Guide to Heating Radiators, Baseboards & Convectors
Diagnose & Repair Cold Radiators or Baseboards
RADIATORS - CONTENTS: How to identify, inspect, diagnose, and repair problems with hot water or steam radiators, baseboards, or heating convectors - if your radiator or baseboard is cold and the heating system is "on" - here we diagnose the problem. Where leaks occur on hot water and steam radiators, convectors, and baseboards. We discuss: cold radiator problems, how baseboard heat works, how convector heaters work, how to assess unusually sized or shaped baseboards, heating convectors, or radiators.
POST a QUESTION or READ FAQs about troubleshooting heating system radiators, baseboards, convectors - hot water heating systems and steam heating systems
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Cold radiator diagnosis & repair home page: this article series describes the types of all types of heating radiators: hot water, steam, cast iron, heat convectors, baseboard heat, electric heating convectors, and we explain the diagnosis and repair of no-heat or leaks or other problems with heating radiators.
How to Identify and Diagnose Problems With Hot Water or Steam Radiators, Baseboards, or Convector Units
In addition to cast iron radiators using hot water or steam as a heat source, we describe two other very common hot water heat distribution methods below. Our photo above (at page top) shows a typical "one pipe system" steam cast-iron heating radiator. A single pipe delivers steam to the radiator and condensate from the cooling steam returns to the heating boiler via that same pipe.
[Click to enlarge any image]
This article series answers most questions about all types of heating systems and gives important inspection, safety, and repair advice.
Below we describe the identification and function of different types of heating output devices in hot water or steam heated buildings. First, here is a quick no-heat diagnostic guide for radiators & baseboards. Detailed diagnostics are in the articles we cite.
Radiators or baseboards do not get hot? - Quick Troubleshooting
Is the heat on? Make sure that your room thermostat is set to a temperature higher than the temperature in the room - so that it is calling for heat.
Is the heater working? Make sure that your heating boiler is working, that is that the heating boiler turns on and off normally. A hot water heating boiler may not turn on immediately when you turn up the room thermostat: if the water temperature in the boiler is already above the aquastat's cut-in temperature the circulators will send hot water to the radiator and the boiler will turn on later when its temperature is dropped by returning water from the cooler radiators in the building.
Don't forget to check for having run out of heating fuel. If your heating system is not working properly, see NO HEAT - BOILER.
Hot water heating baseboard is warmed by hot water circulating through either finned copper tubing or through cast iron baseboard sections. Carson Dunlop's sketch (below left) and our photo of a heating baseboard (below-right) show a typical modern hot water heating baseboard system installation.
Heating baseboard warms the room by a combination of radiation (the hot baseboard radiates heat onto surfaces in the room) and convection (cool air enters at the baseboard bottom, is warmed, and exits at the baseboard top - see Carson Dunlop's baseboard sketch above left). Electric heating baseboard also warms by radiation and convection but the baseboard itself is heated by an electric element rather than hot water.
Hot water baseboard details: details about inspecting, installing, diagnosing, or repairing baseboard heat are
at BASEBOARD HEAT.
Electric baseboard heat details: details about electric baseboard heat are
at ELECTRIC HEAT.
What is a Heating Convector or Wall Convector? & How Do Heating Convectors Work?
Sketch of a wall convector (above left) courtesy of Carson Dunlop and our photo (above right) show a traditional wall-mounted heating convector unit.
Our photo was taken in a 1920's home in New York. A heating convector unit operates much like a radiator (page top photo) but instead of thick cast iron used to radiate heat, the convector is made of copper tubing covered with metal fins, or of cast iron with cast-in fins.
Our photo (left) shows a leaky heating convector that was recessed into the wall. While recessed heating convectors were popular for aesthetic reasons (no radiator projects into the room), often a high percentage of the heat is flowing through the exterior wall to outside.
The heat source in a wall-convector may be forced hot water, gravity hot water, steam, or the unit may be heated by electricity.
Electric-heated wall convectors and some other convector units may incorporate a blower fan to increase the heat output from the device. Our photographs of a wall-mounted heating convector (above) show a wall unit that is heated by steam.
Conventional wall-mounted heating convectors (units that do not include a fan or blower) rely on natural movement of warm-air upwards to draw cooler air in from the floor level. You'll notice that there is a very generous air intake space along the bottom of the convector - it is designed to move plenty of air across its heating coil.
As the convector gets hot, cool air is drawn up from floor level, is heated by the fins on the convector, and warm air is supplied out of the convector's front grille.
Details about wall convectors used for heating or cooling and about convector blower fans are found
at WALL CONVECTORS HVAC
Electrically-heated, steam heated, or hot water heated fan convector heating units similar to what you see in our photo here but boosted by a fan that blows room air across the heater are discussed
at FAN CONVECTOR HEATERS - HYDRONIC COILS.
Once every year or so, we like to take the covers off of heating convectors to inspect the unit for leaks.
While we're at it, we make certain that the heat exchanging fins on the heating convector are not dust-clogged (photo at left). If your building is occupied by pets who shed much hair this step can be very important.
Getting good air flow through the heat exchanging fins of all finned heat exchanging devices such as heating convectors or finned copper tubing heating baseboards can make a significant difference in liberating the heat output from the device.
Just gently vacuum off the convector using a brush attachment and your vacuum cleaner - take care not to bend the fins. A heating service contractor can provide more aggressive cleaning using special products, but on residential heating equipment that has not been exposed to some unusual problem we usually don't find it necessary.
What are These Unfamiliar, Weird-Shaped or Oddly-Located Heating Radiators?
If you are wondering why a cast iron radiator is found mounted high on a building wall or even on a ceiling, the explanation may be found in the sketch (above left) from Carson Dunlop Associates.
For buildings in which hot water circulated through the heating distribution system by gravity - that is, without using the forced hot water provided by a circulator pump - the only way we could get hot water to rise into a heating radiator was to be certain that the radiator was physically located higher than the top of the heating boiler.
If you find a shelf-like cast iron radiator like the one shown in our photo (above right) where it is being admired by a red-jacketed realtor the radiator will probably located in the kitchen or pantry of an older home where it performed double duty as a plate warmer. The cast iron radiator in our photo, with its three flat shelves, was serving dual-duty as a both a heat source and as a plate warmer for plates coming out of a chilly pantry or dish closet.
Hello, I'm having trouble leaving a comment so that is why I am emailing you.
I recently purchased a house built in 1960. It is a brick ranch. I have recessed radiators. I've never seen radiators like this. They are literally in the wall and do not look like your standard radiator. While trying to clean behind them, I noticed some type of foil which is stapled to some sort of insulating board that looks like card board on the bottom. Could this brown fiberboard contain asbestos? I've been worried sick over this. Any help or comment is appreciated. - A.S. 8/4/2014
The foil faced board behind the recessed radiator was added to help direct heat out into the room and is in a position where even if the board contained asbestos (which I doubt based on the ones I've seen) it is in a position where mechanical disturbance is very unlikely - making the risk very low.
If you want to send us some sharp photos of the whole radiator in-wall installation and closeups of the reflective board you have seen I will be glad to comment further.
A recessed heating convector (newer than your radiator most likely) is shown in the article above. And comments about improving the heat output of recessed radiators are at RADIATOR BASEBOARD or CONVECTOR COVERS
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Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. Mr. Cramer serves on the ASHI Home Inspection Standards. Contact Mark Cramer at: 727-595-4211 mark@BestTampaInspector.com
John Cranor is an ASHI member and a home inspector (The House Whisperer) is located in Glen Allen, VA 23060. He is also a contributor to InspectApedia.com in several technical areas such as plumbing and appliances (dryer vents). Contact Mr. Cranor at 804-747-7747 or by Email: firstname.lastname@example.org
Home Inspection Education Home Study Courses - ASHI@Home Training 10-course program. 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 Home Reference Book, a reference & inspection report product for building owners & inspectors. 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.
The Home Reference eBook, an electronic version for PCs, the iPad, iPhone, & Android smart phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter inspectaehrb in the order payment page "Promo/Redemption" space.
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.
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.
Eric Galow, Galow Homes, Lagrangeville, NY. Mr. Galow can be reached by email: email@example.com or by telephone: 914-474-6613. Mr. Galow specializes in residential construction including both new homes and repairs, renovations, and additions.
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, (see next item in this list). ITT Fluid Technology,
1133 Westchester Avenue
White Plains, NY 10604,
tel +1 914 304 1700 fax +1 914 696 2950 www.ittfluidbusiness.com
Principles of Steam Heating, $13.25 includes postage. Fuel oil & Oil Heat Magazine, 389 Passaic Ave., Fairfield, NJ 07004.
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.)
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
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.
Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.
Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates' Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment
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.
Links to our list of additional information on heating system inspection, repair, maintenance