InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
Automatic vent dampers:
Here we explain Automatic flue vent dampers, what they are, how they work, and why they can save money on heating bills. 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.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
Automatic Vent Dampers on Heating Equipment Flues
Heating costs can be reduced by any measure that makes sure that as much as possible of the warmth produced by burning a heating fuel (such as natural gas) is sent into the occupied space rather than lost elsewhere.
[Click to enlarge any image]
An automatic vent damper, such as illustrated in Carson Dunlop Associates' sketch here and in our photograph just below, reduces heat loss in buildings where gas-fired heaters are installed.
When the heater is off the electric motor turns the vent damper to the "closed" position so that heat is not lost from the boiler nor the building by natural convection.
When the heater is about to turn on, before the burner is ignited the automatic vent damper motor opens the vent so that combustion gases can flow freely through the flue vent connector and out of the building's chimney.
Don't confuse an automatic flue vent damper with two other "damper" devices: a heating system automatic duct damper or a duct fire damper.
Exactly what is an automatic flue damper?
An automatic flue damper is a device which closes the heating flue when the furnace or boiler is "off" so that we won't continue to lose building heat up the chimney - it's a device to reduce heating costs and save on heating oil consumption.
At left we show an automatic flue damper installed on a gas-fired heating boiler in Two Harbors, Minnesota. This is a Weil-McLain automatic vent damper model RGP-KSF / RVGP-KS. For this model the company specifies:
Damper must be in the open position when the burner fires
Fire clearance: 6-inches from combustibles
Complies with ANSI Z21.66 1994, electrically-operated flue vent damper devicve designed for gas fired heating applian ces
When the heating system has turned off at the end of an "on" cycle of burning fuel, the automatic flue damper electric (see sketch above and photo at left) motor turns a baffle inside of the flue vent connector pipe to a position "across" the pipe so that the airflow inside the pipe is blocked or stopped.
We define and describe in more detail the differences between automatic flue dampers, barometric dampers, fire dampers, and draft inducer fans at TYPES & MODELS of DRAFT REGULATORS
The articles at this website describe the basic components of a home heating system,
how to find the rated heating capacity of an heating system by examining various data tags and components, how to recognize common heating system operating or safety defects, and how to save money on home heating costs.
We include product safety recall and other heating system hazards.
Continue reading at BACKDRAFTING HEATING EQUIPMENT or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
it is impossible to adjust burner for peak efficiency without a properly working regulator.
(Sept 10, 2011) lionel scott said:
In my years of servicing oil fired appliances the most neglected part of the heating system is the draft regulator and as your article points out it is impossible to adjust burner for peak efficiency without a properly working regulator.
Thanks, Lionel, we agree.
Question: s-120-EDP from 120,000 btu Brand sentry Gas fired boiler vent damper vs draft hood
(Nov 28, 2014) Luis said:
i did buy a gas boiler s-120-EDP from 120,000 btu Brand sentry ,it take combustion air from the button of the boiler, it came with a electric vent damper, and do not came with the draft hood . Do i need to put a draft hood on the flue system?
Are there installation instructions with this heater?
Check the manufacturer's specs.
But to be more specific: an electric vent damper is a completely separate device that closes off a vent to stop heat loss up the flue when the heater is not running. It does not address the draft hood requirement for the system.
Your model is a Sentry Natural Gas Water Boiler 120,000 BTU Input, 88,000 BTU Output Intermittent Ignition. Model # S-120-EDP. Most likely the draft hood is built into the boiler and is an integral part of its exhaust system. That's what you'll see in the product illustrations of the "S" boilers. But the SX boilers and some other models definitely show a separate draft hood installed.
Domestic and Commercial Oil Burners, Charles H. Burkhardt, McGraw Hill Book Company, New York 3rd Ed 1969.
National Fuel Gas Code (Z223.1) $16.00 and National Fuel Gas Code Handbook (Z223.2) $47.00 American Gas Association (A.G.A.), 1515 Wilson Boulevard, Arlington, VA 22209 also available from National Fire Protection Association, Batterymarch Park, Quincy, MA 02269. Fundamentals of Gas Appliance Venting and Ventilation, 1985, American Gas Association Laboratories, Engineering Services Department. American Gas Association, 1515 Wilson Boulevard, Arlington, VA 22209. Catalog #XHO585. Reprinted 1989.
The Steam Book, 1984, Training and Education Department, Fluid Handling Division, ITT [probably out of print, possibly available from several home inspection supply companies] Fuel Oil and Oil Heat Magazine, October 1990, offers an update,
Principles of Steam Heating, $13.25 includes postage. Fuel oil & Oil Heat Magazine, 389 Passaic Ave., Fairfield, NJ 07004.
The Lost Art of Steam Heating, Dan Holohan, 516-579-3046 FAX
Principles of Steam Heating, Dan Holohan, technical editor of Fuel Oil and Oil Heat magazine, 389 Passaic Ave., Fairfield, NJ 07004 ($12.+1.25 postage/handling).
"Residential Hydronic (circulating hot water) Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
"Warm Air Heating Systems". Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
Heating, Ventilating, and Air Conditioning Volume I, Heating Fundamentals,
Boilers, Boiler Conversions, James E. Brumbaugh, ISBN 0-672-23389-4 (v. 1) Volume II, Oil, Gas, and Coal Burners, Controls, Ducts, Piping, Valves, James E. Brumbaugh, ISBN 0-672-23390-7 (v. 2) Volume III, Radiant Heating, Water Heaters, Ventilation, Air Conditioning, Heat Pumps, Air Cleaners, James E. Brumbaugh, ISBN 0-672-23383-5 (v. 3) or ISBN 0-672-23380-0 (set) Special Sales Director, Macmillan Publishing Co., 866 Third Ave., New York, NY 10022. Macmillan Publishing Co., NY
Installation Guide for Residential Hydronic Heating Systems
Installation Guide #200, The Hydronics Institute, 35 Russo Place, Berkeley Heights, NJ 07922
The ABC's of Retention Head Oil Burners, National Association of Oil Heat Service Managers, TM 115, National Old Timers' Association of the Energy Industry, PO Box 168, Mineola, NY 11501. (Excellent tips on spotting problems on oil-fired heating equipment. Booklet.)
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: firstname.lastname@example.org. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones