks the flow of warm or cool air into building rooms. It has nothing to do with venting flue gases up a chimney. Our photo shows a motorized zone damper or air duct zone control produced by TrolATemp® a producer of automatic heating system controls. This unit is an automatic opposed-blade duct damper. |
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Here is a commercial automatic air supply register control which contains a booster fan as well. You can spot an automatic zone damper on duct work by noticing that there is an external motor mounted on the ducts in one or more locations. When heating or cooling are not needed in that building area or zone, the duct damper remains in the closed position. Our photo shows a commercial duct damper in a New York City office building. In this case the damper is controlling airflow out of a supply duct into a single ceiling supply plenum and register. |
A fire damper is required in air conditioning and heating ducts in some commercial installations and possibly by local residential building codes in some jurisdictions.
A fire damper might work similarly to an automatic duct damper, but its purpose is quite different: in the event that a fire is detected in a building or in its mechanical systems, (by heat or smoke or other means of fire sensing), the fire damper closes off the air duct to avoid spreading smoke or fire rapidly through the building. The fire damper is otherwise normally "open".
A fire damper and the air ducts where it is installed would typically be located to stop fire spread between floors or other sections of a building, and it would be constructed of fire resistant materials. Think of an automatic fire damper as something like a "fire door" in a building. It closes to prevent fire spread.
Photos of automatic fire dampers & controls wanted - Contact Us
Automatic flue dampers, thermostatically controlled zone dampers, and fire dampers are compared and distinguished at DRAFT REGULATORS.
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10/01/2008 - 09/05/06 http://www.inspect-ny.com/heat/ZoneDampers.htm © Copyright Dan Friedman 2008-1999 All Rights Reserved
